Crazy Cooling System (Overheating)
05-23-2011, 07:36 PM
#1
Supporting Maxima.org Member
Thread Starter
iTrader: (9)
Join Date: Oct 2003
Location: Austin, TX
Posts: 1,232
Crazy Cooling System (Overheating)
I'm hoping that someone will be able to identify with my symptoms or point me in a direction that doesn't involve tearing something down unnecessarily 
Background: Since I've moved to Texas, I've been having issues with my VE/Z running hot (no kidding, right?
). Initially, the car would run fine on the highway, just like my Max did, at around 180 deg. When I was stuck in traffic on warm/hot days, my temp would start to creep up and keep going until I turned the heater on, which I usually did at 210-215. That would bring the temp back down. I was also loosing coolant to where I had to add more every week or so. It turned out my water pump was leaking a bit from the weep hole, which I found after coming home one day and having the overflow tank puke all over the ground.
I also had an intermittant problem where my Autometer gauge would not register temp (it is located in the bypass hose between the WP and Rad. Inlet) in-sync with the dummy dash gauge. I NEVER had this problem in the Maxima.
I replaced the water pump with a new OEM one, and also replaced the radiator with a Koyo factory replacement. I went ahead and did the thermostat using a brand new OEM one, which previously was a new OReilly's brand.
I also replaced my single rigged Maxima radiator fan with one of these:
(3.8L Taurus fan... this bad boy moves some air and fits perfectly between the upper and lower tanks)
So now, having replaced all of that, the VE runs hotter on the highway than it did before, around 190-195. Intially it was alright (aside from running a tad hotter), both gauges were in-sync, and the thermostat seemed to be working properly. Soon after, my Autometer gauge stopped reading temperature when starting cold, and the dash gauge would rise normally, but get up close to the H after a bit. Eventually, the dash gauge temp would drop to normal and the Autometer would start registering temp. I check the coolant level and it was low. I added more, and burped twice, and initially it was working well again for a couple days. Now I'm getting the same thing, where the dash gauge is reading temp, getting up to the H and hanging out for awhile, then eventually coming back to normal while the Autometer reads hardly anything until the dash temp drops. Once the temp gets to normal, I can run it like always and the temps stay 185-210. Checking coolant levels, I'm not really losing anything.
I checked compression, and got the following:
#1 - 150 #2 - 145
#3 - 135 #4 - 150
#5 - 140 #6 - 145
Keep in mind I have low compression pistons. I'm not blowing smoke, and dont see any fluid contamination nor wet plugs. #3 is a bit low, but I hesitate to pin it on a head gasket. I didn't check it with oil to distinguish rings vs. head leaks.
Today, the car does the same thing running close to H without anything on my Autometer. I shut it down and checked the rad. hoses, and both are very firm, with the upper being very hot and lower cold. At this point, I know my T-stat isnt opening properly. I'm getting fairly hot air through my heater. When it is getting close to the H, I can leave the heater on and drive VERY easy to keep the temp from pegging, but it stays up there until the system opens up.
What are your thoughts, does this sound like a bad thermostat (new OEM), air still in the system, bad head gasket, or something else entirely?
Please help if you can, and thanks for reading my life story here!
Background: Since I've moved to Texas, I've been having issues with my VE/Z running hot (no kidding, right?
). Initially, the car would run fine on the highway, just like my Max did, at around 180 deg. When I was stuck in traffic on warm/hot days, my temp would start to creep up and keep going until I turned the heater on, which I usually did at 210-215. That would bring the temp back down. I was also loosing coolant to where I had to add more every week or so. It turned out my water pump was leaking a bit from the weep hole, which I found after coming home one day and having the overflow tank puke all over the ground.I also had an intermittant problem where my Autometer gauge would not register temp (it is located in the bypass hose between the WP and Rad. Inlet) in-sync with the dummy dash gauge. I NEVER had this problem in the Maxima.
I replaced the water pump with a new OEM one, and also replaced the radiator with a Koyo factory replacement. I went ahead and did the thermostat using a brand new OEM one, which previously was a new OReilly's brand.
I also replaced my single rigged Maxima radiator fan with one of these:
(3.8L Taurus fan... this bad boy moves some air and fits perfectly between the upper and lower tanks)
So now, having replaced all of that, the VE runs hotter on the highway than it did before, around 190-195. Intially it was alright (aside from running a tad hotter), both gauges were in-sync, and the thermostat seemed to be working properly. Soon after, my Autometer gauge stopped reading temperature when starting cold, and the dash gauge would rise normally, but get up close to the H after a bit. Eventually, the dash gauge temp would drop to normal and the Autometer would start registering temp. I check the coolant level and it was low. I added more, and burped twice, and initially it was working well again for a couple days. Now I'm getting the same thing, where the dash gauge is reading temp, getting up to the H and hanging out for awhile, then eventually coming back to normal while the Autometer reads hardly anything until the dash temp drops. Once the temp gets to normal, I can run it like always and the temps stay 185-210. Checking coolant levels, I'm not really losing anything.
I checked compression, and got the following:
#1 - 150 #2 - 145
#3 - 135 #4 - 150
#5 - 140 #6 - 145
Keep in mind I have low compression pistons. I'm not blowing smoke, and dont see any fluid contamination nor wet plugs. #3 is a bit low, but I hesitate to pin it on a head gasket. I didn't check it with oil to distinguish rings vs. head leaks.
Today, the car does the same thing running close to H without anything on my Autometer. I shut it down and checked the rad. hoses, and both are very firm, with the upper being very hot and lower cold. At this point, I know my T-stat isnt opening properly. I'm getting fairly hot air through my heater. When it is getting close to the H, I can leave the heater on and drive VERY easy to keep the temp from pegging, but it stays up there until the system opens up.
What are your thoughts, does this sound like a bad thermostat (new OEM), air still in the system, bad head gasket, or something else entirely?
Please help if you can, and thanks for reading my life story here!
Last edited by Brad92SE; 05-23-2011 at 07:40 PM.
05-23-2011, 07:58 PM
#2
I'm going to vote on wonky thermostat and maybe some air in the system.
you still have the old t-stat?
you might cut the guts out of the middle so you have a blanking plate with a 1" ish orifice.
stick that in and see how the car does.
you DO have the little dingle ball thingy at the top of the t-stat, dont' you?
any chance you put it in backwards? I wouldn't think that would cause it to do that, but you never know..
If you get it running, I have a race at TWS this weekend. you should come up so we can catch up and have a few beers!
you still have the old t-stat?
you might cut the guts out of the middle so you have a blanking plate with a 1" ish orifice.
stick that in and see how the car does.
you DO have the little dingle ball thingy at the top of the t-stat, dont' you?
any chance you put it in backwards? I wouldn't think that would cause it to do that, but you never know..
If you get it running, I have a race at TWS this weekend. you should come up so we can catch up and have a few beers!
05-24-2011, 04:36 AM
#3
Supporting Maxima.org Member
Thread Starter
iTrader: (9)
Join Date: Oct 2003
Location: Austin, TX
Posts: 1,232
I'm going to vote on wonky thermostat and maybe some air in the system.
you still have the old t-stat?
you might cut the guts out of the middle so you have a blanking plate with a 1" ish orifice.
stick that in and see how the car does.
you DO have the little dingle ball thingy at the top of the t-stat, dont' you?
any chance you put it in backwards? I wouldn't think that would cause it to do that, but you never know..
If you get it running, I have a race at TWS this weekend. you should come up so we can catch up and have a few beers!
you still have the old t-stat?
you might cut the guts out of the middle so you have a blanking plate with a 1" ish orifice.
stick that in and see how the car does.
you DO have the little dingle ball thingy at the top of the t-stat, dont' you?
any chance you put it in backwards? I wouldn't think that would cause it to do that, but you never know..
If you get it running, I have a race at TWS this weekend. you should come up so we can catch up and have a few beers!
I'm going to try burping again on a huge hill near my apartment one day this week. I hate to replace the stat again because I made it a PITA to get to, but I have to do 4 injectors soon anyways I suppose.
I should be able to make it out this weekend... once the cooling system opens up it runs normal
What day/time?
05-24-2011, 06:37 AM
#4
I'm going to vote on wonky thermostat and maybe some air in the system.
you still have the old t-stat?
you might cut the guts out of the middle so you have a blanking plate with a 1" ish orifice.
stick that in and see how the car does.
you DO have the little dingle ball thingy at the top of the t-stat, dont' you?
any chance you put it in backwards? I wouldn't think that would cause it to do that, but you never know..
If you get it running, I have a race at TWS this weekend. you should come up so we can catch up and have a few beers!
you still have the old t-stat?
you might cut the guts out of the middle so you have a blanking plate with a 1" ish orifice.
stick that in and see how the car does.
you DO have the little dingle ball thingy at the top of the t-stat, dont' you?
any chance you put it in backwards? I wouldn't think that would cause it to do that, but you never know..
If you get it running, I have a race at TWS this weekend. you should come up so we can catch up and have a few beers!
05-24-2011, 07:01 AM
#5
Brad, there's a practice day on Friday I'm hoping to get up to. I've got a new rear diff I'm trying out and need time to swap before the race if I'm slower with it than I was with the factory one. (at MSRH, I was 3 sec a lap slower. at TMS I'm 5 sec faster... just depends on the track!)
There's a race on Sat and sunday, usually they start around. qualifying starts around 8 for all groups, then first race runs before lunch (around 11-11:30.) then they start back up around 12:30-1 and run until about 5.
same schedule on sunday.
I'm currently not sure which group I'm running in- they're moving us around some right now and I wont' know till friday. either group 3 or group 6. group 3 will race about 1:30 or so, group 6 will race about 3.
The RTV shouldn't make any effect on the t-stat unless you got enough on there to close it off. you're smarter than that though.
just get a cheap t-stat from the parts store and cut the guts out and run without one for a short while. see if that helps the problem. it's summer so you really don't need one until october. it'll buy you some time at least..
There's a race on Sat and sunday, usually they start around. qualifying starts around 8 for all groups, then first race runs before lunch (around 11-11:30.) then they start back up around 12:30-1 and run until about 5.
same schedule on sunday.
I'm currently not sure which group I'm running in- they're moving us around some right now and I wont' know till friday. either group 3 or group 6. group 3 will race about 1:30 or so, group 6 will race about 3.
The RTV shouldn't make any effect on the t-stat unless you got enough on there to close it off. you're smarter than that though.
just get a cheap t-stat from the parts store and cut the guts out and run without one for a short while. see if that helps the problem. it's summer so you really don't need one until october. it'll buy you some time at least..
05-24-2011, 07:09 AM
#6
Brad, there's a practice day on Friday I'm hoping to get up to. I've got a new rear diff I'm trying out and need time to swap before the race if I'm slower with it than I was with the factory one. (at MSRH, I was 3 sec a lap slower. at TMS I'm 5 sec faster... just depends on the track!)
There's a race on Sat and sunday, usually they start around. qualifying starts around 8 for all groups, then first race runs before lunch (around 11-11:30.) then they start back up around 12:30-1 and run until about 5.
same schedule on sunday.
I'm currently not sure which group I'm running in- they're moving us around some right now and I wont' know till friday. either group 3 or group 6. group 3 will race about 1:30 or so, group 6 will race about 3.
The RTV shouldn't make any effect on the t-stat unless you got enough on there to close it off. you're smarter than that though.
just get a cheap t-stat from the parts store and cut the guts out and run without one for a short while. see if that helps the problem. it's summer so you really don't need one until october. it'll buy you some time at least..
There's a race on Sat and sunday, usually they start around. qualifying starts around 8 for all groups, then first race runs before lunch (around 11-11:30.) then they start back up around 12:30-1 and run until about 5.
same schedule on sunday.
I'm currently not sure which group I'm running in- they're moving us around some right now and I wont' know till friday. either group 3 or group 6. group 3 will race about 1:30 or so, group 6 will race about 3.
The RTV shouldn't make any effect on the t-stat unless you got enough on there to close it off. you're smarter than that though.
just get a cheap t-stat from the parts store and cut the guts out and run without one for a short while. see if that helps the problem. it's summer so you really don't need one until october. it'll buy you some time at least..
Off topic but you mentioned races and you know that's gonna catch my curiosity. Whatcha racing? I know you guys are big into the race scene over by you. The quarter mile track right by where I live now is closed down and now there's only the open wheel races in Riverhead, L.I.N.Y.. Got pics of what your racing.
05-24-2011, 09:08 AM
#7
Banned
Join Date: Jul 2006
Location: Okc 405
Posts: 999
He's in autocross in a 240sx shiloh51933.
Alright so heres my understanding and thoughts on what could be your problem brad. Gutting a thermostat can also be bad because. without the thermostat controlling the rate of flow you could actual only cause your motor to heat up more if the flow of coolant into the engine is to fast there for not having enough time for heat. ever consider checking your radiator cap to make sure its still good? http://www.nismoparts.com/catalog/?section=312#1144 Nismo 62Degree's Celcius T-stat the very T-stat im running and haven't had a single problem from it in over 4 years with cooling.
Now for why i say gutting a thermostat could be a bad option. Here is a quote from the college automotive technology book to back up my theory as to why cutting the center out could by chance cause more heating to happen then even what is happening now.
Chapter 12 - Lubricating and cooling systems.
Thermostat
The Thermostat controls the minimum operating temperature of the engine. The maximum operating temperature is controlled by the amount of heat being produced by the engine at the time and the cooling system's ability to dissipate the heat.
The technical definition of a thermostat is a temperature responsive control valve. The thermostat controls the temperature and amount of coolant entering the radiator. While the engine is cold, the thermostat remains closed, allowing coolant to circulate only inside the engine. This allows the engine to warm up uniformly and eliminates hot spots. When the coolant reaches the opening temperature of the thermostat, the thermostat begins to allow some flow of the coolant to the radiator. The hotter the coolant gets, the more the thermostat opens, allowing more coolant to flow through the radiator. Once the coolant has passed the radiator and has given up its heat, it re-enters the water pump. here it is again pushed through the passages surrounding the combustion chambers to pick up heat and start the cycle once again.
Today's thermostat is composed of a specially formulated wax and powered metal pellet, which is tightly contained in a heat-conducting copper cup equipped with a piston inside a rubber boot.Heat causes the wax pellet to expand, forcing the piston outward, which opens the valve of the thermostat. Today's thermostats are also designed to slow down coolant flow when they are open. This helps prevent overheating that can result from the coolant moving too quickly through the engine, reducing its effectiveness in absorbing heat.
so there you have it as to why removing and or gutting the T-stat is not a good idea.
Alright so heres my understanding and thoughts on what could be your problem brad. Gutting a thermostat can also be bad because. without the thermostat controlling the rate of flow you could actual only cause your motor to heat up more if the flow of coolant into the engine is to fast there for not having enough time for heat. ever consider checking your radiator cap to make sure its still good? http://www.nismoparts.com/catalog/?section=312#1144 Nismo 62Degree's Celcius T-stat the very T-stat im running and haven't had a single problem from it in over 4 years with cooling.
Now for why i say gutting a thermostat could be a bad option. Here is a quote from the college automotive technology book to back up my theory as to why cutting the center out could by chance cause more heating to happen then even what is happening now.
Chapter 12 - Lubricating and cooling systems.
Thermostat
The Thermostat controls the minimum operating temperature of the engine. The maximum operating temperature is controlled by the amount of heat being produced by the engine at the time and the cooling system's ability to dissipate the heat.
The technical definition of a thermostat is a temperature responsive control valve. The thermostat controls the temperature and amount of coolant entering the radiator. While the engine is cold, the thermostat remains closed, allowing coolant to circulate only inside the engine. This allows the engine to warm up uniformly and eliminates hot spots. When the coolant reaches the opening temperature of the thermostat, the thermostat begins to allow some flow of the coolant to the radiator. The hotter the coolant gets, the more the thermostat opens, allowing more coolant to flow through the radiator. Once the coolant has passed the radiator and has given up its heat, it re-enters the water pump. here it is again pushed through the passages surrounding the combustion chambers to pick up heat and start the cycle once again.
Today's thermostat is composed of a specially formulated wax and powered metal pellet, which is tightly contained in a heat-conducting copper cup equipped with a piston inside a rubber boot.Heat causes the wax pellet to expand, forcing the piston outward, which opens the valve of the thermostat. Today's thermostats are also designed to slow down coolant flow when they are open. This helps prevent overheating that can result from the coolant moving too quickly through the engine, reducing its effectiveness in absorbing heat.
so there you have it as to why removing and or gutting the T-stat is not a good idea.
Last edited by elusivemax93; 05-24-2011 at 09:15 AM.
05-24-2011, 10:02 AM
#8
I have an S14 (240SX) that I road race in SCCA Club Racing. way more fun than autoX.
http://forums.maxima.org/autocrossin...ake-stuff.html
Some video of a race in Jan with a cold, wet track... you can see how slippery it is in the vids. fawk I hate running that track in the rain!
http://www.youtube.com/watch?v=MkT3QbD_r7s
I can't find the vids of some of my other races since I'd borrowed a friend's camera and he did the uploads. don't use a camera anymore cause it's one more distraction while I'm trying to get ready.
As for the thermostat, cutting the guts out usually leaves enough backpressure for the water pump so it doesn't cavitate- that's one of the big issues in the car not cooling when you start yanking thermostats. that's specifically why I said not to remove the entire thing. Most road racers with built engines just run a blocking plate with an orifice the size of an OE thermostat with the guts removed.
Increasing the FLOW of water through an engine can only help. "it doesn't have enough time to absorb heat" is foolishness at its best. One particular 1oz section of coolant may only go up 5-10 deg while it's in the engine, but it's followed by another 1oz of coolant coming in cooler and going out hotter.
then it goes through the radiator and cools down. spends less time in the radiator so it cools less? so what. there's another 1oz of water right behind it that gets cooled down too.
The only thing you're doing by increasing water flow through the engine is equalizing the temps more between the engine and radiator.
A slow water flow will provide a higher change in temp of the coolant, but you're still moving the same amount of BTUs around.
1 gal/min at 30 deg difference moves just as much heat at 3 gal/min at 10 deg difference.
Again, the big difference between the two systems is how well the water pump works. If you have zero pressure in the system, it's easier for the vanes of the pump to cavitate while spinning at high rpm. thus you need some sort of restrictive orifice near the OEM thermostat size if you're running an OEM pump designed around that sizeand thus flowrate.
If you change to an aftermarket water pump designed for higher RPM use, the vanes will be different on the impeller that change the flow characteristics at high rpm and you can usually yank the thermostat altogether.
However, on a street car that sees everything from 30F to 220F coolant temps, then you should have a thermostat to regulate the temp.
But to simplify the diagnosis process when you have cooling problems while it's 90 deg outside, you can remove the thermostat guts and remove one variable from the equation. With these outside temps, you don't have to worry about running the engine too cold.
http://forums.maxima.org/autocrossin...ake-stuff.html
Some video of a race in Jan with a cold, wet track... you can see how slippery it is in the vids. fawk I hate running that track in the rain!
http://www.youtube.com/watch?v=MkT3QbD_r7s
I can't find the vids of some of my other races since I'd borrowed a friend's camera and he did the uploads. don't use a camera anymore cause it's one more distraction while I'm trying to get ready.
As for the thermostat, cutting the guts out usually leaves enough backpressure for the water pump so it doesn't cavitate- that's one of the big issues in the car not cooling when you start yanking thermostats. that's specifically why I said not to remove the entire thing. Most road racers with built engines just run a blocking plate with an orifice the size of an OE thermostat with the guts removed.
Increasing the FLOW of water through an engine can only help. "it doesn't have enough time to absorb heat" is foolishness at its best. One particular 1oz section of coolant may only go up 5-10 deg while it's in the engine, but it's followed by another 1oz of coolant coming in cooler and going out hotter.
then it goes through the radiator and cools down. spends less time in the radiator so it cools less? so what. there's another 1oz of water right behind it that gets cooled down too.
The only thing you're doing by increasing water flow through the engine is equalizing the temps more between the engine and radiator.
A slow water flow will provide a higher change in temp of the coolant, but you're still moving the same amount of BTUs around.
1 gal/min at 30 deg difference moves just as much heat at 3 gal/min at 10 deg difference.
Again, the big difference between the two systems is how well the water pump works. If you have zero pressure in the system, it's easier for the vanes of the pump to cavitate while spinning at high rpm. thus you need some sort of restrictive orifice near the OEM thermostat size if you're running an OEM pump designed around that sizeand thus flowrate.
If you change to an aftermarket water pump designed for higher RPM use, the vanes will be different on the impeller that change the flow characteristics at high rpm and you can usually yank the thermostat altogether.
However, on a street car that sees everything from 30F to 220F coolant temps, then you should have a thermostat to regulate the temp.
But to simplify the diagnosis process when you have cooling problems while it's 90 deg outside, you can remove the thermostat guts and remove one variable from the equation. With these outside temps, you don't have to worry about running the engine too cold.
Last edited by Matt93SE; 05-24-2011 at 10:08 AM.
05-24-2011, 11:19 AM
#9
Supporting Maxima.org Member
Thread Starter
iTrader: (9)
Join Date: Oct 2003
Location: Austin, TX
Posts: 1,232
Is there any chance that a blocked jiggle valve would cause these problems? My understanding is that it allows a bit of coolant/air past the thermostat so it doesn't act like a brick wall when closed. If that were blocked, could the thermostat trap a big bubble of air behind it causing the hot coolant to flow around the wax housing?
I don't think any silicone got on it that would block it during installation, but it seemed like a super-small opening for anything to pass though. Would drilling a 1/8" hole through the housing next to the jiggle valve cause problems (assuming that is the cause for it not opening properly)?
I don't think any silicone got on it that would block it during installation, but it seemed like a super-small opening for anything to pass though. Would drilling a 1/8" hole through the housing next to the jiggle valve cause problems (assuming that is the cause for it not opening properly)?
05-24-2011, 12:17 PM
#10
Member
Join Date: Sep 2002
Posts: 161
Brad92SE,
I'd just replace the thermostat - it's obviously not working properly. I've had one 'stick' before on a Mitsubishi Eclipse - brand new from the box. Exact same symptoms - ran up way too hot during warmup, then when the t-stat finally opened, everything was o.k. Drilling extra holes, or gutting the thermostat doesn't really solve your problem. At best it's a band aid. Add to that it'll probably take more time, and how much more money is it going to cost you to just replace it?
I'd just replace the thermostat - it's obviously not working properly. I've had one 'stick' before on a Mitsubishi Eclipse - brand new from the box. Exact same symptoms - ran up way too hot during warmup, then when the t-stat finally opened, everything was o.k. Drilling extra holes, or gutting the thermostat doesn't really solve your problem. At best it's a band aid. Add to that it'll probably take more time, and how much more money is it going to cost you to just replace it?
05-24-2011, 08:08 PM
#12
Senior Member
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
Increasing the FLOW of water through an engine can only help. "it doesn't have enough time to absorb heat" is foolishness at its best. One particular 1oz section of coolant may only go up 5-10 deg while it's in the engine, but it's followed by another 1oz of coolant coming in cooler and going out hotter.
then it goes through the radiator and cools down. spends less time in the radiator so it cools less? so what. there's another 1oz of water right behind it that gets cooled down too.
The only thing you're doing by increasing water flow through the engine is equalizing the temps more between the engine and radiator.
A slow water flow will provide a higher change in temp of the coolant, but you're still moving the same amount of BTUs around.
1 gal/min at 30 deg difference moves just as much heat at 3 gal/min at 10 deg difference.
Again, the big difference between the two systems is how well the water pump works. If you have zero pressure in the system, it's easier for the vanes of the pump to cavitate while spinning at high rpm. thus you need some sort of restrictive orifice near the OEM thermostat size if you're running an OEM pump designed around that sizeand thus flowrate.
If you change to an aftermarket water pump designed for higher RPM use, the vanes will be different on the impeller that change the flow characteristics at high rpm and you can usually yank the thermostat altogether.
However, on a street car that sees everything from 30F to 220F coolant temps, then you should have a thermostat to regulate the temp.
But to simplify the diagnosis process when you have cooling problems while it's 90 deg outside, you can remove the thermostat guts and remove one variable from the equation. With these outside temps, you don't have to worry about running the engine too cold.
+1 on all of that....................
Is there any chance that a blocked jiggle valve would cause these problems? My understanding is that it allows a bit of coolant/air past the thermostat so it doesn't act like a brick wall when closed. If that were blocked, could the thermostat trap a big bubble of air behind it causing the hot coolant to flow around the wax housing?
I don't think any silicone got on it that would block it during installation, but it seemed like a super-small opening for anything to pass though. Would drilling a 1/8" hole through the housing next to the jiggle valve cause problems (assuming that is the cause for it not opening properly)?
I don't think any silicone got on it that would block it during installation, but it seemed like a super-small opening for anything to pass though. Would drilling a 1/8" hole through the housing next to the jiggle valve cause problems (assuming that is the cause for it not opening properly)?
From your description of the problem I would say you have a funky new stat (assuming you have bled the thing properly, the rad and expansion tank are both filled properly, the radcap is working as it should, and you are not losing ANY coolant between hot/cold cycles).
As for "upgrading" stats - I just cannot see the need for that. You have yourself proven that your car's cooling system used to do the job properly till "something" started acting up again - find the "something" and as Matt suggested, the stat is the obvious and absolute easiest to start with - either by way of replacement or temporarily removing to troubleshoot.
Last edited by LvR; 05-24-2011 at 08:10 PM.
05-24-2011, 08:19 PM
#13
just don't run a thermostat... that's what i do no over heating problems, + it makes you warm your car up b4 you go ripping on it b4 she's warm i bypassed my heater core as well, i didn't know which was the problem so no its fixed and she doesn't over heat
no over heating problems, + it makes you warm your car up b4 you go ripping on it b4 she's warm i bypassed my heater core as well, i didn't know which was the problem so no its fixed and she doesn't over heat
05-24-2011, 09:28 PM
#14
Senior Member
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
ITO a fault-finding method (stat removed) that's fine, but mechanical durability of the motor suffers as a result of that if its a permanent situation - with a stat in the motor you can probably guaranteed reach proper operating temp in about 1-2 km with very little effort ................. with no stat - my guess is 10km+ .............. if ever ?
05-25-2011, 03:37 PM
#15
ITO a fault-finding method (stat removed) that's fine, but mechanical durability of the motor suffers as a result of that if its a permanent situation - with a stat in the motor you can probably guaranteed reach proper operating temp in about 1-2 km with very little effort ................. with no stat - my guess is 10km+ .............. if ever ?
05-26-2011, 05:28 AM
#19
Supporting Maxima.org Member
Thread Starter
iTrader: (9)
Join Date: Oct 2003
Location: Austin, TX
Posts: 1,232
My heater does run hot, but wouldn't that indicate it isn't blocked? The temp gauges do the same thing (no reading on autometer, close to 'H' on the dash) until the system starts circulating regardless if I turn the climate control to cold or hot. The Z has an automatic valve that closes off the heater core flow when the climate control is set to cold.
05-26-2011, 07:20 AM
#20
Senior Member
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
My heater does run hot, but wouldn't that indicate it isn't blocked? The temp gauges do the same thing (no reading on autometer, close to 'H' on the dash) until the system starts circulating regardless if I turn the climate control to cold or hot. The Z has an automatic valve that closes off the heater core flow when the climate control is set to cold.
However - first confirm you are not losing any coolant at all during a hot/cold cycle
05-27-2011, 07:30 PM
#21
Supporting Maxima.org Member
Thread Starter
iTrader: (9)
Join Date: Oct 2003
Location: Austin, TX
Posts: 1,232
Well tonight I tried burping the cooling system again, I sat idling on a hill for around an hour, and the thermostat never opened. I got some air out of the system... but I think thats a pretty solid indicator that I got a dud OEM thermostat. 
It did open once I started driving a bit, the temp gauge went to a little more than half before it did. Gonna go to the dealer and get another stat in the morning and tear into it again 
.
It did open once I started driving a bit, the temp gauge went to a little more than half before it did. Gonna go to the dealer and get another stat in the morning and tear into it again .
05-28-2011, 09:51 AM
#22
Supporting Maxima.org Member
Thread Starter
iTrader: (9)
Join Date: Oct 2003
Location: Austin, TX
Posts: 1,232
Well I bought a new thermostat and checked both the new and old in boiling water. They both opened at the same time, ~190°F. Both of them looked like they had the same amount of travel.
Is it possible for a thermostat to work out of the car but not in it? I can't think of any reason why things would change. The bypass hose is connected correctly, from the lower IM to the T-stat housing and isn't kinked. I couldn't feel anything inside of the housing that would cause a blockage or prevent the stat from opening. Any thoughts?
Is it possible for a thermostat to work out of the car but not in it? I can't think of any reason why things would change. The bypass hose is connected correctly, from the lower IM to the T-stat housing and isn't kinked. I couldn't feel anything inside of the housing that would cause a blockage or prevent the stat from opening. Any thoughts?
05-28-2011, 12:49 PM
#23
Are you using the Z or VE radiator? Did you have to do any custom radiator hoses or anything like that?
I wonder if maybe the different position(s) of hoses/radiator placement in relation to the engine or something could somehow cause any goofy coolant problems?
Or maybe Austin just hates thermostats. My buddy went down to Austin a few weeks ago for a conference and had his Civic overheat and die and puke coolant everywhere at his hotel after sitting in traffic. It turns out his thermostat randomly stuck closed
I wonder if maybe the different position(s) of hoses/radiator placement in relation to the engine or something could somehow cause any goofy coolant problems?
Or maybe Austin just hates thermostats. My buddy went down to Austin a few weeks ago for a conference and had his Civic overheat and die and puke coolant everywhere at his hotel after sitting in traffic. It turns out his thermostat randomly stuck closed
Last edited by James92SE; 05-28-2011 at 12:51 PM.
05-28-2011, 04:45 PM
#24
Supporting Maxima.org Member
Thread Starter
iTrader: (9)
Join Date: Oct 2003
Location: Austin, TX
Posts: 1,232
Are you using the Z or VE radiator? Did you have to do any custom radiator hoses or anything like that?
I wonder if maybe the different position(s) of hoses/radiator placement in relation to the engine or something could somehow cause any goofy coolant problems?
Or maybe Austin just hates thermostats. My buddy went down to Austin a few weeks ago for a conference and had his Civic overheat and die and puke coolant everywhere at his hotel after sitting in traffic. It turns out his thermostat randomly stuck closed
I wonder if maybe the different position(s) of hoses/radiator placement in relation to the engine or something could somehow cause any goofy coolant problems?
Or maybe Austin just hates thermostats. My buddy went down to Austin a few weeks ago for a conference and had his Civic overheat and die and puke coolant everywhere at his hotel after sitting in traffic. It turns out his thermostat randomly stuck closed
I wouldn't be surprised if there are some trapped pockets of air the way things are routed. The lower IM outlet is a tad higher than the radiator fill point. I spoke with Matt this afternoon, and he had some good ideas like using a vacuum pump on the bleeder screw. I did that when refilling today, and got quite a few bubbles out. I'll see tomorrow morning how it runs!
Austin probably does hate thermostats... I didnt have any issues until I moved here and it started getting hot as hell out.
Last edited by Brad92SE; 05-28-2011 at 04:48 PM.
05-28-2011, 07:27 PM
#25
I'm using the Z radiator, which is the same as the VE one but just over half as thick (fail). It is a brand new Koyo though. I custom fit all of the hoses, and the radiator outlet hose is long since it goes all the way to the back of the engine where the t-stat housing is.
I wouldn't be surprised if there are some trapped pockets of air the way things are routed. The lower IM outlet is a tad higher than the radiator fill point. I spoke with Matt this afternoon, and he had some good ideas like using a vacuum pump on the bleeder screw. I did that when refilling today, and got quite a few bubbles out. I'll see tomorrow morning how it runs!
Austin probably does hate thermostats... I didnt have any issues until I moved here and it started getting hot as hell out.
I wouldn't be surprised if there are some trapped pockets of air the way things are routed. The lower IM outlet is a tad higher than the radiator fill point. I spoke with Matt this afternoon, and he had some good ideas like using a vacuum pump on the bleeder screw. I did that when refilling today, and got quite a few bubbles out. I'll see tomorrow morning how it runs!
Austin probably does hate thermostats... I didnt have any issues until I moved here and it started getting hot as hell out.
Welcome to Texas (hottest spot in the nation) 
05-28-2011, 08:17 PM
#26
Senior Member
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
I'm using the Z radiator, which is the same as the VE one but just over half as thick (fail). It is a brand new Koyo though. I custom fit all of the hoses, and the radiator outlet hose is long since it goes all the way to the back of the engine where the t-stat housing is.
I wouldn't be surprised if there are some trapped pockets of air the way things are routed. The lower IM outlet is a tad higher than the radiator fill point. I spoke with Matt this afternoon, and he had some good ideas like using a vacuum pump on the bleeder screw. I did that when refilling today, and got quite a few bubbles out. I'll see tomorrow morning how it runs!
Austin probably does hate thermostats... I didnt have any issues until I moved here and it started getting hot as hell out.
I wouldn't be surprised if there are some trapped pockets of air the way things are routed. The lower IM outlet is a tad higher than the radiator fill point. I spoke with Matt this afternoon, and he had some good ideas like using a vacuum pump on the bleeder screw. I did that when refilling today, and got quite a few bubbles out. I'll see tomorrow morning how it runs!
Austin probably does hate thermostats... I didnt have any issues until I moved here and it started getting hot as hell out.
05-29-2011, 12:47 AM
#27
Jack your car's front end up, place an old oil container or windshield washer bottle into your radiator filler neck and cut the bottom off the bottle, fill with coolant/water and run engine until there are no bubbles showing up in you water column!
05-29-2011, 08:54 PM
#28
Supporting Maxima.org Member
Thread Starter
iTrader: (9)
Join Date: Oct 2003
Location: Austin, TX
Posts: 1,232
Today I finally got it working well. I ended up sticking a vacuum pump on the bypass hose between the radiator inlet and water pump, and sucked all the air I could from those parts. I jacked the front end way up and got the thermostat to open and enough air out of the system so that it circulates properly. I did have to shut the heater fans off to get the temp up enough for the stat to open though.
I drove out to College Station this afternoon (~2hrs) in close to 100 degree heat and the temp was rock solid at 190. During stops it never got over 210-ish. Thanks for all of the help and suggestions!
I drove out to College Station this afternoon (~2hrs) in close to 100 degree heat and the temp was rock solid at 190. During stops it never got over 210-ish. Thanks for all of the help and suggestions!
05-29-2011, 09:41 PM
#29
Senior Member
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
Today I finally got it working well. I ended up sticking a vacuum pump on the bypass hose between the radiator inlet and water pump, and sucked all the air I could from those parts. I jacked the front end way up and got the thermostat to open and enough air out of the system so that it circulates properly. I did have to shut the heater fans off to get the temp up enough for the stat to open though.
I drove out to College Station this afternoon (~2hrs) in close to 100 degree heat and the temp was rock solid at 190. During stops it never got over 210-ish. Thanks for all of the help and suggestions!
I drove out to College Station this afternoon (~2hrs) in close to 100 degree heat and the temp was rock solid at 190. During stops it never got over 210-ish. Thanks for all of the help and suggestions!
Makes me wonder though - different water pump designs to blame? .................. crank pulley diameter differences?
Back to the original problem description - if it was working properly at some stage for a few days, what exactly made this issue re-appear if you didn't lose any coolant? You sure you have a solid radcap and overflow bottle with connecting hose in good condition? Just me, but I wouldn't trust the thing till one can explain why this problem returned in the first place.
05-29-2011, 11:02 PM
#31
Senior Member
Join Date: Oct 2004
Location: Pretoria - South Africa
Posts: 1,205
I was actually thinking more about the differences in 3rd gen filling characteristics between 2 supposedly identical set-ups, but yeah, in general, as long as the aero properties of the nose of the car dictates the radiator to be much lower than the top of the engine and also way lower than the top of the in-cab heat-exchanger, life is going to be very difficult.
Me? - I would add a simple filler to the top of the in-car heat exchanger and bring it out to the engine bay where the filling can be ensured to happen easily and properly. Its why I love the VW set-ups where there is a closed (no rad-cap) radiator and permanent forced circulation through the expansion tank where the filling is made to happen - generally higher than the top of the motor
Me? - I would add a simple filler to the top of the in-car heat exchanger and bring it out to the engine bay where the filling can be ensured to happen easily and properly. Its why I love the VW set-ups where there is a closed (no rad-cap) radiator and permanent forced circulation through the expansion tank where the filling is made to happen - generally higher than the top of the motor
05-30-2011, 06:50 AM
#32
Supporting Maxima.org Member
Thread Starter
iTrader: (9)
Join Date: Oct 2003
Location: Austin, TX
Posts: 1,232
Strange how some of these motors need an extraordinary amount of coaxing to get all the air out while others you can simply fill and drive with no hassles at all .................... sure glad mine is one of the easier ones.
Makes me wonder though - different water pump designs to blame? .................. crank pulley diameter differences?
Back to the original problem description - if it was working properly at some stage for a few days, what exactly made this issue re-appear if you didn't lose any coolant? You sure you have a solid radcap and overflow bottle with connecting hose in good condition? Just me, but I wouldn't trust the thing till one can explain why this problem returned in the first place.
Makes me wonder though - different water pump designs to blame? .................. crank pulley diameter differences?
Back to the original problem description - if it was working properly at some stage for a few days, what exactly made this issue re-appear if you didn't lose any coolant? You sure you have a solid radcap and overflow bottle with connecting hose in good condition? Just me, but I wouldn't trust the thing till one can explain why this problem returned in the first place.
I do like the idea of a fill point that is relocated to the highest point.
05-30-2011, 07:49 AM
#33
the 6th gen Max is the same way. FSM procedures to bleed their system include a vacuum pump. that's where I came up with the idea for Brad and it seemed to work!
and I now have a sweet vacuum pump to use for... 
Thread
Thread Starter
Forum
Replies
Last Post
tarun900
4th Generation Maxima (1995-1999)
19
12-20-2021 06:57 PM