maxinout93

i have an 02 i35. Lately ive had to do some cooling system repairs and noticed the overflow tank fills up to the top with antifreeze like all the coolant is flowing into it but not being sucked back into the engine when i shut it off. Had a pressure test done where the heater hose connection was leaking under pressure, so I bypassed the heater core. Weeks later one of the throttle body coolant passages developed a long crack dumping all the antifreeze out, it was damaged already but i never replaced it, so i ended up replaceing it. Next one of the radiator fans went out on pass side, so i had to remove the upper radiator hose twice to replace it. Did not bleed the system and the car is not running hot, but its making me a little nervous that i have to either add coolant from the overflow tank back in the radiator or add it from a bottle, although not very much im assuming bacause of the work i did each time resulted in coolant leaking on the ground. Im hoping i dont have a cracked block or something like that like someone said may have a pinhole size leak. idk. They sugguested i use some stuff in walmart called K-seal? Im confused. i drive the car about 250 miles or more every weekend.

maxiiiboy

Don't use any sealant. Fill it with coolant and burp it, thoroughly. Before doing any repairs, find what your problem is, if any.

mclasser

A faulty radiator cap can mess up the rad-reservoir coolant exchange. Replace with an OEM cap and report back.

wellshii19

What the guys said above.
Honestly do the hoses too if not already done. If they feel really soft to the touch,
they'll probably give out on you as well. Time consumes parts the way my wife consumes my patience.
if your worried about a cracked block,check your oil.
I doubt it though.

maxinout93

I noticed different radiator caps make the car run different. I get alot of my caps from the junk yard. Gonna see if it does the same with another cap

maximatech12

Maybe you have stop leak plugging the fins up?
Pulling the radiator is easy. It's just the mounts two fan motor connectors, radiator hoses then ATF cooler lines.
What I guess you could do is try back flushing it.

​​​​​​

maxinout93

well i did bleed the coolant today up on a ramp and let it do its thing. Both fans come on low speed and cool the car off. I let it cycle about three times while adding more coolant until i only saw very few air bubbles. I still have a constant misfire at idle, and i can kinda feel bursts of power while driving, like it will lag and then pick up power from somewhere. But drove for 2 hours, put OE radiator cap on, and came to a stop to check overflow. It was still in the same spot just with small amount of bubbles. I replaced radiator last year and coolant is green. SO im not sure if its clogged from stop leak. So many issues here and its not throwing a check engine light smh, no oil mixing with coolant and no overheating. Im thinking i should take it to the dealer to find out what is wrong, but i dont know what that will cost.

wellshii19

Burst of power? Sounds like a fuel issue,not a coolant issue.
If it's misfiring,that's air to fuel problem.
When were the plugs changed? Coil packs?
Fuel filter? Yes Nissan says fuel filter is lifetime,but that's BS as with any fluid or filter.
Wonder what your fuel pressure is.

maxinout93

changed the rear plugs and coils recently about 2 months ago, the front checked out ok so i didnt bother those because they were done about 2 years ago ngk platinum. I didnt know there was a fuel filter on these cars. Ive never touched that. Currently monitoring the coolant system overflow and it seems to be sucking in some from there but will keep an eye on it.

wellshii19

Change out the fuel filter.
I actually just changed mine because I didnt know the service records on it.
Sure enough,the little hint of stumbling I had(very subtle) is gone.
Yes all cars have fuel filters. Just depends on the manufacturer if they want to put it on the service intervals. (marketing tool to get people to buy cars)

Change plugs always at the same time just as anything else.

maxinout93

Does that mean changing the fuel pump also? Can u buy the filter separately? Where is it? Coolant seems to be staying steady so far after bleeding and the $16 oem cap.

wellshii19

At least your good with the coolant issue.
Fuel filter: O-Ring to replace with it: Link showing how to change it:
http://www.shiftice.com/fuel_filter.html

Honestly at that point ,it's good to check your fuel pressure to see if your in spec to see how the fuel pump is doing.
Nissan has certain adapters to check fuel pressure but I couldn't find them .
A bosch pump is 60 bucks,others will vary(on amazon)

maxinout93

Well things dont look too good as its doing the same thing. I see it mainly does it if im going highway speeds of 70 mph plus for about an hour to 2 hours non stop. Before leaving on a trip today I checked radiator and it was full. Resorvior was a little below the max line. So after an 2 hour drive I get where im going shut the car off and the resorvior is almost full to the top? Now I did bypass the heater core. But the radiator was almost empty. Im thinking how much longer with this car.

MichMaxFan

Your coolant issue is interesting to say the least and I'm no professional but in my opinion...

I would document every trip length, every mileage, every speed, etc to prove exactly when it acts up, with no uncertainty. It appears from what you say that this might be achievable since the car seems a bit predictable to you.

​​​It seems the only key concerns should be temp, volume, pressure, and air in the system. It sounds like rpm is the determining factor because that is the only difference I can think of due to long driving at high speed.

I wonder if it's a head gasket issue but that seems like it would show symptoms at any speed. Can you get it pressure tested?

The level in the overflow will rise about half inch or so when coolant is hot, not as much as it seems on your car.

maxinout93

Yeah its weird and it just started doing this around Jan. With the shake at a stop etc.I had it pressure tested last month after a 250 mile trip of highway driving and as soon as I got off the freeway to get gas I noticed the temp hand rising so I shut it off for 30 mins. Radiator was about empty but overflow was full so thought it was a bad cap. On the way home same scenario 250 mile trip 70 plus mph get off the rd, needle started to rise so turn it off. Local shop pressure tested it. It was dropping and leaking from the top heater hose at heater core, so I bypassed that. It seems to act normal around town with a mix of city and highway driving, coolant gets sucked in the overflow and it may go up or down an inch or so,that's why in an earlier post I thought everything was ok.now I replaced the radiator,thermostat, water pump, and fans, but for some reason traces of some Orange stop leak find it's way into the radiator even after a shop supposedly flushed the system prior to installing a new radiator.

wellshii19

Did you check if you had coolant in your oil?
Seems like a bad head gasket.
Who did all the work?(pump ,etc)

wellshii19

Also like the post said earlier,don't use stop leak. Now it's probably clogging your radiator and pushing it back into the reservoir. Gonna have to do it all over again.

maxinout93

no there is no coolant in the oil and no white smoke, and for the most part no overheating. When i bought the car 2 years ago the previous owner must have used the stop leak. But i didnt think nothing of it as the car ran good.

maxinout93

a shop did the water pump back in october as it was overheating just after about 20 mins of driving. I did the radiator, thermostat, coolant lines myself. Took it to a shop for them to flush it.

maxinout93

so you think that the radiator is clogging with stop leak after a long drive without the fans moving the coolant? Im gonna stop by a shop today and see what they say. man this car is driving me crazy lol.

wellshii19

Possibly. Either that or a head gasket man. Bad head gasket will do that. Also your oil may be clean but the head gasket can still be cracked.
I'm really curious as to how the rear plugs look right about now.

maximatech12

when you flush the coolant how much did you put In?
In my 3.0 The system takes approx 8quarts of 50/50.

​​​​when I drain the radiator I get close to 3-4 quarts. So there's another 4-5 quarts in the system.
theres a bit of math involved so somehow maybe you got the levels wrong.

maxinout93

When I took the original rear plugs out 2 had kind of a thick orange coating on the tip. But I did get a check engine light for those 2

wellshii19

Ok that's your problem.
Originally the head gasket started to crack ,someone sealed it up instead of doing it the right way,and the problem was passed on to you.
Only god knows how much of that stuff held up.You should have changed the rear plugs before.

Child_uv_KoRn

iTrader: (7)

They overheated it and warped the heads. HG itself isn't going to actually fail as it's multilayer steel.


As long as coolant doesn't go into the cylinders, you're still OK as far as milking life out of the engine. What's happening is the exhaust gasses are forcing the coolant out, then it's full of air, and you'll overheat. To remedy this cut the bottom of the rad cap off or get a flat one (no spring and lower seal). This will allow the gasses to escape, so your cooling system stays full. I would keep sealant in the system (K-seal is known to work very well).

As long as the sealant holds you can get a lot of life out of it (which is why you leave it full of good sealant. It will continually reseal any spots that blow out).

maxinout93

I changed the rear plugs about 2 years ago when i originally bought the car, only the front plugs were new. Since then ive put about 30k miles on the car, when i recently replaced the rear plugs again.

maxinout93

Thanks for the much needed advice man and sorry for the late response, been very busy. The first set of plugs that i changed when i bought the car on the rear had the orange or yellow residue on the tips, i thought i might have came from a pre cat that was damaged or something. So your theory would possibly explain why i never got heat while sitting at idle possibly. I did drain and flush the radiator of the stop leak that was in there, and most made its way to the coolant resorvior and settled in the bottom. I cleaned that also. So where do i get a cap that is flat? Ive got several radiator caps just sitting around. K-seal do i just pour that into the radiator with the antifreeze thats already in there?

maxinout93

Update. Well after adding the k-seal like child of corn suggested( i only added a little at a time. the coolant has not been disappearing like it used to. I used to go only about 2 hours of highway driving before i noticed the antifreeze would be filled to the top of the coolant tank and the car would feel sluggish. THis weeknd i took the car on a 8 hour straight drive with a few stops to be sure things were ok. there were no bubbles in the coolant tank and the radiator still had coolant in it. wow still have the instances of misfireing at idle or at a stop but not too worried about that.

maxinout93

Where do I get a radiator cap with no lower seal like you are suggesting. Do u have a picture of one. Seems as if this scenario maybe occurring because I recently had a coolant hose burst while going down the highway about 2 days ago. It was a small rubber hose that connects the 2 coolant pipes near the head. Looks almost like someone took a knife to it.

maxinout93

I'm not sure if this is another possible source of a leak. The area is always damp. This is near the coolant pipe closest to the firewall.

maximatech12

Head gasket is a big job!
Have you tried a compression test?

maxinout93

no i havent tried the compression test. Im not so sure its the head gasket though. Ive found a possible source of a leak so just to be sure im gonna get anther pressure check done to be sure its leaking from the coolant pipe connection at the head. Im about ready to throw another motor in soon if it is something major.

maxinout93

Just wanted to give an update as of today. I had a bad radiator, coolant was seeping out from the fin area at the top. I guess you get what you pay for from ebay. Radiator didnt last a year. That seemd to be the problem. I had to add coolant almost everyday until i actually say the seam in the radiator coming apart. Long story short I replaced the radiator, took several long trips, and the coolant was still full inside the radiator, and also the overflow tank is not overflowing, and the system is sucking the coolant back in from the overflow tank at cool down. Ill keep my fingers crossed still but things seem good so far and its been over 2 months, and I drive this car every weekend 250 miles or more on the highway. Thanks for everyones advice, currently at 236K miles.

maximatech12

What type anti-freeze have you been running?
When I bought this Maxima they had Green running through it!
I eventually found issues with the Green coolant.
Not sure what temp the Maxima is designed to run at but I know if you run Green the temp won't stabilize.
It will be at 210 then dive down to 199 Then back up to 203.

MichMaxFan

Didn't nissan oem come as a green coolant? Maybe I am wrong but maybe there is good green and a cheap green? Maybe not...just wondering.

I use Toyota ext life red and no problems so far. I drain and fill every 12000-15000miles, or there abouts. Might be overkill but at least I should not ever have acid problems. Need to learn how to test acidity reliably.

maximatech12

I don't know maybe it was Green I was under the impression it was Blue.
I wouldn't use Toyota RED either.
The coolant is designed to cool the cylinders and stabilize the temps.
Toyota may have different thermostats in different location, different radiator, and different cooling system.
So the Toyota Red may not cool the Nissan properly.
I doubt it would damage the head gasket but running at 210 seems too hot for this car.
I would imagine the Temp is supposed to stabilize at 203 since that's what the upper thermostat is rated at.
I got this one with Green and had mounds of corrosion build up at the coolant inlet/outlets.

maximatech12

I did see Nissan had a Green coolant available but I just assumed it was for topping off.

maxinout93

Ive been using green coolant and sometimes used coolant from the pull-a-part.

maximatech12

I want the good Green! Does this stabilize the temp or is it supposed to be all over between 190-210?
If your overflow tank is filling up with coolant it could be the lower (180 degree) thermostat is bad.

DennisMik

iTrader: (2)

The specification for the thermostat is that it opens at 180º F. The fact that the coolant temperature varies is due to the ECU turning the radiator fans on and off. The only thing I wonder about is the high point of the temperature range. If the car is sitting there idling, the high temp should be 203º to maybe 205º. But 210º isn't that far off.

Based on the numbers, this should not be causing the coolant to go into the reservoir.

Maybe you should look at the ECTS temperature sensor. Maybe it registers low. When the engine is cool, like in the morning, read the temperature. Just turn the ignition key to the ON position, you don't have to start the car. The temperature reading should be whatever the air temperature is.

The type of antifreeze you use won't have any bearing on this. Antifreeze is to raise the boiling point of the water, lubricate the water pump and prevent electrolytic corrosion of the metal parts of the engine. The color just indicates the chemical type of how it does these things. Green antifreeze is type IAT - Inorganic Acid Technology. Orange, red, green, pink or blue antifreeze is OAT type - Organic Acid Technology. Yellow or orange (yes, duplication of color) is type HOAT - Hybrid Organic Acid Technology.

You can mix the different types to a limited extent. I admit I don't fully understand the why and why not of this but don't do a 50/50 mixture of 2 different types.

And for what it is worth, the color is not an ironclad guarantee that 2 brands of the same color antifreeze are of the same chemical type. There is no mandatory requirement that, for example, an IAT antifreeze be green. We already see this in orange antifreeze.