My 95 maxima does not heat up while driving, but heats up if it is standing. So, I went to a Mechanic today and he told me that it would cost me $150 for changing the thermostat. I was under the impression that the thermostat was on the passenger's side of the engine. But, according to the mechanic, that was the lower hose. The upper hose, where the thermostat is connected is way inside on the driver's side of the engine.

It seems odd to me that the thermostat would be placed so far inside that you have to take half the engine apart to reach it.

Anyone ideas/info will be appreciated.

Thanks.

 

That's funny. Get a manual and check it out. What is this about the lower hose? Follow the top hose and that will lead to thermostat. That is what i always thought and have been told.

 

The thermostat housing is located at the engine end of the lower radiator hose. The factory service manual gives these instructions for removal and installation.

1) Drain coolant from drain plugs on radiator and both sides of cylinder block.

2) Remove drive belts and idler pulley bracket.

3) Remove water pump drain plug on pump side of cylinder block.

4) Remove lower radiator hose.

5) Remove water inlet and thermostat assembly. Do not disassemble water inlet and thermostat. Replace them as a unit, if necessary.

6)Install thermostat with jiggle valve facing upward. After installation, run engine for a few minutes, and check for leaks. Be careful not to spill coolant over engine compartment. Use a rag to absorb coolant.


After reading all this, I looked under the hood of my '99 GXE. The job looks even easier than the manual's procedure. I can't see any reason to carry out steps 2 and 3. The belts and pulley aren't in the way. This job does not involve jacking the car and does not require any special tools. It could be done by a home mechanic.

 

From 95 svc manual pg. LC-13: The thermostat is located behind the water inlet which is under the timing chain cover immediately below the engine oil fill cap and just above the alternator. The inlet being on the front of the motor and the hose connects to the bottom radiator port. The manual states "Do not disassemble water inlet and thermostat. Replace them as a unit, if necessary." and install the thermostat with the jiggle valve facing upward.

Maybe that's why they're asking for so much to replace the thermostat. But the labor should not be very much, it's easy to get to from above the car. Manual says to remove the lower radiator hose. This is probably to keep from getting antifreeze into the alternator and other parts b/c it looks like it will come right out by just removing the hose connection from the water inlet.

Hope this helps.

 

The 95 manual does not call for the water pump and pulleys to be removed. Looks like Nissan has tried to make the procedure more complicated than it really is. Probably to justify charging more for the procedure. I can see how someone might want to charge 150 if they had to remove the water pump and pulleys etc.

 

 

and sometimes it idles at 2500rpm my dad sd its ok ....is it

 

Get the thermosat fixed then find the idle problem.

Mike S.

 

my car gets warm and to normal operating temp when its still like the other guy who posted this topic but when im on the go and the heat is on at full blast the temp goes down to cold and somtimes when im at a light the car idles at 2000rpms but when i turn off the heat it stops is this the same thing the guy is talking about

 

please answer my late post

 

change the thermostat, then deal with the idle problem if it's still there. one thing at a time.

 

Yeah, change the thermostat. I'm gonna change mine on Tuesday.

 

Debajits - your stat is sticking open. I've had this problem 3 times before on my 95SE. If you have the oem stat in you may notice a rubber seal on its circumference has slipped off preventing it from closing all the way (therefore the cold engine temps). On my last trip to the parts store, I decided to skip the dealer. This current stat has no rubber seal.

I wish I could say that it has worked out well, but just today I noticed that it was running cold again. This one has lasted about 4 months. I'm thoroughly flustered. Thermostats don't tend to be this problematic.

DBM, can you lend some sanity to this confounding problem? The car is totally stock. I can't imagine what is causing this.

Has anyone else experienced thermo failures?

 

Yeah, mine has started to go bad this month. I'm gonna get it replaced on Tuesday. Apparently, when the car is running cold due to the bad thermostat, the ECU reads it as a cold-start condition the entire time and continues to run a very rich mixture (as it normally does for cold starts), which means bad gas mileage and possibly fouling of combustion chamber and exhaust parts.

 

As a sanity check, could you take a read on my last post? (see above) I'm beside myself on what could be causing this on such a run-of-the-mill part. This is my 3rd stat and this one looks like it is very sluggish to react. I'm thinking that it may be on its way out. I don't think I've replaced 3 stats in the last 15 years! I appreciate whatever help you can provide.

95SE 5sp, 110K miles, all stock, using Prestone antifreeze

 

I didn't respond earlier because I don't have a good "fix" to offer. I still don't. This post offers some ideas for your consideration.

When you replaced your thermostats did you replace the 'stat and housing as a unit? That's what the factory service manual calls for, though it doesn't explain why. If you replaced the 'stat only, did you orient it with the jiggle valve "up"? That is important.

Did you test the bad 'stats in a pan of water heated on the kitchen stove? This would give an idea of whether the 'stat was truly bad or the problem is elsewhere.

Air pockets trapped in the cooling system can cause trouble. Some engines have cooling system bleeder screws to get that air out, but I don't believe the 4Gen Maxima does. You might resort to jacking the front of the car as high as possible and idling the engine for 15 minutes with the heater on Maximum. Turn the engine off and let it cool. Remove the radiator cap and inspect. If there is any headroom, add coolant. Repeat until no headroom remains.

 

Yes, it was replaced as a unit. The reason for replacing them as unit is that the housing forms the structure that cradles the return spring. It wouldn't make sense to take it apart. It's hard to do (I fooled around with the broken one) and not worth the effort. You don't save anything. If you ever get the chance to take one apart you'd see what I mean.

When you replace the unit there is only one possible way for it to go back on, so I am certain that the jiggle valve is on top.

The bad stat failed because the rubber seal around the circumference of the 'flap' (for lack of a better word to describe the stat opening piece) fell off preventing the flap from being able to shut all the way. I've never seen a seal on a stat before. The seal failure has happened twice.

The one I happened to get this time did not have a seal and made me think that someone had discovered a problem with the seals and made one without it. At that point I thought I had solved my problem! No such luck - lol.

I thought about air pockets too, but thought I remembered reading somewhere that there are no air bleeds necesary for the 4th gens...I have the FSM and the Haynes so I'll double check that. But wouldn't you think that the air would cause a hot engine condition? (expansion into the airpockets and poor heat transfer to the coolant. I've been checking the coolant overflow to see if the system is taking in any add'l fluid due to air, but haven't noticed any noticable changes.

Any other thoughts?

 

You said the engine was running cold again. Is it really and truly cold, or are you relying on the dashboard temperature gauge? It might be inaccurate.

If the engine is truly running cold, there is only one cause... and that is a missing or defective 'stat. These parts usually last for a long time, so your need for multiple replacements is baffling.

Every seasoned technician has encountered some BOB (Bad, Out of the Box) parts... but that's not really your problem. Each 'stat works for a while but fails prematurely. Bad luck? Born under the wrong star? If I get some flash of inspiriation I'll let you know...

 

I'm relying on the dash guage.

I know that is not great technique. I guess I've always noticed (as you might have) that the temp needle is rock solid when it lands. Whether it's 100 deg or 0 deg it always seems to hit the same mark every time. So when I see it read differently or move I take notice. I have had other Nissans that weren't as consistent and didn't offer that luxury. For as long as I've owned this Max I've been impressed by that consistency and have attributed it no doubt to the engine's efficiency.

Thanks for your thoughts.

 

Thanks Mr. Martin

Me and my dad just followed your instructions and successfully replaced our broken thermostat. Works great now. We got the part from NAPA who had to order it from some irregular parts supplier (not a real napa part) and it was a little different than the stock unit. Came with the housing and everything and the thermostat on the new one was clearly not removeable while the one on the nissan part is. Was only 30 bucks though and works great! Probably would have cost at least 100 bucks at a shop. Real easy to do, just loosen up the idler pulley so that the adjusting screw moved down and out of the way. Just enough room to get at the three nuts on the housing. the lower nut was a bit of a challenge. Had to get a real shore extension for our socket as a standard 2" extension was too long and made the ratchet hit against the body. Without the extension, it was too short.

I was a little dissapointed that the 'stat went out. We just got this car in the summer and have already had to replace the thermostat and the starter. Hopefully not much else will go wrong. Shouldn't if its a nissan!!! Anyhow thanks again,

 

Air Evac - http://www.wurthwest.com/newprod.html

Best thing since sliced bread.

 

I have a little to add for this.
I live in New England, and as you all know, it's been cold up here recently (actually, I think the entire country has been cold, but I digress). I noticed that if I start the car in cold, and just let it idle, not only does it take forever to get heat, but it NEVER fully warms up! I am referencing the guage AND the fact that the heater output is fairly low. However, if I drive for about 5 minutes, the temp guage swings to the horizontal position (its favorite) and stays, and the heater output is good. So I was thinking - could the stat be bad, or is the engine so efficient, that it can't even warm itself up at idle in 10 degree weather? The needle will get to about the 8:30 position by idling. I tried revving the engine a bit (held it at 2 grand) and it moved up a bit...on a similar note, I checked the exhaust output at idle (~700rpm) - there was hardly anything coming out! My friend, who knows a good deal about car repair, felt this and said there must be an exhaust leak, but I doubt it - I think the fact that it puts out such small amounts of exhaust at idle jives with the non-warming up. It's just that efficient...or am I totally wrong here?

People who live in similar weather, feel free to try idling your max and note if it EVER gets to prime operating temp without driving.
Thanks.

 

Thanks for sharing your success story. That's one of the great things about this forum, how we exchange information and learn from each other.

I got started with automotive repair by my dad, too. It can be a great father/son shared interest.

I like the short extension bars for the 3/8" drive socket wrenches. Craftsman #43537, S-K #45159, or equivalent. It's a good idea to have two or three. They come in handy.

Keep on doing your own "wrenching". As you gain experience you will also gain confidence. Add to your tool collection every now and then. Good tools are a good investment.

 

Just FYI, you might want to consider calling the dealer on some of your future parts. I know this is a little late but NAPA also wanted around $30 for it but was very surprised that the dealer only charged me around $13 for it(housing and all). Just thought you,d like to know.

 

Holy thread bump, does this also cause for the gauge to read that the engine is overheating?

 

A thermostat that is stuck shut/broken can cause an engine to overheat by severely limiting the flow of coolant.

I would remove the thermostat and test it by boiling a pot of water and submerging the thermostat in the boiling water to see if it opens (if it's not visibly damaged upon removal), if it doesn't open in a minute or so of sitting in the boiling water then it needs to be replaced.

NOTE: If you're going to use this method be sure to have a second vehicle available to drive, or have a thermostat ready to go in.


Not much can cause the dash gauge to read that the engine is overheating, IIRC a bad sensor for the dash would simply read cold at all times. So yes.

 

did mine in 1/2 hr didnt remove anything but the lower hose

 

Thanks a lot! I have an extra thermostat to go in. I was worried if it wasn't my stat it would be my water pump, but good thing that's not the case.

 

I did mine a few months ago ICW a radiator replacement; it was very easy. IIRC, it will also help access to one of the thermostat bolts to unbolt and move the horn on the passenger side out of the way.

 

Noted, thanks

 

Alright so I replaced my thermostat but I did not bother to drain the fluid so some fluid spilled a bit over the place onto the timing belt and alternator but I thought it was fine. To access oone of the bolts I had to unscrew the timing belt adjustment bolt then retighten it. I started it up then something started smoking from the car and i guess the timing belt started screeching.

I guess I am retarted that I didn't drain it and that i messed with the bolt. Am I correct? God I feel so freaking stupid. Need reply ASAP

 

Nevermind, car's running fine. I'm a boss

 

Just for future reference (and clarification):
Our cars don't have a timing belt. We have an accessory belt and power steering belt. The timing system on our cars is a series of chains.
You got the accessory belt wet, which will cause it to squeal/screech like mad until it dries off.
You should've drained the radiator, but that doesn't make you stupid, it just means you were rushing yourself and skipping steps (it's a learning experience, we all forget steps from time to time, part of being human).

But given it's good now, good job.

 

Wow really? I thought I knew so much about the max hahaha

Yeah I'm pretty happy I fixed it myself, one of the bolts was a pita to get out though and it was frustrating