Bought 03 max last year
195K miles, automatic, ran well.
Replaced leaking radiator -no problems - no overheat
Drove through summer with no problems

Winter -
Replaced leaking valve covers, OE plugs and starter.
Drove through winter with no problems

Ambient temps getting up into the 90's now in Vegas.
Notice overheat on highway with AC on (Went over 215F)
Idle temps in the high 190's to 205.
On Highway with AC on max/recirc, slide temp selector to full hot.
Temp drops quickly to 195F and stays.
Decide T-stat is stuck closed.

Replace T-stat and outlet (One piece from Oreilly)
Saved drained coolant in clean containers and add it back (it was new from radiator replacement). Jacked front of car up to try and eliminate air in system.

Now idle temps will go over 215F just sitting in driveway. If I rev engine up to 1500 RPM it will go back down to 195F

Not sure what I did wrong. Almost all of the coolant I drained went right back into the engine minus approx half a cup which I added to the reservoir.

Obviously I did something wrong or there is a bigger problem. REALLY hoping it's not the pump, but in my experience if the pump is bad, it won't work under any circumstances.

Anyone have any suggestions? I have no idea why this would happen.

-Edit -
The car burns no more oil than normal - about a quart between changes and is getting 23 MPG average

 

Might want to replace that orielly thermostat with an oem from the dealer.

 

Seriously?
I'm don't understand how replacing the thermostat would make the overheating problem worse.

Any other suggestions?

-Edit-
I checked some more this morning. The passenger side fan kicks on at 205F and the drivers side fan kicks on shortly after at 215F.
If I don't turn the heater on and rev to 1500rpm the temp will drop to 208F, and with heater on at same rpm it drops to 197F.
Turning the AC on and getting both fans running at idle only makes it heat up faster, same goes with revving up with AC on.
The heater does blow hot air.
Starting to think the temp sender is bad, but I don't have a way to check it.

 

For one, you have a problem with your radiator fans. Both fans should turn on at the same time. There is one signal wire from the ECU that energizes one relay that provides power to both fans.

By Nissan specs, without the a/c on, when the coolant temperature gets to 203ºF, the fans should turn on at low speed. At 212ºF, the fans turn on at high speed.

The fan that waits until 215ºF is bad. The low speed winding is not working, most likely the brushes are worn. The fan motor is a sealed unit, so it needs to be replaced.

But the fans are not the cause of the overheating.

Probably the thermostat is bad, it is not opening up all the way. If you search the forum about overheating, you will read post after post that says "I bought a new thermostat at autozone, o'reillys, advanced, kragen pep boys, etc and my car still overheats." The resolution? Get a thermostat from Nissan. For some unknown reason, after market thermostats don't work well in our cars.

Here in Texas in the summer, the fans in my car start up at around 200º and cool the engine down to around 185º and shut off. This is idling or driving around town. Don't know what it does on the highway.

 

Did you burp it with the rad cap off until the coolant overflows from expansion?

 

Child_uv_Korn:
I did burp the air out by inserting a small wire under the cap to hold the inner part slightly open. Some bubbles were expelled.

DennisMik:
Interesting, you are correct. Lots of posts about the same thing.
Funy though, the Oreilly part was $38.99. I called the dealer and was
astonished to find the same thing for $26.

Guess I'll head to the dealer on Monday and swap it out.

I'll also check out the fans. I thought they only ran at a single speed.

Might be a bit premature, but I will say this :
Lesson learned, stick with OEM parts. In this case not only is it a better part -It's cheaper.

Danke Schon for the replies fellas!

 

Because one was made in China the other one made in Japan!

 

There are a few things the dealer is cheaper on, but not all things. The dealer is also cheaper on gaskets and seals than the parts stores.

Bitte

 

I can't of hand remember the dealers name but it's on eBay and local to me. He's right out side of Philly. I got tstat for like. $12. His water pump was right around $110, and tensioner was very reasonable as well. All Nissan parts in Nissan boxes. I will get the name when I can.

 

some vehicles its possible to install the thermostat backwards, that can cause overheating

 

The coolant can be low and have air in the system and thermostat can have an build up or If you installed it wrong,change it if it's not been changed. The water pump can be wearing down or clogging up. Do the coolant and get the air out first than go from there thermostat also.

 

also make sure the coolant mixture is perfect 50 50 otherwise the car will overheat.

 

Well, I just got home with the dealer T-stat. Going to go install it. Will update when I am done.

 

That's not true.

 

Since nobody mentioned this, why not see if the hoses from the engine to the radiator are getting hot. Once the thermostat opens they will both be hot. If it never gets hot you have a bad thermostat, a water pump that is not working, or a restriction. Turn the A/c on and look to see if the fans kick on too.

 

So... Update time!

I installed the OEM Nissan Tstat last night, then refilled and burped the system.
That shizz works like magic!
203F -Fans come on
190F -Fans shut off
186F idling with AC on max recirc

I did a small test drive last night, but with ambient temp at sub 70F it wasn't really fair. I didn't see over 195F on highway though.

Did another test just now with ambient temp at 80F. Same thing. Nothing over 195F.

Here's something I didn't expect though -

Since I purchased the car there has been a slight ping at part to light throttle. It's gone now.
I am assuming that the ping might have been caused by the heads running hot due to low (and more recently -NO) coolant circulation.

At any rate, the car runs nice and cool now, even with the bad low speed winding on the drivers side fan, which I plan to replace next paycheck.

Many, many thanks to everyone who replied to this thread.
I hope to learn more and pay it forward.

 

Congrats on getting the problem solved. I hope you didn't pull out too much hair in the process.

Until the outside temp gets up into the 100's, one working fan will be fine. Besides, if the engine temp does get up there, the high speed side works.

 

Not too much hair lost on this one. Not much left of it anyhow,

Exactly what I was thinking.
The inop fan still works on high and it'll only have to tow the line for another week.

 

hardly, my own winter vehicles i run 70 coolant 30 water. customers vehicles at work we do 60 coolant 40 water