2001 GPGT Low Coolant Light

Hey all. Thank you for your previous help. My GP was stumbling something fierce under acceleration, turned out to be a faulty coolant temp sensor. I replaced it, and the T-Stat (165 degree is all autozone had at the time), and did a coolant flush and it seemed to be fine. EXCEPT - now the low coolant light comes on until the car reaches temp, and it overheats in Boston traffic. I bled it and thought it looked fine, and even now there is plenty of fluid in the resevoir and in the radiator. I have tried to bleed it again and it just streams out clean fluid. Any ideas?

Thanks! I just bought a damned house, and if I can't keep this thing running, I'll be carless (or homeless :-( ).

the coolant level sensor is in the passenger side radiator tank about a third of the way down. It looks like a small box about 1-1/2" square. It is possible that it is gummed up with sludge causing the light to come on. Since the car is getting hot (210-230 idling in traffic is normal by the way), it's possible that you still have air in the system, or you have an intake gasket leaking causing the car to lose coolant through the intake. Does your car steam excessively, or have a sweet smell to the exhaust?

As long as you are sure coolant is not being consumed replace the coolant level sensor located on the right side of the radiator located 3" below the filler neck.

Pic is worth a thousand words. :biggrin:

http://i5.photobucket.com/albums/y186/lizzywiz/coolantsensor.jpg

I get that the coolant level sensor *may* be defective causing the light to come on, but that doesn't explain the overheating/running hot or the light turning off at temp. I guess richtazz may have something...gotta be air in there -expanding at higher temp and telling the coolant level sensor everything is ok. Maybe I didn't bleed it right, or enough? Can someone give me an idea about what I may be doing wrong? I turn the car on, idle it for 10-15 mins, then turn the bleeder screw on the top of the t-stat housing about 1/4 turn and wait until steady coolant comes out. Then tighten it all back up and go back to the xbox :-). Sound right? Any tips or other ideas? I'm not the best tech in the world so I'll take all the advice I can get.


Forgot to mention, it doesn't steam, and actually it smells like it is running a little rich but that has been the case for the last year or so now.

Someday I need to replace the front struts too...should I bring it to a shop for that?

I get that the coolant level sensor *may* be defective causing the light to come on, but that doesn't explain the overheating/running hot or the light turning off at temp. I guess richtazz may have something...gotta be air in there -expanding at higher temp and telling the coolant level sensor everything is ok. Maybe I didn't bleed it right, or enough? Can someone give me an idea about what I may be doing wrong? I turn the car on, idle it for 10-15 mins, then turn the bleeder screw on the top of the t-stat housing about 1/4 turn and wait until steady coolant comes out. Then tighten it all back up and go back to the xbox :-). Sound right? Any tips or other ideas? I'm not the best tech in the world so I'll take all the advice I can get.

Forgot to mention, it doesn't steam, and actually it smells like it is running a little rich but that has been the case for the last year or so now.


When you bleed make sure the engine is warmed up enough for the thermostat to open, then bleed. Sometimes it is better to elevate the front end of the car a little. Technically, the radiator should be higher than the engine. Other than that it is a no brainer. If no air comes out then you have another problem with the cooling system. Thermostat or maybe it needs a cooling sytem flush, etc.

Unless you are mysteriously losing coolant or have driveability problems other than running a little higher on engine temperature I'd be reluctant to point a finger at the UIM/LIM gaskets at this point in time.

Thanks bnaylor. I will bleed it again tomorrow sometime. It runs great actually - except for the overheating. I rented a car over the weekend and boy did I miss the balls of my little 3800. If I gun it from a light after sitting in traffic, even if I get it to highway speeds, it will still hit over 200 deg. Eventually it comes back down, but I am hesitant to do much city driving with it this way. Is it possible to trap air in the coolant system that won't bleed out? At the moment, she doesn't seem to draw any coolant out of the reservoir at all so I don't think I'm losing or burning any.

I doubt it is the intake plenum at this point, but I will look at that too.

Thanks bnaylor. I will bleed it again tomorrow sometime. It runs great actually - except for the overheating. I rented a car over the weekend and boy did I miss the balls of my little 3800. If I gun it from a light after sitting in traffic, even if I get it to highway speeds, it will still hit over 200 deg. Eventually it comes back down, but I am hesitant to do much city driving with it this way. Is it possible to trap air in the coolant system that won't bleed out? At the moment, she doesn't seem to draw any coolant out of the reservoir at all so I don't think I'm losing or burning any.

I doubt it is the intake plenum at this point, but I will look at that too.

Sounds like you're on the right track. If it runs good and there is no actual coolant loss I'd treat it as a typical cooling system problem.

Since you had an ECT - engine coolant temperature sensor problem earlier I'd check out the thermostat to make sure it is working correctly. Those type problems seem to go together or hand in hand. The other thing is the Dexcool gets flaky after about 5 years of life so you might consider a cooling system flush. And maybe canning the Dexcool for another coolant such as Prestone Extened Life which is fully Dexcool compatible and based on the same organic acid technology (OAT).

The problems you are having are common for this time of year. I lost track on how many we helped last year.

Also, check to make sure your cooling fans turn on. Good luck!

If it's only creeping up around 210 and then cooling down, this is normal. The factory switch is calibrated to turn the fans on around 215-230 degrees. Like Bob suggested, check fan operation as the temp creeps up. If the fans are coming on, then you're fine. The 165 t-stat is too cool for a non-modded car. I would replace it with a factory 195.

Also it depends on where you live as to whether you can get by on a 160 degree thermostat. Where I live no problem even without mods. Up North different story. You could probably get by with a 180.

Also it depends on where you live as to whether you can get by on a 160 degree thermostat. Where I live no problem even without mods. Up North different story. You could probably get by with a 180.
I put a new one in mine and didn't notice until I got home with it that they had given me a 195. I can tell it does run a bit warmer which is what I did not want to do. My temps go up quickly once I get off the road. I'm thinking my radiator may be needing replacement or a good cleaning.

I put a new one in mine and didn't notice until I got home with it that they had given me a 195. I can tell it does run a bit warmer which is what I did not want to do. My temps go up quickly once I get off the road. I'm thinking my radiator may be needing replacement or a good cleaning.

Thats a good idea. The radiator is made of of several lines that pass coolant from one side to the other. They do get clogged. The radiator can be flushed and cleaned separately. You'll probably find that it will make a difference since most our overheating or higher temperatures are at idle or low speeds even though the fans may be operating correctly.

The 195 is there solely for emissions control.

I'm sorry I mis-spoke - my t-stat is a 180/185 not a 165. It was the next cooler than stock. I noticed today too - my car hit about 205 and the fans did NOT come on. I'm baffled, sorry to be a newb, but I'm not sure what to check next.

I'm sorry I mis-spoke - my t-stat is a 180/185 not a 165. It was the next cooler than stock. I noticed today too - my car hit about 205 and the fans did NOT come on. I'm baffled, sorry to be a newb, but I'm not sure what to check next.

To quickly test your fans, make sure engine is fully warmed up, turn AC on MAX and blower on high. Then check both cooling fans. They should both be turning on at least low speed.

I think you're fine with the 180 thermostat.

Rich pointed out earlier that under normal conditions the fans will not turn on until the temp. gets higher at 215 degrees on up. It varies.

A 180 stat is fine as Bnaylor stated. It sounds to me that you're worrying yourself unnecessarily. If your temp never approaches 240, there is nothing wrong. If you noticed the change in temp guage reading after changing the CTS, that's normal too. Maybe someone else will agree or disagree with me, and if so, please chime in, as I don't want to mislead you.

Thanks for everything so far.
bnaylor/richtazz
You guys have an Amazon wishlist or anything? After all the advice I have seen you give here, you deserve something. :-)

I'll take a Snap-on mtg2500 scan tool with 06 updated cartridges for trans, abs and troubleshooter insight, :cwm27: . Thanks for the appreciation, it's nice to hear.

A 180 stat is fine as Bnaylor stated. It sounds to me that you're worrying yourself unnecessarily. If your temp never approaches 240, there is nothing wrong. If you noticed the change in temp guage reading after changing the CTS, that's normal too. Maybe someone else will agree or disagree with me, and if so, please chime in, as I don't want to mislead you.

As long as it doesn't go too far above that I agree he should be OK. Personally, I'd be uncomfortable with anything over 200 at this time of year but I'm in the desert Southwest and we've gotten well over 90 degrees already but thats my circumstances. I'd keep an eye on it and see what happens when the really hot weather kicks in.

Rich is correct when the ECT (CTS) is changed the internal resistance values will never be the same as the original one so there may be some deviation on the temperature gauge. The problem is the gauge cannot be calibrated by a layman.

Speaking of a Snappy MT2500 scanner and other good ones they have the capability of reading out the ECT temperature right off of the PCM module which is more accurate than the gauge.