unusual heat problem

[martian369]

check engine like is on. went to auto zone and did the diagnostics check, said low coolant temp. I let the car ( I think) warm up. I hop in and turn the heat on and its slightly warm even after a 15 min drive with a 5 min warm up. my indication in the dash says maybe a tiny bit more than 160 the lowest number on the dial. and it never gets any higher. im thinkin maybe my thermostat is stuck open but I lift the hood and my engine is hot. am I missing something? I’d like to find a picture or drawing of this system but im tired of looking. any help would be appreciated!

[richtazz]

Sounds like a stuck open thermostat to me also. If you have a 3800 engine, it's easy to change too. The 3.1 is not so easy, as the housing is tucked under the throttle body and the back bolt is very difficult to access.

[martian369]

i sure hope that it fixes it and i know its easy to get too. i was surfing through the forums and i seen something about two acuators that operate i guess airflow to defrost and vents and one that does mixture. any of those you think pose a problem? there was a recall on my car a few years back for the intake manifold leaking fluid in to the intake haven't got it done yet, monitered fluid levels seem to stay the same don't suspect its failed, though i may be wrong...

[richtazz]

No, the actuators under the dash wouldn't trip the low temp code. All they would do is cause low heater output. Your problem definitely sounds like a t-stat stuck open. If your car is unmodified, and you live in a cold winter state, stick with the stock 195 t-stat. If you're modified, or live in a more temperate weather state, a 180 t-stat will serve you best.

[martian369]

hey i'll give it a shot. i work overnight maintenance so i'll change it tonight and get back to this tomorrow morning. im so glad its like a 20 dollar part. hope we talk about it later.... oh any thing i need to know before removing it? extra rags or something else?? never mind that haven't changed it yet my car "under the hood" is all stock except the intake.

[martian369]

umm found both fans running this morning when i started it up just to get it warm to change the t-stat. disconneted the fans and drove home from work. it reached an astonishing 175 degrees. so thats a new problem. where's the temp. switch for that fan? grabbed the radiator hose while the car was running felt like air burping through the line. which tells me my t-stat must be open cause in "i guess" normaly cold engines the t-stat should be closed. allowing the engine to heat up quicker. found radiator fluid to be low also which means i need to have my recall done asap. I ain't leakin anything but oil from my oil pan gasket. which i've looked into and i need to lift the engine to reach all the bolts... ain't gonna happen right now! if you don't know, i got a grand prix gt 3.8L v-6. any comments??????????

[BNaylor]

On the SII 3800 engine the ECT sensor is what the PCM module uses to reference engine temperature and control the cooling fans. Located below the thermostat housing on the lower intake manifold.

Until engine temperature reaches 220 - 230 degrees F the fans should not be operating unless the A/C is on. Both fans should turn on in the low speed position when temps reach 220 - 230. Above 230 high speed.

If the fans are turning on at start up without the A/C on then you may have a flaky ECT sensor or bad wiring between the ECT to the PCM module.

If you have air in the cooling system then it should be bled out. The relief valve is located on the thermostat housing.

Unexplained coolant loss could be a UIM or LIM problem.