Coolant Temp Isuue

[Codester]

Ok I've done a few searches but all of them never helped me out. I bought the car and it just started not heating to the proper temp. The coolant basically stays around the 130-150 area. And when I drive and idle it stays there so I thought it was the ECT sensor. But I left it running to see if it was the ECT and right around 210 the fans kicked on. The gauge and PCM were spot on. But when I start accelerating again it falls back down. I'm thinking its the thermostat but I thought a colder thermostat just takes longer for the car to warm up but it stays at the 130-150 range all the time.

Any ideas?

[BillBoost37]

Sounds like your thermostat failed. Some of the better stats fail in the open postion. Meaning that your car will have trouble heating up, as you describe. This is preferred to it failing closed, which causes you to overheat.

Swap out your thermostat and you should be all set.

[Codester]

Thanks Boost. I've always had mine fail closed in all of my past cars. I've always had 4G63 DSMs so this V6 N/A is new to me.

[Codester]

Boost: Replaced the thermostat, and bled the system of air and now it goes a couple of ticks above the middle line between 100-210. Then the temp drops back to the middle line again but the fans are not turning on. I'm stumped. I had it idling for about 30 mins last night and it never went above the 2nd tick after the middle line. fans never kicked on either. Checked the part number and it is correct. It is a duralast OE temp thermostat. Any ideas?

[SnowFlake]

Maybe the coolant just isn't getting hot enough to warrant the fans coming on. Could it just be that everything is fine? lol

[Codester]

could be... I come from owning 3 different Turbo Eclipses so I'm very paranoid with any car now haha. I put a good load on the engine and wouldn't go above the 170ish area. It could be fine but then again my temp sensor might be acting up too. Car has 170k on it.

[SnowFlake]

What t-stat did you get? If you got a 160 I'd go with a 180 (for other reasons)... if you have a 180 then I'd assume everything is fine.

[Codester]

Its a oe temp t-stat from duralast autozone brand. So i should see 195 before its fully open. I just jumped on the highway for 30 minutes and still the same thing. I think the thermostat is bad even though its new.

[BillBoost37]

Really depends on your outdoor temps and efficiency of the radiator etc. If you are seing about the half mark, that's in the area of correct.

The fans are programmed to turn on at 216F and 228F in most of the files I've looked at. Which is rippin high in my eyes. However GM did it for efficiency.

[Codester]

I'm all happy that it doesn't overheat. But from what I've learned from the turbo Eclipse ECUs when tuning them is closed loop didn't start until about 180 degrees. Until then the ECU is ignoring the o2 sensor and going by the hard coded values in the fuel tables which sucks for gas mileage. Is it the same with these PCMs?

[Codester]

Update: Replaced a thermostat with a Napa Premium made by Stant and put it in a pot of boiling water and it opened up between 190-200 so its fine. Installed it and it does the same thing. The only other reason is somehow the coolant sensor screwed up while installing the newer thermostat.

[chevy468]

My car is doing the same thing. Did you ever figure this out?