Thread: Engine Temp Problem....Cant figure it out

Hey guys! New to the forum and thanks for taking the time to read and maybe help with my problem.

I have a 2004 Grand Prix GT2, with 250k highway miles. It had been sitting for a little over a year before I decided to take it out of the garage and start driving it again.

Issues that I had with the initial test drive last week, no hot air blowing from the heat vents when heat was on, and engine was at the 1/2 mark with it just on in the driveway, and it would fluctuate between 1/2 and almost to the red, but never in the danger zone. (from what I remember 1/4 -1/2 fluctuating was normal)

I took it to the local mechanic who told me I needed a new water-pump and radiator.

I figured to try to do a few things myself, I drained the system, flushed it and the heater core. I did see some nasty rusty stuff that came out the heater core but eventually got nothing but clear hose water. This did not fix the problem. I went out and purchased a Duralast water-pump from auto zone and installed it myself.

What happens now is that the engine will operate between the lowest line on the temp gauge to barley 1/4 when driving, and I get Luke warm to normal heat when driving.

System was bled, but not a new T-Stat was installed, it was new right before I put it in the garage.

This is what I am thinking, and I hope this is where someone who knows more can help me. When I first took it out, the water-pump was bad and T-Stat was stuck open with a blocked heater core. Some water was moving through the system that allowed the engine not to overheat completely and the heater core was clogged that caused no heat. Now that the water pump is fine, the T-Stat could still be stuck open, with normal water moving though the system but not warming engine to normal operating temp due to the T-Stat.

I am puzzled and need help!!

Thank Guys

Even though the T-stat has low miles, it's probably gunked up and stuck open. Low engine temp is a pretty common sign of it being stuck open.

You can pop it out pretty easily and look at it. Put it in a pot of boiling water to see that it works right.

Will do thanks!

Originally Posted by Buggsy

Even though the T-stat has low miles, it's probably gunked up and stuck open. Low engine temp is a pretty common sign of it being stuck open.

You can pop it out pretty easily and look at it. Put it in a pot of boiling water to see that it works right.

For anyone who might be looking at this threat, The T-Stat fixed the problem!!

Tell me about it, I was close to doing the radiator! Thank god I didn't do it. The water pump was failing though, bearing was very loose...