Engine Temp always Low;Fan always on

[zacho]

Hello,

This 2001 3.4l V-6 Alero has me bummed. It has 61K miles on it, and I continue to have coolant issues with it. I had the Intake Manifold gasket replaced at about 45K, a hose at 59K, and now that the warranty just ran out it is acting up again. My engine temp. gauge on the dash is always stuck on the lowest position, and the fan comes on immediately when the car is started. It is now winter in Colorado and the heat does not come on.

I had this exact problem at 59K before the warranty expired and the dealer said they replaced a hose. It worked for about 2,000 miles. Now it is back. I checked the reservoir (no sludge), checked around all hoses and gaskets (no leaks). Any ideas??

Zach

[lincoln_mark_8]

there is prob air in the system that would cause the thermostat cannot open. the fans would kick on since there would be a hot area by the sensor. I would run the vehicle and at the top of the engine on the passenger side there is a purge valve. You run the vehicle and open that with the cap off and make sure there is plenty of coolant in the overflow bottle. Your overflow bottle may be defective as well. Mine was and I had the same problems you have. Or you have a small leak somewhere else.

[zacho]

Originally Posted by lincoln_mark_8

there is prob air in the system that would cause the thermostat cannot open. the fans would kick on since there would be a hot area by the sensor. I would run the vehicle and at the top of the engine on the passenger side there is a purge valve. You run the vehicle and open that with the cap off and make sure there is plenty of coolant in the overflow bottle. Your overflow bottle may be defective as well. Mine was and I had the same problems you have. Or you have a small leak somewhere else.

What does this purge valve look like? Does it have a black cap?

There is plenty of coolant in the overflow bottle. I detect no other leaks.

I was attempting to replace the thermostat while waiting for a replay, but I was unable to get a wrench (13mm) to turn the screw. There is no room to move the wrench,

[zacho]

Actually, the heat does come on. The car is very cold and as soon as I start it the radiator fans (both) come on. Could this be the ECT (Engine Coolant Temperature Sensor)?

[zacho]

Update:
I have tried a couple things so far. I ran the car with coolant cap removed and opened the purge valve. A lot of coolant came out and it didn't seem bubbly.

I purchased another ECT sensor ($9) and plugged it in without pulling the other sensor out. Essentially, I plugged in the new sensor just hanging in the air, no change in the problem.

My cap for the coolant is a pain to get on and off, but I do get a pressure escape sound when I unscrew while it is running (I was careful).

I have a new thermostat to try next, but my heat is coming on quite nicely (contrary to my first statement).

How did you figure out your overflow container was bad? I am not leaking or losing fluid.

Thanks for the help so far.

Zach

[lincoln_mark_8]

My cap had to be replaced also it was very hard to get off and just did not feel right. I took my car to Olds for them to check I thought I had a head gasket blown. It leaked just enough coolant to displace the water with air but the bottle still looked full. Light would come on and go off.