fan stays on after cutting off engine - coolant sensor prob?

mrobins3 · 09-09-2003, 12:30 AM

A few days ago after some normal / light driving, I turned off my engine and the fan stayed on for several minutes. I let the car cool down then a friend took it for a spin and it did the same thing after he turned it off.

We let it sit a few days then I took it to a garage (not a Saturn dealer, but my regular mechanic) where they told me (a) they couldn't diagnose it because although a GM dealer they were not a Saturn dealer, and (b) they thought it might be a CRACKED ENGINE COOLANT TEMPERATURE SENSOR. I discovered later they just pulled this off the GM service website and didn't actually run a diagnostic on my car.

My question is whether this seems accurate. I note that there was no steam, gurgling, radiator overflowing, etc. JUST THE FAN BLOWING THOSE TWO TIMES WE DROVE IT.

Can anyone offer any advice - I already paid these people to tell me this vague information and realize I probably need to take it to the Saturn dealer but just thought I'd arm myself with the best information.
thanks in advance if anyone can help . . .
Margaret R

sc2_ct · 09-09-2003, 01:26 AM

You can test the ECT sensor by putting it in boiling water and measuring it with an ohm meter. Since the water will be about 212-F, you should see in the range of 200ohms. Now meausre it in ice water. It should measure closer to 100,000 ohms. If it doesn't behave like this, it needs to be replaced.

Also, while the water is boiling, toss in your thermostat to make sure that it opens up when heated.