With a/c off, I start the car and the fans come on. And they are loud. Is it possible that the thermostat is stuck? Or is there some other issue I should check first?

 

Any SES lights on?

 

No SES lights and no trouble codes. It just seems that the fans shouldn't come on (both of them) with a cold start. I was hoping that this is a common issue with a relatively simple fix.

 

You might try resetting your PCM?

 

If the wire that goes to the sensor on the right side head(between 6&8) has come off and,or is shorting out, this will cause this condition to happen.

 

There is no sensor in the right side head between 6&8 on a LT1.

The sensor for the PCM is located in the water pump.

The sensor for the dash gauge is in the left side cylinder head.

 

And a "stuck" thermostat would not cause the fans to run, there is no way for the PCM to know the t'stat is stuck, except by inference when the coolant overheats.

The most common problem is a blown fuse in the AIR pump, which causes the fans to run all the time, but that would set a code and turn on the sES light. Get it scanned.... there may be some other code present, your SES light may be burned out, there could be a short across the ALDL connector pins, fan relays may be screwed up, the coolant temp sensor may be indicating an incorrect high temperature........

 

Opps,sorry wasn't paying attention. Try unplugging the coolant sensor and see if it stop, then you would know where to start looking.