1991 Camaro z28 305 TPI stock. A few weeks ago I had the local chevrolet dealer service the transmission and fix a wiring issue with the front drivers side turn signal not working. It was a wireing issue.
Anyway, the day I brought it home I noticed one of the front fans kicking on after I drove the vehicle. I first noticed it after driving for awhile, and then after I would turn the car off and turn the ignition into the start position before turning it over. It seems to happen occasionally, but not all of the time. I had never noticed this before.
Tonight I was driving the vehicle for maybe 1/2 hour, got home, heard the fan kick in and just prior to shutting the vehicle off and noticed the coolant fluid boiling in the resovoir container. I turned the key over to the start position and the fan started blowing and the boiling quickly stopped. I had the radiator and coolant fluid flushed last year. The termperature gauge always reads around 220. Any thoughts. Is there anything the dealership mechanics could have done to cause this? I have read a few posts w/particular problems, wondering if you have any thoughts regarding my specific issue. Thanks for any info!

 

I would start with a new radiator cap.(16lbs vented ) Sounds simple but a bad cap can cause problems.