I have had some problems with the cooling system of my 85 trans am lg4. Started after having the cam changed to a mild crane powermax no 114112 i think it was. the pressure in the system got way too high and hoses startet popping of, also there was a leak in the plastic part of the rad where water sprayed like crazy. Also the temp climbed, but i dont think coolant boiled, im not sure...
Changed the tstat and the rad cap. Noticed that there was alot of air in the system when i changed the tstat. Filled it up and drove the car maybe 2 miles. Now the pressure was ok. Radiator still leaked of course but it was pouring a little, not at all like before.
Everything seamed fine til I stopped an let the car run at idle. The temp climbed to about 230F. Then it fell rapidly to about 180-190F or so, and thats what puzzles me. Never seen temp fall so fast!!
What can have caused this? Can air still trapped in the system do this?
My main fear of course is a blown head gasket.....
By the way, I have one mechanical fan only, so it was not an electrical fan kicking in..

Hasse

 

I would check the clutch in your fan and theres a possibility you have a air bubble in your cooling system.

 

Thanks!
I dont knoww how this clutch works....
Yeah an air bubble souns like a possibility since I changed the tstat and besides, there is a leak in the radiator.