Pinto Car Club of America

My 1975 2.3L pinto engine is fluctuating temp from about 200 all the way up to 230.  Even at a constat load, it will rise to 230, then drop to 200 over and over again.  It has always run hot but just recently stared fluctuating like that.  I read on another post that the same thing happened to someone else that had a clog somewhere in the system.  I recently put in some radiator leak stop, probably too much of it, to plug a small hole in the radiator.  It stopped the leak but i have a feeling that i plugged something else up as well.  Any tips of getting everything flowing smoothly?

 Possibly Bad News..
Before you make matters worse, Drain and flush the entire cooling system. Refill with water (distilled) with the heater set to the on postion and start engine. if you begin to overheat, stop . Then allow to cool,drain& flush out water. Replace thermostat. refill again, make sure that all air is burped out of the system at the Highest hose connection . If it still overheats, Drain and have the radiator replaced or repaired. Stop leak is a real catch -22 repair. It could cost you a blown head gasket or worse from overheating.

Hope it's just the stop leak..

Pintosopher

awhile back when it was running hot I took out the thermostat to make sure i didnt have a problem elsewhere and the engine never heated up so its not a problem with the radiator or water pump.  Ive got a feeling that there is a lot of air in the system which isnt allowing the thermostat to open correctly.  Not quite sure how to purge all the air out though.

I purged the system of air and now it runs at a constant 190  :D

Excellent.. But please, no more stop leak! :read: 8)

Glad you got it working like it should. 
I had a bad thermostat once that liked to stick.  It caused similar issues until it was replaced.