cooling/temp question

Discussion in 'The Bench' started by jaystoy, Jul 21, 2018.

  1. jaystoy

    jaystoy Well-Known Member

    So, in the spring, I had a slight mishap with the 455 in my 71. Was going up a hill, I floored it, downshifted and the tires just let loose. Probably tached to 6k!!Pretty cool. However, the alternator/waterpump belt jumped and the car overheated pretty bad. Luckly I had a spare belt in the trunk with a jug of water and jug of coolant. Since then, the coolant system has just not been the same. The engine use to stay pegged @ 180 degrees. Now, as I drive, it is constantly fluctuating. The temp goes from 170 degrees to 185-190 degrees, back and forth, back and forth. I swapped the thermostat with a brand new one. Did my best to burp the motor. But the temp continues to fluctuate. I also rented the coolant pressure tester, no leaks and it held the pressure. Put on a new 16lb cap just in case. And tonight, I used the combustion leak blue dye tester also to see if maybe I blue head gasket. It stayed nice and blue. So why does the temp fluctuate? Never use to. Still trapped air somewhere? Water pump issue?
     
  2. OZGS455

    OZGS455 Oh what a wonderful day!

    Dunno..but mine fluctuates too
     
  3. yachtsmanbill

    yachtsmanbill Well-Known Member

    Electric or mechanical gage? My electric gage fluc's around town with the AC on. Open roads its 160F all day long, Around town up to 220 (75F ambient) and wiggle the sending unit wire it all settles down. Give the upper hose a good squeeze for a real world temp reading. Remember mom feeling your forehead? "You have a fever..." or "Youre OK; now get dressed for school...". ws
     
  4. BuickV8Mike

    BuickV8Mike SD Buick Fan

    My car's cooling profile is different now that it has overheated as well. Not really sure why but it is different in a few ways. Engine also doesn't feel as "tight" as before. Thinking it has to do with some alum components that have increased clearance now, as alum grows so much more than cast iron with temperature increases but thats just a guess.
     
  5. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    It is the thermostat. A certain amount of movement is normal during warm up, but it should stabilize and not move much after that. Unless you drove around for awhile not noticing it was overheated, you didn’t hurt anything. Try another stat.
     

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