slow heating

[COPO 70 RS/Z28]

OK, Maybe someone has an idea,



Im pretty sure this is the factory set up. radiator recored, water pump ok, thermostat replaced, stock timing setting, clean coolant.

Problem: Sitting at idle the car will slowly heat, and continue to heat up very slowly, if I drive it will cool back down,

The assembly manual shows the setup as you see, assuming it is stock, any ideas?? It is now running a 180 standard themostat, oem appears to be 195. Assuming factory stock the system even though build without a shroud should run at the thermostate temp?? shouldn't it

[Charley Lillard]

No fan shroud ?

[Plowman]

You could try drilling a 1/8" hole in the thermostate. This will let the air out of the cooling system that gets traped. Paul

[Salvatore]

Try a 160 stat in it. I never run anything over a 160 in these cars.

[VintageMusclecar]

Operating temps of 195° and above were fine back in the day when we had decent gasoline, but these older carbureted cars simply do not seem to like to run right at those temps with today's gasoline. I can't begin to count how many complaints I've heard about running hot and constant heat soak/vapor lock problems on these older cars.

Also consider that the gas today is formulated for EFI (--there hasn't been a domestic carbureted vehicle available since ~1985). The ~10% ethanol in today's gas typically causes older carbureted cars to run a little lean, esp. at idle/low speeds, which can cause engine temps to rise.

I would first try adding a better fan and installing a shroud as suggested above. This alone may resolve the issue, but if not, you could try richening up the idle on the carb just a bit and perhaps try bumping the timing a little as well, that may help alleviate the creeping temps.

I'm also a big advocate of 160°-180° `stats in these older cars as well.

[MosportGreen66]

160 deg Milodon Thermostat! Best out there...
How old is that radiator core? Looks like it has miles on it.

[scuncio]

The 160 degree stat is a good idea but I bet the lack of shroud is 'the' problem. What shroud design were BB Novas supposed to come with?

[COPO PETE]

Shroud is a definite. Try a 1 inch bigger crank pulley, or a 1 inch smaller water pump pulley. On my 68 Impala I have put on a electric fan on the front(pusher) for if I'm in parades.
Peter

[69SSZL1]

Also you can try "Water Wetter" that stuffs really helps.
http://www.summitracing.com/parts/RED-80204/

[Fast67VelleN2O]

The fact that your fan is so small and you have no shroud is the problem. If you go with the shroud at the very minimum I think you will have it mostly under control.