Overheating '65 442

[Guest]

Hi all. This post is for a computerless friend of mine with a 65 442(I have a 63 Pontiac Grand Prix, Pontiacs never overheat 65 Olds 442 with a 040 over 455, Edelbrock heads, mild cam, headers, 4 core alum radiator. The car ran hot before the rebuild and since is even worse. At idle on a hot day it will climb to 250 and higher, after it gets hot it doesn't cool down. Timing, water pump, fan, radiator, all the usual suspects have been checked. Would certainly appreciate any thoughts.

Mike

[rocketraider]

You're sure the temp gage is accurate?

Is the engine showing physical signs of overheating? Smoking gaskets, boiling coolant etc.?

How about your pressure cap and thermostat? Make sure you have the proper type, not mixing an overflow-jug type cap with an open overflow or viceversa. Also antifreeze concentration.

If the (I assume) clutch fan is working, do you have a fan shroud? Try baffling the radiator to direct all possible airflow thru the core. That means sealing the bumper to the core support, covering all openings between the radiator itself and the support, and using a fan shroud.

What weight oil? How about fuel mixture? Excessively lean carburetion will make it run hot. Check your available gasoline; that oxygenated garbage will unsuspectingly lean the carb. Check the exhaust temps at the top of the header.

An overbored 455 is going to run a little hot, but it should cool down when stopped.

BTW- my own experience with Pontiacs says any engine larger than a 389 will overheat willfully! <img src="http://www.aaca.org/ubbthreads/images/graemlins/wink.gif" alt="" /> A buddy with a stableful of them will tell you the same thing.

[Guest]

Hello Mike,

Are you an OCA member? There has been some super great info on this topic in the past 6 months or so in the club newsletter, JWO. If you aren't in OCA, you should join! If not, try to get someone to get you the information out of past newsletters. I could copy it and fax it to you if you like.

Richard Cornell