Engine Cooling Issue

fheckro · 12-19-2009, 09:36 AM

Ok here’s the deal.

I’ve got a 67 GTO with a 455. I’m running a Milodon water pump, March serpentine belt setup, Be Cool radiator, the engine is set up for the street with a Comp Cams 51-224-4 , Edelbrock aluminum intake and Hooker super comp headers.

Here’s the problem

No mater what I do it will not run below 220/230 degrees under any circumstances in the summer when using electric fan/fans/shrouds/ect. It won’t idle at 180 in winter. I’ve tried using the Griffin radiator, dual fans pulling or pushing, single 2000 cfm fan with or with out shroud. I’ve added Water Wetter and even tried an air dam under the radiator support and removing the thermostat.

Never any difference!

Finally :

I switched back to the factory belt driven fan and shroud. Ta daaa! The engine now heats up promptly to 180 and stays right there. Only thing is…now I sound like a flipping
C-130 taking off every time I wind out 1st gear. Is there no justice? I don’t remember the factory stock Pontiacs sounding like that.

What gives?

66tempestGT · 12-19-2009, 10:20 AM

is the factory fan a clutch fan? is the clutch locked up? some serpentine belt systems use a reverse rotation water pump. are you sure you have the correct pump.

geeteeohguy · 12-19-2009, 10:50 AM

I'm using the GM flex fan off of a '69 Caddy on my '67...it pulls a ton of air and is quiet. As per above, check for a locked up fan clutch. That would be my guess, too.

Rukee · 12-19-2009, 11:01 AM

I suspect it has no clutch fan and the fan blades are bolted right to the pump.

1970 Lemans · 12-19-2009, 11:56 AM

If you are using a fan clutch, I would offer the following:

A number of years back, the fan clutch on my 70 pontiac was replaced (old one was leaking). Following replacement my car also became very loud (sounded like a 747) in first gear (less noticeable at higher speeds). Turns out that the new clutch was of the heavy duty variety. When the standard duty clutch was installed, everything (including cooling) was fine.

fheckro · 12-19-2009, 06:54 PM

Thanks

I am indeed using a brand new stock clutch with factory original fan and shroud. The March serpentine belt system (which I do not recommend for other reasons) turns in the stock direction. It could be a heavy duty clutch though; I will have to check that. Actually, I think I will just order one from Ames like I should have the first time.

66tempestGT · 12-19-2009, 08:33 PM

if your engine really is trying to be too hot all of the time the clutch may be working properly. it might really be struggling to keep everything cool.

1970 Lemans · 12-19-2009, 09:42 PM

If you live close to a NAPA store, you can also pick up a regular duty fan clutch from them. I believe the PN you would be looking for is TEM 271308 ($37.99) ... but you can double check that via their online site.

fheckro · 12-20-2009, 08:26 AM

Thanks for the tip. I will try NAPA

I got the other one (against my better judgment) from Advance.

fheckro · 01-09-2010, 12:48 PM

Finally replaced fan clutch. Noise greatly diminished! Thanks again!