cooling solution

[Ron H.]

What options do I have to increase cooling on my 67 427/390 ?

I have replaced my restored Harrison rad with a desert cool retro fit. I have been told to add a fan clutch and 7 blade AC fan blade.

It heats up pretty quickly and goes right to 210. At idle, within 3-5 minutes I am up close to 240.

Its an original gauge, but temps were confirmed by infared.

Any suggestions ?

[Jack H.]

Re: cooling solution

Confirming temp via IR, is a GOOD move! Expect the car to stay on the warm side given prolonged periods of stationary idling...there, you're stressing the fan, fan clutch + air dam components surrounding the radiator & the hood.

BUT, one thing that's wise to check is the pressure integrity of the system. You can have very minor leaks at hose connections and/or rad cap that allow the cooling system to climb over its specified pressure level.

Since PV=nRT, as pressure climbs, so does temperature!

Most competent garage mechanics have a pressure tester from Stant that allow the rad cap to be removed and the tester installed in its place. The gauge on the tester will show you what's happening inside your cooling system with respect to pressure. AND, the tester has a hand pump to FORCE pressure above system normal to spot those pesky leak points...

[Tom L.]

Re: cooling solution

Also...Be sure that the shroud is intact and all seals are doing their job. If air is pulled from anywhere than through the radiator core you lose quite a bit of efficiency. Good Luck!

[Duke W.]

Re: cooling solution

Does it have ported vacuum advance? If so, switch it to full time.

The engine originally had a fan clutch, so it sounds like someone has messed with the OE configuration, which worked okay.

Has someone added a "big cam"? High overlap aftermarket cams can cause hot running.

Duke

[Michael M.]

Re: cooling solution

I can vouch for the addition of a fan clutch. My '68 427/390 had no fan clutch when I bought the car (about 25 years ago). The PO put a spacer in its place which made it a direct drive fan. I had no idea I was missing the fan clutch until about a year ago (I learned it from this TDB). I was always struggling with the car running hot, I replaced the radiator, radiator hoses, messed with different thermostats, new radiator caps, installed an overflow/recovery tank (even though I knew it didn't originally come with one), flushed the system, and added new anti-freeze. And after all of these things it still would run hot in traffic and at highway speed. The only time it ran right was on a cool day at speeds below 50 mph.

Last year I bought a new fan clutch and fan. Now all of my cooling issues have been resolved. The car can idle in 90+ degree heat and the temp doesn't go over 200 degrees and when I start driving it drops back down to normal operating temperature.

[Gary P.]

Re: cooling solution

You can also add a AC fan pulley, its smaller and will turn the water pump faster at idle.

[Mark F.]

Re: cooling solution

I would suggest you confirm thermostat operation first. Make sure it is openning fully. With the temps you have so quickly it sounds as if its not functioning correctly. Also, consider checking your inital timing. If that has moved, your temp. will be way off. I have a 427/390 does not run anwhere near that temp.