[johnpro]

I don't get it. Kkettel can run his engine with a 2365 cfm electric fan. My 2300 electric fan was a complete bust, even with a Griffin aluminum radiator.

I tossed the electric fan and went back to a mechanical flex fan. This helped, but still not enough. It started running so hot in Reno on the VMF cruise that I had to leave the group and take her for run up the mountain to cool it down (anti-freeze started blowing past my radiator cap).

When I got back to Sacramento, I tossed my March underdrive pullies for stock sized chrome ones (stole them off my son's car since he has no reverse right now away *LOL*). This helped a little more, but it's still not enough.

So currently I have a Griffin aluminum radiator, flex fan, stock pullies and water pump, stainless steel hoses, and stainless steel catch can. The radiator has about 3k miles on it, the engine and water pump now have 6.5k miles on them. The thermostat was replaced when I tossed the electric fan about 3 weeks ago.

If I'm moving, or the outside temps are below 95 degrees, the car runs very cool. BUT if I get stopped in traffic and the temp is over 95 (half the year in Sacramento), look out ... the temp gauge just keeps rising until I get moving again.

I don't have this problem in my son's '65 or daughter's '69. What am I missing here? It's a real pain to get stuck in traffic right now comming home from work.

 

[L20068]

Do you notice any odd vibrations/RPM changes when you're sitting still as opposed to driving?

I was having the SAME problem you were and the problem was timing/vacuum related - When I'd be sitting still, read no advance, the engine would heat up and my tach would slowly rise a couple hundred RPM.. as soon as I started moving again, the temp would cool down.

I solved it by replacing the timing chain and vacuum advance on my distributor.

 

[2bav8]

What thermostat are you using? I've found 180 to work best in my car.
I personally don't care for flex fans, but I don't know that I would blame that.

I used to over heat in the AZ summers too. A nice hi-efficiency 3-core radiator from NPD solved that, along with a clutch fan. Your radiator "should" be far superior to mine, so I don’t know what to think. Anyway you can try a clutch fan setup temporarily?
Also, are you using a decent fan shroud? I don't remember seeing one at the Knotts show, but I think you were electric then.

 

[whisperer]

John, there's only a couple of things that are changing between the conditions where you overheat and when it doesn't. The car speed and the engine speed. The car speed will give you enough air flow through the radiator and the engine speed circulates the coolant faster through the system. The problem has to be one or the other because you are actualy creating more heat with the engine when the car is moving, and you don't have the problem then.

The one thing I noticed at the Reno run was that the fan shroud was not actualy working like one. The big gap in that particular shroud at the top is a great place for air to draw from and through the fan instead of drawing that air through the radiator. Did you replace that shroud yet? If not you can certainly check it by temporarily blocking those gaps and see what the result is. Maybe duct tape just to check?......... *G*. Even that bitchin Griffin radiator has to have the entire flow from the fan going through it.

You are overheating when the car is stopped at an idle. What happens if you step down a little on the gas and just let it sit parked at about 3000 RPM's? Will it stay cool then or does it still overheat?

 

[Guest]

What about the Radiator Shoud ??

 

[Huskinhano]

L20068 is on the right track. What's your state of tune? You could be on the lean side and/or lazy timing. I seem to remember you saying you have your distributer connected to the ported vacuum port on your Edelbrock. With late ignition timing, you'll run hot. And with without full vacuum advance at an idle, this may contribute. Basically what I'm saying, without full vacuum advance, you may not have enought timing to cool it at an idle. Remember, not enough timing and you'll run hot. Also fuel mixture is important.

Ported spark advance was a product of early emissions controls in the late 60's and early 70's, remember they use to run hot? Personally, I'd never run ported vacuum advance, unless you'r maintaining a completely factory setup. I think this is a good way to get yourself into trouble. As the throttle plate opens more, the more vacuum advance you have, EVEN UNDER A HEAVY LOAD WHEN YOU DON'T WANT IT! Also keep in mind some vacuum advances will have as much as 60 degrees.

At least with manifold vacuum, the timing will retard when you don't want or need it and will advance it when you do need it.

 

[Guest]

It may be a long shot John, but you may also want to check your heater core lines to assure they are not reversed. If you have the top line running to the intake then you may create an air void within the system which causes a lesser effieciency for cooling....

 

[msgjvh]

One more suggestion. How far is the fan running from the radiator? I put my new 4 core in from Sac Mustang and it brought it alot closer. I don't have any problems now. They recommended running the fan pretty close to the radiator and a good tight shroud. It may be worth a visit to them just for additional suggestions.

 

[whizco]

Hey John,

Did you get my pm from last night? Just a couple of thoughts also.

 

[kketell]

Take out the anti-freeze and put in water with Purple Ice. You don't need anti-freeze if it's not freezing out.

What kind of electric fan did you put in? I had a perma-cool unit before that flexed so much that when it was running it was almost an inch away from the radiator; not terribly effective that way.

I am also running an Edelbrock high-flow water pump. I'm running a 165-degree t-stat.

 

[mlnielsen]

Head gaskets backwards?

Faulty temp sensor/gauge?

Electric fan setup as a pusher, not a puller? Receiving full 12V?

Underdrive pullies are bad for cooling and charging at low RPMs.

Are your stainless hoses a full 1 1/2" ID? AN type fittings should be at least #24.

Timing, timing, timing. Get an MSD adjustable timing box.

Maybe you need to change your radiator bearings...hehe

 

[70_Cougar]

You have a lot of good suggestions, another one to add to the list is the torque converter. The more "loose" the converter the more heat is generated. I looked up the B&M 2400 hole shot converter and it does not have lockup feature either. Is that a 351W you have in it? John

 

[67Acapulco]

Had the same problem when i first bought my car.
Towed home once my fault.
I rpl/ w/pump (airtex) flex fan, 3 core radiator (modine) (fan shroud from npd)
now i can sit is socal traffic in summer and it does not come close to overheating. I really think the big diffrence
is the flex fan & shroud. Good luck and keep us updated.

Just got remninded also have gano filter.
but still think bigest diffrence is flex fan & shroud.

 

[blindman]

Two Words.....GANO FILTER

 

[65coupei6]

A lot of good suggestions. I will post mine even though they might have been covered above.

Check Timing
Check carb settings
Compression (Did you mill the heads)
Thermostat (try switching it could be bad ( Maybe try a 160 or 165 stat. Not the fail safe stats.)
Radiator cap (Get a 16lbs one) Even my shop manual says 13-16 lbs.)
Shroud ( Fill those gaps I did and it worked)
Flush your radiator and also your heater core! (check my inline page under tech for a how-to)
Check the heater hoses.
Use distilled water and a additive (water wetter, purple ice, whichever)

Anything else??

 

[MarkMach1]

Johnpro, I too, was running a flex fan. The operative word being "was". I had the same situation in the Mach as you do right now. Except, here in Washington, our weather doesn't get as hot as yours does. So, consequently, when the weather here did get hot, I hated to drive my car cause I could just watch the temp gauge climb until I started moving.

This is going to sound really strange, but I took off the six blade flex fan and put on a fan from a 71 Mach 1 351C motor. It has 5 blades and those blades have quite a pitch to them, and boy, does it move air. My car now has no heating up problems( I don't like to see it over 205). In traffic on I5, when we are stopped or crawling it runs about 180. Before it would be over 205 easy.

Just an idea.