Help explain why

[adileo]

It was pretty darn hot here Saturday. In the 90s. I had about a 40 mile drive to a car show that was raising money for cancer.

I noticed in slow traffic (40 mph or less) my temp was always between 190-195. However, when I got on highway doing 60-65, my temp went as high as 210.
I would have thought, driving at a good constent speed my temp would be lower. So my question is why?

Car has 170 stats. Good/fresh antifreeze. I also have closed off the gap under car between body and radiator and as you can see from pic I also have top closed off. Insuring all air is going through radiator.

Well posting pic not working... so just take my word

[adileo]

Worked now

[Ken/Alabama]

Could be ignition timing is to low.

[petehoovie]

Is the engine a fresh build? Have the coolant sniffed for hydrocarbons....

[Mike in AZ]

Heated air not escaping from under hood, keeping engine temps up. Not enuf air flow out of engine bay at higher speeds?? Just guessing. Mike

[Mart]

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Could be timing. I had a 46 that behaved like that. It had a french motor which has a loadamatic style vac only distributor. Only thing was, the vac canister had failed, so no advance at all. It overheated while driving it home which was about 100 miles. It was ok on local journeys and I did find the problem and fix it.

Mart.

[adileo]

Thanks. Engine has 35k miles since rebuild.

I have a helmet distributor (bubba built few years ago). I’ve never checked timing on this type of distributor. How is it done?

I have a timing light and have used it on the 52 F1.

[Frank Miller]

Water flowing too fast through the radiator. I have had my car get hot and have coasted down hill with no change in temp and then put it in gear up the next hill and it cooled down because the water was cooling in the radiator. Your radiator may be getting marginal but then mine may be too.

[TJ]

I had a 65 Mustang that did the same thing. The radiator had a bunch of plugged tubes. Over time electrolysis and crud from the block can plug the tubes.

[19Fordy]

Mike in AZ makes a good point.

If you could run the car without a hood their wouldn't be any trapped air which constantly recirculates. I know that's not a viable solution. Another idea is:
If there is a metal splash pan or sheet metal piece behind the chin pan
and below the radiator, remove it and see if there's an improvement. It looks like this:
http://lbcunited.com/earlyford2/prod...e43d1648c891b6

[adileo]

Originally Posted by 19Fordy

Mike in AZ makes a good point.

If you could run the car without a hood their wouldn't be any trapped air which constantly recirculates. I know that's not a viable solution. Another idea is:
If there is a metal splash pan or sheet metal piece behind the chin pan
and below the radiator, remove it and see if there's an improvement. It looks like this:
http://lbcunited.com/earlyford2/prod...e43d1648c891b6

Good thought Fordy, but my cars pan was removed already.

[19Fordy]

Ok. Seems like upside down thinking but tape a piece of thick cardboard where the
splash pan should be and see what happens. Also make sure the sheet metal side panels on each side of the grille are in place. They help funnel the air into the radiator.

I have often thought about installing an unobtrusive air deflector below and just in front of the radiator to deflect fresh air up into the radiator. It wouldn't have to be very big. Just a piece of sheet metal with a lip. Bet it would help. Try it.

[adileo]

Like this

[expavr]

Originally Posted by Mike in AZ

Heated air not escaping from under hood, keeping engine temps up. Not enuf air flow out of engine bay at higher speeds?? Just guessing. Mike

I agree. I'm not familiar with how the engine compartment is configured on the cars but on the tonner there is a very large opening between the inner fenders and the cab on either side of the truck where the inner fenders attach to the cab. These two openings look like ducts that were meant to allow the airflow to pass thru the engine compartment without restriction.

[tubman]

When I got my '51 club coupe in '87, it was well-preserved 65K mile car. It did however, have a tendency to overheat occasionally. I had the radiator re-cored (it wasn't too expensive back then) and have never had a bit of trouble since. It seems it doesn't take too much to cause radiator problems. I have to believe this had more to do with the number of years elapsed rather than the miles.

[19Fordy]

Originally Posted by adileo

Like this

Not sure if your photo shows an air deflector/scoop or the cross member.
However, if you are showing a scoop, that's what I had in mind.
Looks like you are thinking ahead of me.

I finally replaced my OEM 40 radiator with a Walker Cobra radiator in Dec.1990 and found much improvement. Radiator cost $481.50 back then. Fan shroud was $52. 10 pound cap was $12.50. Because I am running an 8BA, Walker made the top radiator hose "pipes" to fit. Also, had water pumps rebuilt by "Skip" Haney here on Fordbarn. I am not using thermostats. Set up still working fine.

Perhaps a new radiator is in your future.

[adileo]

Tell me more about the shroud. Will it fit stock radiator? Where did you get it?

That may help the fan pull better.

[Bored&Stroked]

Originally Posted by adileo

Tell me more about the shroud. Will it fit stock radiator? Where did you get it?

That may help the fan pull better.

That would tend to help in traffic - it is probably not going to help in your situation. Your situation sounds more like the overall capacity/capability of your cooling system to handle the heat generated under load is too little. One thing that can cause it is too much restriction in the thermostats -- and therefore potential cavitation in the pumps. I would remove the thermostats and see if the situation changes in any real fashion - could tell you a lot.

I also think that overall airflow through the radiator and even heat in the engine compartment are not the issue -- as there is a LOT more air moving when you're going down the highway. Now, the comments about the radiator maybe not having the capacity to cool the amount of heat generated at highway speeds - could be it (due to it being plugged or just plain old).

What a lot of people don't ponder is that the overall cooling capacity of some copper/brass radiators can be reduced over time due to corrosion of the soldered joints between the fins and the cooling tubes. This is why you can recore a radiator that doesn't show tube blockage - and the new core can cool a lot better than the old one (even with the same core thickness, rows of tubes, etc).

[Jason in TX]

These cars didn't overheat when new. When new, it had the same airflow, so I wouldn't say that the hood and the shrouds and the engine compartment is suddenly now the problem.

Something is wrong with the engine or cooling system. I would guess timing.

These helmet distributors are "backwards" in regards to advance. Normally in an ignition system, the faster you go, the distributor advances.

Ford used a leather disk to act as a brake to prevent the distributor from advancing.

Try loosening the screw on the side of the distributor and nudge the advance back a little. Then drive and see if you get better performance. You don't need to move it much.

A little reading on the distributor.
http://www.bubbasignition.com/helmet--32-41-1.html

More overheating trouble shooting tips:
http://www.vanpeltsales.com/FH_web/f...oubleshoot.htm

[adileo]

Thanks gents - the last two post have provided me some easy possible fixes. Bubba also suggested I try the vac brake.

I will do a process of elimination, cheapest and easiest first.

Probably won’t know results till next week. I’ll post findings.

Thanks again!