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model A over heating


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Hi all!

I work at a GM dealer and don't know much about Model

A Fords, but for some reason I agreed to work on a couple of them. Both of them are over heating and I don't know why. One of them will not restart when it is warmed up. Does anyone have any suggestions?

Thanks Daniel

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Set timing, clean or replace radiator, power flush block, check for head gasket leak, check for brake drag. Maybe not in that order but a properly timed A with good intact cooling system will not over heat. Is the one that won't start hot turning over or doesn't crank?

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Thanks, checked all that and seems ok , unsure about radiator thinking of sending it to a radiator shop for cleaning. The one that doesn't start cranks ok, but I didn't get a chance to see if it had spark. Will try to keep you posted.

Daniel

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When you remove the top hose look to see if someone put an inline thermostat in the hose sometimes they get cocked sideways. try a caustic soda radiator cleaner because sometimes the waterpump is greased too much or with water pump grease which is a big no no on an A. When Hot and if no spark change condenser and then coil.

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My Dad's Model A had an overheating problem with a new radiator and many other new parts. We finally determined that it had a bad head gasket that was leaking just enough combustion gases into the cooling system that it kept raising the coolant level in the radiator upper tank and forcing the coolant to run out the overflow.

A Block Test kit was used to see if there was combustion by-products in the cooling system. There were.

A new head gasket solved the problem. He can run at 45+ MPH all day now in the summer with no overheating at all.

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I had trouble with a plugged muffler.The normal replacment Muffler has two discs with small holes drilled in them to make the model a sound,they are very high in backpressure and if a disc comes loose or rusty, etc.it will cause overheating.

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After more testing on the over heating I found that if I drive it at 40 to 45 mph it blows the water out to low enough level that it over heats in about 2 miles. Filled it up and drove about 8 miles at 30 to 35 and never blow out a drop and ran cool(a fun drive too). Have been advised to grind 1/3 of fins off water pump so it will not over fill top tank of radiator and pump water out. What do you all think? I was thinking that a new radiator might flow a little better and fix the problem .

Thanks Daniel

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I have heard of grinding off the fins, but I think that is patching it without fixing the real problem.

I suspect that you have a radiator that is partially clogged.

From the MAFCA Website Tech Section linked above:

"I would first test your radiator for flow rate. It should have a flow rate of about 36 to 38 gallons per minute. You can test the flow rate by plugging up the top goose neck and the bottom outlet and then fill the radiator. It should hold about 1-1/2 gallons in the radiator. If it takes less than 1-1/2 gallons then you have clogged tubes. Remove the plug from the bottom outlet and the 1-1/2 gallons should drain in about 4 seconds or less. If it takes longer to drain it indicates you have restricted tubes. If the flow rate is good or close, the other problem of overflow at higher speeds could be caused due to a missing baffle in the top tank of the radiator. This baffle was placed inside the top tank about 1 inch down from the top of the filler neck. The baffle prevents the water from being pushed out the filler neck by the high pressure of the water pump pushing water into the top tank. Sometimes when the radiator is repaired at a radiator repair shop they forget to reinstall the baffle or the baffle could have rotted out. When you look inside the filler neck you should be able to see the baffle. This must be in place to prevent water pushing out when driving at higher speeds. Rodding the tubes is a job I have always had done by an experienced radiator repair shop. I know they boil the tank first in a hot caustic solution before removing the top tank for tube rodding."

I would test the radiator. If that is the problem, as I suspect, take it to an old fashioned radiator shop and have them fix it. In my experience, they will probably make it work like for under $100. Good luck.

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<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Daniell68</div><div class="ubbcode-body">After more testing on the over heating I found that if I drive it at 40 to 45 mph it blows the water out to low enough level that it over heats in about 2 miles. Filled it up and drove about 8 miles at 30 to 35 and never blow out a drop and ran cool(a fun drive too). Have been advised to grind 1/3 of fins off water pump so it will not over fill top tank of radiator and pump water out. What do you all think? I was thinking that a new radiator might flow a little better and fix the problem .

Thanks Daniel </div></div>

This is _exactly_ what my Dad's Model A did. He had a bad head gasket. Do the "block test" where you check for combustion gases. It only takes a few minutes.

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That was a misstake i made one and a half month ago. To much grease.

And my engine was overheating.

But the problem solved itself actually. I didnt used my A for almost a month cause a mechanic had promised me to help me with some other stuff and would help me with my radiator to. Yesterday i started the engine and drived for a while and the overheating was gone.

I droved for the whole day and i was sure to check sometimes. And it was actually gone.

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Thanks for all your help on the over heating The owner decided to try just driving it at lower speed where it is not over heating and enjoy putting around town. On the other car that doesn't start when it is hot it does have spark and cranks fine. Did these cars have trouble getting the carburator too hot and the fuel boiling out?

Daniel

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The owner can do whatever he wants to do with his cars, but if you systematically check out all of the variables, you can fix a Model A easily. It is not normal to have these types of problems. With gravity fuel feed, I have never experienced any type of vapor lock, and don't think that it should be a problem, but there might be others who will disagree.

I recently drove my Model A at highway speeds for 100 miles per day for 5 days on the Sentimenal Tour. The only problem that I had was convincing the other tour participants that I did NOT have an overdrive transmission in the car. Model A's were designed to drive at 55 to 60 miles per hour when new and in properly restored condition, they still can do it. (It does help to have a hill to go down to get it up to 60 quickly.)

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  • 4 weeks later...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: austincar6</div><div class="ubbcode-body">What is the GM dealer doing with the Model A Ford? </div></div>

He wanted to work on a Great car maybe?! grin.gif

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