Overheating

1

1965 Mustang

Member
This has probably been addressed many times before...
My 29 A (with original motor but with 4 blade fan) constantly blows all the coolant out the over flow or the top of the radiator. I have flushed the cooling system several times, and the ignition timing is correct. When the engine is running with a full radiator (before everything blows out) there seems to be a lot of air bubbles coming up to the top of the radiator. I am thinking exhaust or compression pressure is in the cooling system. However engine compression is good and there is no steam out the exhaust pipe or coolant in the oil or oil in the coolant.

Ideas?

Thank you
 
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You're probably right about the exhaust blowing into the head coolant. Have you rechecked the head torque to 55 lbs?
Maybe the gasket needs to be replaced?
 
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You probably have far too much coolant in the radiator. Just need to have enough to cover the tubes in the radiator. Run it for a while and let it seek its level.
Pull the fan belt off and see if the bubbles etc... stop. With the radiator being so full the action of the impeller may be causing the bubbles you are seeing.
Check the torque of the head bolts.
Get a cheap meat thermometer to see what the actual water temperature is. Many times it looks as if the engine is overheating and puking water out when it is only too full.
 
Some Model A drivers have found that their Water Pump shaft's impeller is too efficient and pushes the water faster than can be digested by the radiator. Some solutions have been to drill holes in the impeller; shave a bit off the impeller.

I (and a number of others) have chose to do what some race car drivers have done - install a 'coolant recovery system'. Mine consisted of a narrow (anti-freeze shape) 1 gallon container, laid in the cradle of the driver's side engine pan, opening toward the radiator, and running a clear flexible hose from the radiator's over-flow tube down to and inserted into the 1 gallon container. Every 100 hundred or so miles, I would stop and pour the jug's contents back into the radiator.

Under normal circumstances and local (i.e. under 45 mph) I never had a problem. But when cruising the highways at 55 - 65 mph, for sustained lengths and distances (5 hours - 250 miles) I did have to deal with the 'over flow' problem. My 'Coolant Recovery System', while primitive, worked beautifully for my entire trip to Alaska and back, and for years afterward.

I was running a 'C' engine (from my '34 Ford Sedan) with a 'B' water pump. The 'B' and 'C' water pumps have a much bigger impeller than does an 'A', so the reasons that may have caused my overflow, may not be the same reasons that causes your overflow from a stock 'A' engine.

- Doug Vieyra, Eureka, Calif
 
Had the same problem. I found two issues - a hole in the overflow tube (mid depth of the upper tank) and no baffle in the fill neck. Even when filled to just above the core, it would puke water out the overflow tube.

My radiator shop replaced the overflow tube (install so the top is just below the radiator cap) and installed a baffle in the fill neck. The baffle keeps the flow from easily getting to the top of the overflow tube. This solved my problem. Good luck.
 
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