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My 32 is overheating when in bumper to bumper traffic. Temperature have been no higher than 80. Regular road speed and hill climbing no issue. I had the engine rebuilt last year and it was running warm. Recored the the radiator with a modern core. No problem if I'm moving doen the road.

Noticed the last time I took off the radiator cap, and the coolant was foaming. It had not overheated, and temp was a mid gauge when this was observed. I had traveled about 17 miles. I use a mixture of water and anitfreeze.

I am getting the water pump rebuilt to eliminate the packing leaking slightly.

Any ideas?

Air getting into the system somehow? Bad headgasket maybe? (Shot in the dark since the motor is new, probably not.)


If you have air in the system, it reduces its cooling efficiency. If your packing is leaking, maybe enough air is getting in there?

I have no experience with motors that old, but i wouldn't expect any foaming with just AF and water.

I would think that foaming would point to a head gasket. I had a car with the exact same symptoms. Was leaking pressured cylinder gases into the water jacket from a break in a head-gasket. Foaming and or bubbles would be seen at the radiator neck.

If there is a question of leaking head gasket, might be worth investing in a combustion leak test kit to rule it out. Amazon and Napa have them.

When you had the engine rebuilt did they strip the block chemically--to make sure all rust particles were out of the cooling passenges?

The block was stripped when it was rebuilt.

The mechanic who is working on the car now has a leak test. He did one last year right after the rebuild and I assume he will do it again with the recent foaming.

I just had my engine redone, new gasket etc did the machine the surfaces on the block and head?

All flat surfaces were machined.

Try re torquing the head and see if that helps out.DR

Tbirdman,

Most likely causes, combustion gasses getting into the coolant via a head gasket or block / head leak or air getting pulled in though the pump packing.

I'd check for combustion gas leaks first using a simple tester from NAPA:

arrowheadradiator.com/head_gasket_or_combustion_leak_test.htm

Also I'd make sure the fan belt is tight, 1/2" to 5/8" play when pushed on, on the right side. If the belt is loose it may not be circulating enough coolant and pulling enough air thru the radiator core at lower engine speeds, causing coolant to boil in the back of the block and show up as foam in the top of the radiator.

Regards,

Dave