Packard Forum Index » Pre-War (1899-1942)

The threads on the end that goes into the block are not normal rolled threads. You thread the stud in until you run out of thread, and that seats the end face of the stud against the block for a liquid-tight fit. I'd still use Permatex #4 or equivalent just to be sure.

Dear mgrambo:

Welcome to the world of old metal. When they were built no sealer was required, although some makes (Ford V-8) specified using sealer on head bolts in the service manual.

Given the motor is together, here is a work around. Drain the anti-freeze and fill the cooling system with straight water to cover the top of the radiator tubes. Leave the cap loose. Run the motor and then let it sit for a few weeks - given your garage is heated. After a time particulates should fill the porosity that is causing the leaks.

Also, do not put a high pressure radiator cap on. The system is not designed to operate under anything higher than nominal pressure.

If you still have a problem then add a half teaspoon of very finely ground black pepper and repeat.

I have actually had these old motors leak around studs even when using sealers. Sometimes the leak is coming right through the castings.

Hope this helps.

Your technique worked great thanks for your help