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

Hi, In my 1937 8 cylinder 120, the cooling water boils after a short load on the engine. what do you say? is the cooler the problem? Water pump is new. Engine completely overhauled.

Greetings and thanks Mike

Go over and recheck the torque on the head bolts. It may not necessarily leak, but heat transfer from the head to the block and exhaust gasses close to the water in the head may cause it to heat up too much. Properly torqued head bolts not only keep the seal but help separate the hot combustion chamber from the coolant and also prevent any gas escaping into the coolant under pressure allowing bubbling of the system and excess heat. Worth a try anyway.
Bob J.

Check your timing to make sure it's correct.

Also, make sure your exhaust isn't partially blocked.

When I first started the Jaguard, it blew half-burned acorns out of the exhaust pipe!

Is your thermostat installed?

What is the condition of the radiator?

I've tried it with and without a thermostat and nothing changes

Engines normally run cooler with a proper thermostat. If the engine performs well otherwise, you probably have a radiator or water pump issue. Clogged radiators are very common on older cars, especially the ones with rag seal water pumps and non-pressurized systems.`Packard 8s have a water distribution tube inside the block that directs cooling water flow.These can corrode or go missing, which will cause overheating. It's possible the water pump impeller is damaged or has come off the shaft. Late ignition timing can cause overheating. Initial timing can be incorrect or the distributor advance mechanism(s) may be inoperative or out of adjustment.

I'm going to have a new radiator net installed. But I'll try the ignition timing again first.

Greetings and thanks Mike

Be sure the ignition is in good order, and be sure the radiator core isn't loaded with dust, bugs, lint, grass seeds, etc. That stuff can embed deep among the tubes and block a lot of airflow. Dirt dauber nests in the exhaust system can cause issues. A stuck manifold heat valve (Very common issue)can contribute to overheating and flooding. Some cars have tailpipes that are prone to hitting curbs or other obstructions and can be bent in such a way that exhaust flow is restricted. Mufflers can be plugged with mouse nests, acorns, and other odd stuff.

I would back flush the radiator to remove any possible scale in the system that would block the tubes. While you’re at it, back flush the heater core as well. And unless you know its good, replace the thermostat as well as it could be faulty. I’ve seen new ones that were stuck closed.
Doc

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