Cool/Heat: 29 commander 6 overheating?

[rwhite]

I recently bought a 29 commander 6 . after filling the water up and letting it idle a bit it started steaming and spilling out through the overflow. the cap is ornemental and missing the gasket someone tried to put a new cork gasket in place however it has a sqaure cut in the middle where there is a nut for the ornament? im new to these old cars and have heard it needs a zero pressure system like a tractor the temp gauge stayed in normal range so my delima here is can i make my own solid gasket and it be alright. or do i need to find another cap for it . or is there another problem?

[altair]

I don't know the details of a 29 but comparing it to a 26-27 model T the radiator cap is non vented and the overflow tube serves as the vent. If you fill it over the vent tube it will spit over until it is where it likes it, it should then settle there. When the coolant gets to a level below the vent system and continues to over flow may indicate an over heating issue and that is a separate issue of investigations.

[doofus]

There are tools to test for exhaust gasses in radiator, might save you some head scratching. most large parts houses have them to loan. Luck Doofus

[nvonada]

+1 on what the previous two posts said. The cooling system is NOT pressurized and has an open vent. The only source of pressure to push the water out is thermal expansion as the water heats up (overfull) or if the head gasket or a crack in the block is letting compression or exhaust gasses into the water jacket. Obviously you are hoping for door #1 here.

Next stop is figuring out if the car is actually overheating. Just sticking a thermometer in can help with that. If the system is not able to cool the car well at idle there could be blocked tubes, an eroded water pump impeller, rust/mud/crap in the block, or even a timing problem. I am currently helping my dad get his 39 De Soto running and we found a good three inches of rust, metal bits, and mud in the bottom of the water jacket. Plus the fun of changing the water distribution tube but that is getting way off topic.

Nathan

[altair]

Because these engines were designed to suck in air when cooling even into the 70s the oxygen in the coolant will react with the cast iron components causing oxidation (rust) that can form inches deep in the bottom of the block. Even aggressive flushing may not remove it without removing the expansion plugs. Later models of cooling systems are designed with a closed system so that oxygen can not re-enter the system. The earlier cooling systems can be modified in the same manner.

If the expansion tank is allowed to run low or empty the same condition will occur, it must be kept at least half full.