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Foam from coolant overflow - 1937 Special


70sWagoneers
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Hello, Ive got a 1937 Special with the ball bearing type water pump. For a few months now, but increasingly more common, I will get foam from the coolant overflow. Propylene glycol coolant. The temp gauge doesnt read hot when I get the foam, and when she has run hot (about 210) no foam comes out. So I think Im getting air in the water pump some how to create the foam. I made sure to retighten all my hose clamps. And I dont see any cross contamination in the oil or the coolant. There is also evidence that the pump shaft is leaking out the snout of the pump. Could this be the culprit? So that led me to looking at NOS water pump kits on ebay.... and my question would be is there rubber seals in the water pump and would you trust the rubber seals in an 80 year old kit?

Thanks

James C.

Edited by 70sWagoneers (see edit history)
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3 hours ago, 70sWagoneers said:

There is also evidence that the pump shaft is leaking out the snout of the pump. Could this be the culprit?

 

Yes. It is even likely that this is the culprit, particularly if it is a significant leak.

 

No packing nut on this one, right?

 

Edited by Bloo (see edit history)
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I can't speak for propylene glycol (I won't use it in a soldered system--only ethylene glycol==EG), but EG will foam at speed in an UNpressurized cooling system, displacing coolant and sending much of it out the overflow.  My 1934 Pierce came to me 12 years ago with a 50/50 EG dose, and lost 1.5 GALLONS every 120 miles between freeway pit stops.  I don't need anti-freeze so use distilled water + Pencool additive for corrosion protection and water pump lube, and have to add about a quart every 600-700 miles.  A good friend in Michigan drains antifreeze every spring and runs the same mix as I with the same results, then puts the antifreeze back in the fall.    

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Does anyone know what the seals are made of in a NOS water pump kit? I keep reading about a carbon block and pictures of the kits look like they have a sandwich of fiber washers. If the seals are rubber, i assume theyd be old and brittle. But if the seal is carbon, i figure it would still be good for its age.

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I suggest that you first check the bottom hose (suction side of the water pump).  If it is old and soft, it may collapse and cause cavitation and foaming. 

Hoses in later model cars usually have a spring inside the bottom hose to prevent this from happening. 

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The seal is a rubber, carbon and spring assembly and it is crucial that it rides on a perfectly flat surface on the impeller.

For the most part, this is not a  "do it yourelf" job since the flat part has to be "optically" flat. This is done on a special lapping machine.

 

Unfortunately, the manual does not show the later pump with a "mechanical" seal - one that is like what you need.

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Thanks. I talked to some vintage pump rebuilding services today. The price they ask seems well worth both them machining sealing surfaces and fitting more modern seals. He said the newer seals were a direct fit replacement so nothing is altered. Now i just gotta get that pump outta there!

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My 1929 Buick coolant would foam and overflow before I added a thermostat. It appeared that the coolant was circulating way to fast with little restriction. It did this for years at cruising speed. The inline thermostat fixed my issue immediately.

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I feel that it is much easier to remove the pump, thermostat housing and fan as an assembly.  Getting the fan bolts out is hard on the knuckles and radiator.

Getting the fan back on is a challenge; aligning the fan, pulley and pump flange. Doing that "on the bench" is easy.

Protect the radiator with a piece of cardboard.

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On 6/27/2018 at 1:18 AM, 70sWagoneers said:

Could i perhaps replace the rubber seal in a NOS kit with fresh rubber? I have the lower hose with the spring and non of my hoses are leaking?

 

Hi,

do have available a NOS repair kit that I bought for my early 1938 Special with 248 motor. It comes with all new seals that look fine plus new bronze bearings, shaft and impeller etc. if interested send me a PM.

Rodney (from down under)

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  • 3 weeks later...

Thanks Rodney. I have the pump rebuilt by My Classic Car Trader, LLC and just got it back on yesterday. So far, after a flush, and refill, I haven't seen any foam or leaks. So for the price, it was worth it to send it out. Time will tell tho :)

Thanks

James C

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