oil in coolant on 40 ford

[Thomas Sargent]

Awhile back I installed an overflow plastic tank on my 1940 ford Four door flathead. System works great, system is still no pressure, but overflow tank allows me to completely fill the radiator and has prevented spills. The tank is semi clear white plastic. I have noticed a very small amount of oil film on the top surface of the coolant in the tank. After about 4 months of service, I removed the tank and cleaned all the oil film out. A few weeks later I notice the oil film has returned. Do I have a failing head gasket or is there a crack somewhere in the block allowing this. Amt of oil is very small and not causing any issues. NO sign of coolant in the oil pan. Thoughts? Thanks

 

[The Art Doctor]

Water pump lubricant?

 

[alchemy]

That would be my guess.

 

[Kurt in NJ]

The water pumps get their bushings oiled from the engine oil on original stock pumps so it is possible that the water pump could put oil into the coolant— it’s not pressure oil, just splash from timing gear

 

[farmertom]

The water pumps get their bushings oiled from the engine oil on original stock pumps so it is possible that the water pump could put oil into the coolant— it’s not pressure oil, just splash from timing gear

At what point did ford stop using splash oil from timing gear to lube water pumps?after flathead era? curious.

 

[alchemy]

Had bushings in the pumps up to 48. In 49 they got bearings. I don’t do 8BA’s so I don’t know if they have external oiling or are sealed.