Oil in coolant

[Ralph S.]

Hello


I got some oil in the coolant after last time I drove the car. It's a 41 with a 46-48 59 AB Merc 100HP motor. Is there any chance a failed water pump gasket would allow some oil to get into the coolant? I took the water pumps off to see what they were and if they were the original bushing type or the new sealed bearing type. I know the bushing type pumps need little bit of oil to lubricate them. Anyway, I'm sure the pumps that were on the car are the sealed bearing type, have Bob Drake name on them, not sure how long they have been on the car. I would imagine that the gaskets that come with the new style pumps seal off the oil passage. Gasket on the passenger side looked pretty bad so I'm hoping that it was allowing little oil into the coolant. Is that a possibility? Other than that pumps seem fine, spin quiet, feel tight with no play.

[RKS.PA]

Ralph, is this a new problem for the car? Are you sure it's oil and if so, how much?

[51 MERC-CT]

Are you talking about the water pump to engine block gasket? or the pump seals?

[Ralph S.]

New for the car. I check the coolant regularly, pretty much before every start up, along with oil. Never noticed it before. Pretty sure it was oil, black spots floating in the coolant looking through the fill neck on the rad. Drained coolant confirmed it. Not a whole lot, but enough to concern me. 51 Merc-Ct, I was referring to water pump to block gaskets.

[RKS.PA]

In your post on 4/06, you mentioned getting your radiator fixed and that you were looking for sources to help you in your part of NC. What kind of issues are you having with your radiator that you feel need attention, in addition to the oil in the coolant?

[Ralph S.]

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I noticed the radiator is starting to develop some small leaks. Since I took it out in order to create more working space for pump removal I figured it would be a good time to have it refreshed. Definitely looks like it could use it.

[51 MERC-CT]

Originally Posted by Ralph S.

51 Merc-Ct, I was referring to water pump to block gaskets.

There is not any part of the gasket that presents a surface to any source of crankcase oil.

[Ggmac]

Was it enough oil in water to noticeably reduce the oil level ? A combustion leak could give small amounts of contaminates in the water . If you didn't overheat it and the radiator redo was just cause it needed it , you need to start looking for bubbles in the water while car is running , after a warm up , let cool and pull plugs to check for moisture .

[Zeke3]

Originally Posted by 51 MERC-CT

There is not any part of the gasket that presents a surface to any source of crankcase oil.

My 21 stud 1937 engine block has an oil hole from the timing gear area to each water pump and the water pump bushings are lubricated by the oil thrown off the timing gear. I believe the 1938-48 engines used the same method to lubricate the water pumps, per Joe Abbin's flathead book. So there would be an oil hole through the water pump gasket on the first and second generation engines.

[Ralph S.]

Are the holes I'm pointing to the holes that would have had the purpose of oiling the bushing on the original style pumps? I'm pretty sure I have the updated sealed bearing pumps. Seems like the pump to block gaskets covered those holes. Gasket on the passenger side was pretty bad so I'm hoping that's how little oil was able to make it's way into the coolant. If not I guess I'll have to look at a possible more serious issue. Also includd pics of water pumps that were on the car.



@Ggmac

Definitely not loosing enough oil to notice a reduced oil level. Car didn't overheat, and I would like to rebuild or replace the rad since I have it out of the car. Pretty much whole cooling system is out, so might as well refresh everything.

[Zeke3]

Ralph, those two holes appear to be the same as my engine has, smaller hole on the right side and larger diameter hole on the left side. The oil at those holes is not under any pressure, so I would think a gasket without a hole should block it pretty well.

[Ralph S.]

That's what I was thinking. Gaskets for a sealed bearing pumps, which I believe I have seal off the oil feed hole which is no longer needed. With the hopes that the gasket failed I'm going to get new gaskets, reinstall the pumps(since they seem and feel to be ok) along with new hoses. Rebuild the radiator if I can find a place around here that will be able to do it. Buy another one if need be. Put it back together, flush for good measure, install new thermostats and hope for the best. If the issue persists than I guess I may have a more serious problem.

[Aarongriffey]

I think ‘49 was the last year for the oil hole. Maybe 50.
Anyway there were 8BA bushing type Warner pumps. I found one on an 8RT in a 51 pickup which caused us to think it may have a ‘49 engine.

[Aarongriffey]

Water pumps, not Warner pumps.