VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Oil in my coolant!

I recently discovered my coolant getting muddy, no longer clear green. My coolant appears to have motor oil mixed in it. I don’t see water on my dip stick. Is this a bad head gasket hopefully? Any suggestions on how I should proceed?
Thank you
Michael
38 Master Sport

Coolant is not a good lubricant so I would not want to risk driving the car at this point. You could drain some of the oil into a clear pop bottle and see if the coolant separates out. I did this to verify that I had coolant in the oil once. You can buy kits that will check for exhausts gasses in your coolant. If there are gasses in the coolant also it is most likely a head gasket.

Might be worth running a compression test.

Could also be from the rocker arm oil supply line, which runs through the water jacket on it's way up to the top of the head.

Thank you gents, I can:
1. Check motor oil for coolant and if coolant present what next
2. Do compression check, if low then what
3. But not sure how to check rocker arm oil supply line. Is that the line that runs past the lifters under the side cover?

I am learning how to work on my engine by necessity and hope it is jus the head gasket and nothing worse. I finally got my 38 in the road after a year and now this. I know she is old and needs tlc but I’m trying not to create more issues trying to fix her.

If a cracked head or head gasket one of the spark plugs will look diferent from the rest deposit wise.
My next step would be removing the push rod cover and checking the fitting around the roker arm oil line to block.

The key to troubleshooting this is to investigate all the areas where the oil and coolant can mix.

Ole's suggestion is very good. The oil line that goes through the head to send oil to the rocker arms passes through the coolant that is circulating in the head.

I would test that by disconnecting both ends of that tube. Plug or cap one end. Use a hand vacuum pump and apply suction to the other end . If there is a hole where that tube passes through the head you will pull coolant into the line going to the vacuum pump. At a minimum it will not hold vacuum.

Without some more study, I cannot think of other areas where the oil and coolant passages are adjacent or interface. Hopefully the real experts will jump in with some ideas.

After I posted my note about a compression test I realized that it will probably not help troubleshoot this problem. There are no oil passages at the head to block interface on these engines.

If there is a bad head gasket it could let coolant get into the oil. That is not a path for oil to get into the coolant.

I hope it’s not major, I have little to no experience with this type of issue. I will keep you all posted on what I find
Thanks again

Reach out to some of your fellow VCCA members in the Bay Area.

I’m not aware of anyone in east contra costa. I will investigate using the suggestions and start doing research on my own as well. I’m hoping not to have to rebuild engine but if I do so be it. Their are worse things in life like melting in front of the tv.
Keep you all up to date when I discover my issue or issues

Oil in the coolant means the oil has more pressure than the coolant, Ole's suggestion is most likely. The rocker oil feed is a small copper tube the passes through the water jacket behind the side plate and then up to the rocker gear. It is common for this tube to fatigue and leak as it goes through the water jacket. Not a 5 minute job to replace it.
The vacuum test connected to the top with the engine stopped is a good check.
Tony

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