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Foamy oil. OH NO!


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I got around to changing my oil and going through the winterizing steps before the temperature drops, and when I drained my oil, I found a slight amount of foam on the top (the last bit that came out.)


I've never noticed this before, and I know the head was rebuilt around 2009, so I'm hoping it's not head gasket that was screwed up somehow.. Obviously some kind of contaminants.


Compression check was up about 20 PSI dry from my last check after trying out some different stuff, and I now average about 155 psi dry compression across all 4 cylinders with no more then a 5 PSI variance between cylinders. I re-torqued the head for good measure when getting ready to do my valve adjustment.



It's been a little colder then usual lately, so i'm really hoping the general consensus is condensation in the crank case. The truck runs perfect and only has a slight stumble (probably carb jetting) when cold and idles perfect. I have a decent amount of water in the exhaust, but I'm nearly 100% sure that it's all condensation, as it pretty much disappears when warm, and its not anti-freeze.





The only reason that i suspect I MAY have a headgasket issue is that I have a consistent cooling system leak ever since I replaced my old radiator cap. I now have drips from the thermostat housing, and an unknown leak from the heater valve/heater core that have both been tested and don't leak anywhere near 20PSI.

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Your PCV may be stuck, blocked, not hooked up or just not working. Without it, water and gas vapors and combustion blow by condense inside the block.


Check the rad cap it may be leaking vapor. Also do you have a coolant recovery system? Did you know that sticking the over flow hose in a bottle isn't a recovery system unless you empty the overflow back into the rad yourself? You need a special rad cap for the coolant recovery system to allow it to siphon back into the rad when it cools.

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Foam on top isn't coolant- coolant emulsifies through all the oil, or pools at the bottom. Milky appearance. Not foamy.


Foamy oil nowadays can be caused by mixing brands, or more commonly by mixing pre SN type oil with SN type oil. Oil companies quit even trying to make oil cross compatible after the latest EPA requirements.

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Well, I'm glad the general consensus is not head gasket, since that would be about the worst thing, although I didn't think it was that.



Don't remember if I added any off brand oil on top, but it's possible since I have a lot of leftover oil on the shelf in my garage.


I'm gonna go look into the PCV system now

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