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Old 03-31-2019, 05:17 PM   #1
Zenwren
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Coolant in oil but system holding pressure?

**Long story warning**

Over the winter I picked up a very nice '69 C10 with the factory 350 short block, L98 Aluminum heads, and an Edelbrock Performer RPM intake. There was plenty of snow on the ground so I bought it with no test drive, creeped it half a mile down the road to a storage unit and left it there.
When I bought it, the guy mentioned that the intake was sucking air so he had replaced the gaskets. He later mentioned that it leaked coolant the first time so he did it twice. I asked if he changed the oil and he said no (thanks a lot!).
I went out and changed the oil a couple weeks later and sure enough about a pint of clear water came out before any oil I refilled the oil and started it up, the new oil still looked pretty milky so I shut it off right away and left it.
The next time I came with a car trailer, I pulled the drain plug and no clear water came out, but the oil looked pretty cloudy and gross for being new. Added fresh oil, loaded it up and trailered it home.
The fresh oil is a little better but still looking milky. I hooked up a coolant pressure tester, and after discovering a couple bad hose clamps it held at 15psi for 3 hours and only dropped about 1/2 a pound if that. Pulled the plugs and didn't find any "steam cleaned" ones.
My next step is to let it sit for a couple days and pull the drain plug to see what has settled out. If I don't get any worrying amount of water out I guess I'll take it out and get it good and warmed up. Maybe from all that cold weather short starts and stops it got all full of condensation/sludge that needs to be worked out? Is there any way water could be getting into the crankcase if the system is holding pressure? Any thoughts? What are the odds my bottom end is trashed from running with that much water in it? I doubt he drove it at all after the initial intake change being winter so it probably had a half hour or more of low rpm running with water in it.
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Old 03-31-2019, 10:23 PM   #2
LockDoc
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Re: Coolant in oil but system holding pressure?

Quote:
Originally Posted by Zenwren View Post
**Long story warning**

Over the winter I picked up a very nice '69 C10 with the factory 350 short block, L98 Aluminum heads, and an Edelbrock Performer RPM intake. There was plenty of snow on the ground so I bought it with no test drive, creeped it half a mile down the road to a storage unit and left it there.
When I bought it, the guy mentioned that the intake was sucking air so he had replaced the gaskets. He later mentioned that it leaked coolant the first time so he did it twice. I asked if he changed the oil and he said no (thanks a lot!).
I went out and changed the oil a couple weeks later and sure enough about a pint of clear water came out before any oil I refilled the oil and started it up, the new oil still looked pretty milky so I shut it off right away and left it.
The next time I came with a car trailer, I pulled the drain plug and no clear water came out, but the oil looked pretty cloudy and gross for being new. Added fresh oil, loaded it up and trailered it home.
The fresh oil is a little better but still looking milky. I hooked up a coolant pressure tester, and after discovering a couple bad hose clamps it held at 15psi for 3 hours and only dropped about 1/2 a pound if that. Pulled the plugs and didn't find any "steam cleaned" ones.
My next step is to let it sit for a couple days and pull the drain plug to see what has settled out. If I don't get any worrying amount of water out I guess I'll take it out and get it good and warmed up. Maybe from all that cold weather short starts and stops it got all full of condensation/sludge that needs to be worked out? Is there any way water could be getting into the crankcase if the system is holding pressure? Any thoughts? What are the odds my bottom end is trashed from running with that much water in it? I doubt he drove it at all after the initial intake change being winter so it probably had a half hour or more of low rpm running with water in it.

I wouldn't think a pint would be enough to get up into the bearings and stuff while it was sitting. I would say the reason it is still milky is because you started and ran it before changing the oil. The water would then be distributed throughout the engine and it will take a while to get it all settled out. I don't know if there is an additive you can put in the crankcase to absorb the moisture or not. You might do a search on it in Google or YouTube.

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Old 04-01-2019, 07:55 AM   #3
rockyrivermark
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Re: Coolant in oil but system holding pressure?

Yep. Change oil and keep and eye one it. It oil levels rise then coolant is mixing in oil somewhere. I would guess the intake gasket since PO had trouble with one set of gaskets already.
If you don't clean those mating surfaces really good. And use proper torque sequence she will leak into oil for sure
Don't use gaskets for front and back of intake. Use permatex ultra black there. 1/4" bead and run it up into the gasket a 1/4". Let it set 24 hours to set silicone cure before stating engine.
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Last edited by rockyrivermark; 04-01-2019 at 08:13 AM.
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