2G Oil in coolant

[ttravis88t]

Hello, so I was doing a flush to my cooling system and the worst case scenario happened, oil in my coolant, which most likely means blown HG but what’s strange is I don’t over heat, I don’t have white smoke out the exhaust, and my oil dipstick shows perfectly clean oil. At first I thought the substance in my coolant was just radiator sludge but after looking at the bottom of the bowl I emptied it in I could see small amounts of oil beading up at the bottom and it also smelled like exhaust fumes. So I know it’s most likely the head gasket, but I’ve had a buddy tell me that it could potentially be the turbo is bad and it’s allowing oil to mix with the coolant? I don’t know how that would even happen since they shouldn’t even have any gasket or seal to separate the 2 fluids but I wanted to get another opinion. Any ideas? Thank you

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[jakk220]

Yeah most likely head gasket. Just because there is no white smoke and no coolant in the oil does not mean that its not blown. It just depends how it failed.

 

[ttravis88t]

Ok, so due to it being a somewhat small leak what do you think the likely hood is I’m gonna have to get the head resurfaced?

 

[Mech Addict]

If I have this right, the cooling system pressurizes to about 14psig, while oil pressure runs 30psig and up. So a small leak between these two (and nowhere else) in the head gasket (or anywhere they are in close proximity) would end up with oil in the coolant, not the reverse. Sounds like a small leak, and not into the combustion chamber.

Try torqueing the head bolts??

 

[NOSLO2PT0]

Oil filter housing could possibly be leaking

 

[pauleyman]

Boy you guys jump to conclusions fast. You're forgetting the turbo has oil and coolant and so does the oil filter housing. The car drives fine with no symptoms and no smoke? That does not say head gasket to me. Eliminate the other possibilities. Run a compression and leakdown. Lastly do a coolant pressure check. That should tell you objectively instead of guessing.

 

[ttravis88t]

Oil filter housing could possibly be leaking

Boy you guys jump to conclusions fast. You're forgetting the turbo has oil and coolant and so does the oil filter housing. The car drives fine with no symptoms and no smoke? That does not say head gasket to me. Eliminate the other possibilities. Run a compression and leakdown. Lastly do a coolant pressure check. That should tell you objectively instead of guessing.

Ah the wiseman has spoken, so a leakdown test would only show a leak from a headgasket but what about those testers they sell cheap at like autozone that have the blue fluid that will change colors when in contact with exhaust gas coming out of the radiator? I have one in the garage somewhere and would like to try that first. Would those still show a leak even if it’s not the headgasket and it’s from either the turbo or oil filter housing?

 

[pauleyman]

That might help but it isn't definitive. Coolant could get exhaust fumes from turbo too but not oil filter housing. Coolant pressure tester may prove the most useful. Filter housing is very suspect as it's a known problem if somebody overtightens the center bolt.

 

[ttravis88t]

No

That might help but it isn't definitive. Coolant could get exhaust games from turbo too but not oil filter housing. Coolant pressure tester may prove the most useful. Filter housing is very suspect as it's a known problem if somebody overtightens the center bo

now that I think about it. I just changed the oil filter and when taking it off the housing kinda shifted and moved around. I kinda shrugged it off because I didn’t have much time and needed to get to work. But that definitely doesn’t seem like it was supposed to do that. Sounds like that’s my first culprit.

 

[ttravis88t]

Boy you guys jump to conclusions fast. You're forgetting the turbo has oil and coolant and so does the oil filter housing. The car drives fine with no symptoms and no smoke? That does not say head gasket to me. Eliminate the other possibilities. Run a compression and leakdown. Lastly do a coolant pressure check. That should tell you objectively instead of guessing.

So, I got the housing off and honestly the gasket appears undamaged, I don’t see it being the failure point to allow oil to mix with the coolant. What I didn’t notice though is the big bolt that hold the round silver part that has coolant go through it to the rest of the housing was lose enough that I could rotate it with my hand about and inch left and right ( Look at pictures) could this be a place the fluids could mix?
And is there supposed to be a gasket here because there isn’t one it only has the oil filter rubber ring like material on one side

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[pauleyman]

That looks like a likely candidate for oil and coolant mixing. There is a gasket. Looks like it's on the housing. When you reassemble this do NOT crank the center bolt down. You will crush the cooler internally. I don't have my books in front of me but I can look later if you don't have a manual (hint hint if you don't).

 

[NOSLO2PT0]

Replace this gasket and the oil filter gasket gets compressed against that flat section when you tighten it. That big bolt needs to be torque to 29-33ft/lbs

And yes, if that bolt was loose, oil and coolant can absolutely get mixed.

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[ttravis88t]

That looks like a likely candidate for oil and coolant mixing. There is a gasket. Looks like it's on the housing. When you reassemble this do NOT crank the center bolt down. You will crush the cooler internally. I don't have my books in front of me but I can look later if you don't have a manual (hint hint if you don't).

As for the gasket it looks there is a SLIGHT film of rtv. Doesn’t look like it would seal very well. What would this gasket even be called so I can find one online? Oil cooler gasket? And yes if you happen to have a book that shows tq specs that would help tons I don’t have one. Thank you!

 

[pauleyman]

No rtv. There is an oring between the two halves

 

[ttravis88t]

No rtv. There is an oring between the two halves

Looks like someone put rtv on it at some point in its life but yes I see the orange o ring. Looks to be ingood shape no cracks or anything. Still replace?

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[pauleyman]

That's up to you. I know those center bolts are known to come loose. Most of us just tighten them back up and go on.
Btw it's 28 to 33 ft lbs.

 

[ttravis88t]

That's up to you. I know those center bolts are known to come loose. Most of us just tighten them back up and go on.
Btw it's 28 to 33 ft lbs.

Gotcha thanks for the help

Gotcha thanks for the help

So I just ported it and I knicked the side wall where the piston goes slightly. Will this effect anything in a negative way

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[dustyboner]

your screwed now.

not really. I have no idea. i was just gonna say there is some good info on the oil cooler and how it is damaged by over tightening over on the VFAQ

 

[AWD-Tony]

Deburr it and see if the piston hangs up. Should be fine if the piston moves freely.

 

[ttravis88t]

Deburr it and see if the piston hangs up. Should be fine if the piston moves freely.

Yup it’s deburred and piston moves great, just was wondering if it would cause any sealing problems. But from what I’ve seen it shouldn’t effect much

 

[19Eclipse90]

In addition, if the cooler is suspect: How to test an Oil Cooler

 

[jakk220]

That looks like a likely candidate for oil and coolant mixing. There is a gasket. Looks like it's on the housing. When you reassemble this do NOT crank the center bolt down. You will crush the cooler internally. I don't have my books in front of me but I can look later if you don't have a manual (hint hint if you don't).

Replace this gasket and the oil filter gasket gets compressed against that flat section when you tighten it. That big bolt needs to be torque to 29-33ft/lbs

And yes, if that bolt was loose, oil and coolant can absolutely get mixed.

See I think I disagree on this one guys. But correct me if I am wrong. In order for the coolant and oil to mix the cooler would have to have been overtightened and crushed and would need to be replaced. The coolant fins would have to be damaged for them to mix. They are sealed from each other internally. That rubber seal is only to prevent an oil leak from where the cooler meets the housing. The paper gasket would not cause it either. That is only for oil. The center stud has come loose on almost every DSM I have owned and yeah it leaks oil but does not mix.

Boy you guys jump to conclusions fast. You're forgetting the turbo has oil and coolant and so does the oil filter housing. The car drives fine with no symptoms and no smoke? That does not say head gasket to me. Eliminate the other possibilities. Run a compression and leakdown. Lastly do a coolant pressure check. That should tell you objectively instead of guessing.

I have had a ton of blown head gaskets and actually only few have ever put off white smoke out of the exhaust. And that one was completely screwed and lifted the head. A lot of the time it was either pushing coolant from exhaust gases or oil in the coolant. You normally get the oil in the coolant (which is what is happening here) with a blown head gasket because oil pressure is higher with the car on. When the car get shut off the coolant pressure sticks around longer and then it can get into the oil.

I have never heard of coolant and oil actually mixing from a turbo. The coolant just passes through the housing for cooling. So in order for that to happen I feel like you would have to smash the thing with a hammer or somehow have a massive deep crack. I guess its not impossbile, but I have never heard of that actually being the cause.

While I agree it is possible to be the oil cooler, if it is, it would have to have completely failed and need replaced. Thus, most likely I believe its a head gasket. But Pauley is right, a leakdown and pressure test will tell all.

Looks like someone put rtv on it at some point in its life but yes I see the orange o ring. Looks to be ingood shape no cracks or anything. Still replace?

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Also I do not really see where you think someone used rtv at some point. I see the orange seal. But are you talking about the black stuff along the edge that is cracking?

 

[19Eclipse90]

See I think I disagree on this one guys. But correct me if I am wrong. In order for the coolant and oil to mix the cooler would have to have been overtightened and crushed and would need to be replaced. The coolant fins would have to be damaged for them to mix. They are sealed from each other internally. That rubber seal is only to prevent an oil leak from where the cooler meets the housing. The paper gasket would not cause it either. That is only for oil. The center stud has come loose on almost every DSM I have owned and yeah it leaks oil but does not mix.

This is what I thought as well. It's been a hot minute since I've actually looked at one but it makes perfect sense and falls in line with what I seem to remember.

 

[AWD-Tony]

I agree with Jakk220. The cooler is just that, a cooler and shouldn’t leak unless it’s damaged, no gaskets to replace on it for coolant, and the seal on the cooler is just for engine oil between the cooler and the ofh, nothing else.

 

[pauleyman]

I will conceed. I still think the op needs to rule out all suspects, including the cooler, before jumping to head gasket. Simple quick leakdown and coolant pressure tests will likely reveal the issue