2.0T engine coolant mixing the oil in a few minutes idle run

[seppok]

Hello,

I have a problem with my 2008 A4 2.0T engine. After a few minutes idle oil is getting "milky" and coolant tank is empty. Thought it's a head gasket and replaced that one. No help. Then start thinking it's a cracked head. Went to a scrapyard and got a head out of other 2.0T engine.
Bolt everything back together and started it once again. And after a few minutes dipstick was "milky" again and tank was almost empty.
Kind of hard to believe it's an engine block what is cracked because it's cast iron, not aluminum. Can it be a bad turbo or is there an oil cooler somewhere which
could cause this problem?

[IbisB7stage2]

there is an oil cooler that transfers heat to the coolant. near the oil filter, above it. much more likely to fail than head gaskets, these cars dont blow head gaskets.

[seppok]

So can't be turbo or cracked engine block?

[Jayz691]

So can't be turbo or cracked engine block?

Anything is "possibele", bit oil filter housing/oil cooler is much more likely. Cuz its a very common issue. These things don't really blow head gaskets, and if it wasn't overheated, doubt the head is cracked. Start with the simple, cheap parts always.

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[MorAudiProblems]

If it's not the coolant/oil filter housing I would try this next.

assuming your coolant is dumping to the oil...when you drain the oil is a there a lot more than should be in there? like oil quantity + coolant is quite a bit of fluid. if not, your coolant is burning up. I would clean the fluids and refill. pressurize the coolant system and see if the pressure drops. Then without starting it look in your cylinder through the spark plugs hole and see if there is fluid(read coolant). If no pressure drop and no fluid in cylinders. Do a leak down and hold the pressure for like 45 minutes per cylinder. if it's not the head gasket, it's cracked walls. keep en eye out for bubbles in the coolant reservoir, also note pressure drop per cylinder.

another funny place just to check is the coolant runs to the turbo and back to the block. make sure you don't have a oil return line and coolant line switched up.

These are all the places I can think of things getting switched up.

[seppok]

Yes there is a lot of water mixed with oil after a few minutes idle run. Just wondering is it even possible to swap turbo's coolant and oil lines. One coolant line runs in front of the engine but newer looked where other end goes.

[seppok]

I think it's not possible to get those hoses swapped. Those hoses are tied together so way to mess up those ones.

[MorAudiProblems]

I think it's not possible to get those hoses swapped. Those hoses are tied together so way to mess up those ones.

you are right, it's not likely those are swapped. Did you check your oil filter housing/oil cooler?

[Theiceman]

I'd bet it's the oil filter housing. Quite a few failing lately with this symptom. It's not really the cooler. It's a massive corruption of the plastic in the oil filter housing

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[seppok]

Will get a new housing today. I will update the results later but I really hope that fix this problem...

[seppok]

Looks oil filter housing did it! Probably that old plastic was failing and cracked inside. Why they are using plastic with critical engine parts????

[tractoman]

Hope you put an oem part on. Aftermarket are prone to early failure.

[Theiceman]

Looks oil filter housing did it! Probably that old plastic was failing and cracked inside. Why they are using plastic with critical engine parts????

You can usually see the broken section when looking at the housing once you take it off ( inside).
If this is the first plastic you have had fail you better strap yourself in.
Stat, coolant flange, Intake flap, valve cover, PCV,

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[IbisB7stage2]

Stat, coolant flange, Intake flap, valve cover, PCV,

I sung that to the tune of "head shoulders knees and toes". its catchy

[deusilan]

Going to jack this thread since it refers to the same issues I have but my car is an 05.5 with 302k miles. Recently my oil filter housing came off the block and leaked everything out. I didn't have time to deal with it so I gave it to my buddy. He told me the previous mechanic used silicone on the oil filter housing to hold it on, which also leads me to question if they actually changed it or just threw some flex seal on it. My buddy kept the same oil filter housing but replaced both gaskets and cleaned up the area. That put my car back on the road, for a few months.
Flash forward to today, the car has been drivable but I've been slowly loosing coolant. Coolant flange is good as there's no dry coolant on my tranny and all of the other hoses and water pump look good & intact. My only culprits left are bad oil cooler, oil filter housing or cracked head gasket. I'm leaning towards the former because I don't get oil in my coolant tank and the car still boosts properly, although when I was pushing it that's when I noticed my coolant went down to almost nothing lol. Cracked head gaskets usually put out white smoke from the exhaust as well (correct me if I'm wrong here). Just spitballing here and looking for some opinions.
TIA

[K1196A]

Going to jack this thread since it refers to the same issues I have but my car is an 05.5 with 302k miles. Recently my oil filter housing came off the block and leaked everything out. I didn't have time to deal with it so I gave it to my buddy. He told me the previous mechanic used silicone on the oil filter housing to hold it on, which also leads me to question if they actually changed it or just threw some flex seal on it. My buddy kept the same oil filter housing but replaced both gaskets and cleaned up the area. That put my car back on the road, for a few months.
Flash forward to today, the car has been drivable but I've been slowly loosing coolant. Coolant flange is good as there's no dry coolant on my tranny and all of the other hoses and water pump look good & intact. My only culprits left are bad oil cooler, oil filter housing or cracked head gasket. I'm leaning towards the former because I don't get oil in my coolant tank and the car still boosts properly, although when I was pushing it that's when I noticed my coolant went down to almost nothing lol. Cracked head gaskets usually put out white smoke from the exhaust as well (correct me if I'm wrong here). Just spitballing here and looking for some opinions.
TIA

I'll say that when I had a leaking oil cooler I pulled it and just did the gasket and shortly they're after I had the same problem again. I had read that the cooler itself warps sometimes so I replaced the cooler and gasket and the problem went away. Apparently it's a semi well-known thing that the cooler should just be done instead of bothering just trying to do the gasket. Not sure if that's your issue but I hope it helps you give something to look at or to rule out. I bought my oil cooler from FCP because they have the lifetime replacement warranty and that way I'm at least covered part-wise if I have to do it again.

Good luck!

[deusilan]

I'll say that when I had a leaking oil cooler I pulled it and just did the gasket and shortly they're after I had the same problem again. I had read that the cooler itself warps sometimes so I replaced the cooler and gasket and the problem went away. Apparently it's a semi well-known thing that the cooler should just be done instead of bothering just trying to do the gasket. Not sure if that's your issue but I hope it helps you give something to look at or to rule out. I bought my oil cooler from FCP because they have the lifetime replacement warranty and that way I'm at least covered part-wise if I have to do it again.

Good luck!

I've only read that the oil filter housing has that issue but not the oil cooler. I would like to go with a custom oil cooler but I need to solve the issue first before splurging on a custom setup. I will have to pull everything apart and examine it but it makes sense to have the parts on hand.
Thanks.

[K1196A]

I've only read that the oil filter housing has that issue but not the oil cooler. I would like to go with a custom oil cooler but I need to solve the issue first before splurging on a custom setup. I will have to pull everything apart and examine it but it makes sense to have the parts on hand.
Thanks.

Shit... I'm an idiot. I read too fast and did not pay enough attention to detail. You're right, I'm totally thinking of the oil filter housing! I'll go bow my head in shame now.

Sorry!

[Theiceman]

Gotta figure out where coolant is going first......
Remove under body tray... That hides a lot.

If it's not leaking out, change ofh, lots of cases of this lately.
Head gaskets are solid on this car.

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[deusilan]

Gotta figure out where coolant is going first......
Remove under body tray... That hides a lot.

If it's not leaking out, change ofh, lots of cases of this lately.
Head gaskets are solid on this car.

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Its not leaking coolant and oil is not going into my coolant bottle.

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[Theiceman]

Its not leaking coolant and oil is not going into my coolant bottle.

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well this is interesting.. its either in the oil which you would see at the sump when you change it, on your dipstick, leaking out when at highway speed and not seeing it, or you are combusting it which means you would heave steam cleaned plugs....

pick your poison.