Oil cooler question (NOT THE O-RING)

[StriktlyAudi333]

A4 B6 AMB 1.8t

Hey guys,
Just a quick question in the hope to find a similar experience that someone else had.
I've got a misfire on cylinder 3 that occasionally happens on cold starts and is the only piston with a wet top.
- "replace the head gasket"
- not my problem
When I pulled the oil filter and was looking through the oil cooler to determine the culprit, there was a slow leak of coolant from the 27mm bolt. Is there a washer underneath and has anyone's leaked from here before? I want to just put some force on the bolt to tighten it a little am not sure if it's a good idea or not and what the torc is on it. And it's not a big enough leak to cause oil/coolant mixing because, I'm assuming, it just gets burned through and once that's done gettin blown out, my misfire isn't there.

-can I put force on the bolt to push it more on the washer for a simple fix?



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[Seerlah]

What 27mm bolt?

Coolant is to be contained inside of the oil cooler. It is never supposed to pass out. It has an inlet and an outlet. Other than that, coolant stays contained inside it. If you have coolant coming into the oil side, that cooler need to be replaced. The gasket between the oil cooler housing adapter and actual oil cooler is to keep the oil contained as it moves from adapter housing (part bolted to block) to cooler.

Oil enters through npt pipe threaded on each side, from adapter housing into filter. One side threaded into the adapter housing, and the other end your oil filter is threaded onto with your oil cooler in between with a straight passage for the threaded pipe. There is a locking nut that keeps the oil cooler housing and oil cooler sandwiched together, with a rubber o ring in between. After oil passes through the middle of the filter, it comes out the sides and through the oil cooler back into a separate section of the adapter housing. From there, your cooled and filtered oil gets distributed through the block via pressure from your oil pump.

No coolant should ever leave that cooler. If you have coolant there, the cooler itself needs replacement.

Edit: Just thought about what you really wrote. Your situation seems weird. Not quite sure what is going on, but I forgot how you mentioned the cylinder 3 issue. I was only thinking about the coolant by your filter. Have to think about this some more.

[StriktlyAudi333]

Thank you so much for the reply I appreciate the education of that! It's extremely weird and is driving me nuts. Oil for certain is not getting contaminated by coolant according to the dip stick anyway. Coolant is getting lost though but very slow. I temporarily put an extremely thin oil in hoping the leak would worsen so I can better see what's going on. I'm gunna take a picture here in a little after I drain the oil out to put my normal stuff in. But it's that nut you mentioned that is threaded in between the cooler housing, and the filter. It's a slow, very slow, leak from behind it making it seam like the liquid would have to be running down the thread that it's tightened on. What would that liquid be? It seams to be coolant but may not be? But basically, with it running down the threads after getting past the nut, it's entering the oil filter. I'll get you some pics here in a few when I start it.


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[StriktlyAudi333]

Oh and my misfire is only on cold starts, and lasts for about 10 seconds


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[StriktlyAudi333]

What 27mm bolt?

Coolant is to be contained inside of the oil cooler. It is never supposed to pass out. It has an inlet and an outlet. Other than that, coolant stays contained inside it. If you have coolant coming into the oil side, that cooler need to be replaced. The gasket between the oil cooler housing adapter and actual oil cooler is to keep the oil contained as it moves from adapter housing (part bolted to block) to cooler.

Oil enters through npt pipe threaded on each side, from adapter housing into filter. One side threaded into the adapter housing, and the other end your oil filter is threaded onto with your oil cooler in between with a straight passage for the threaded pipe. There is a locking nut that keeps the oil cooler housing and oil cooler sandwiched together, with a rubber o ring in between. After oil passes through the middle of the filter, it comes out the sides and through the oil cooler back into a separate section of the adapter housing. From there, your cooled and filtered oil gets distributed through the block via pressure from your oil pump.

No coolant should ever leave that cooler. If you have coolant there, the cooler itself needs replacement.

Edit: Just thought about what you really wrote. Your situation seems weird. Not quite sure what is going on, but I forgot how you mentioned the cylinder 3 issue. I was only thinking about the coolant by your filter. Have to think about this some more.

Okay so I kinda feel stupid but I still think something is wrong. Here's some pics but I drained my oil, pulled the filter and the oil feed line in the cooler won't stop. Plug is still out and cap is off and my coolant is drained too. This has been dripping out for a solid 20 min steadily