Oil seeping from turbo oil return line at engine

[BobG999999]

Last thing and this car is ready to go.

I've replaced the gasket twice now. It's on the turbo oil return line where it bolts to the block.

I'm talking about this gasket: https://parts.vw.com/p/Volkswagen__T...6F145757L.html

Is there a "right" way and a "wrong" way to put that on? I've put it on with those little tabs pointing away from the block and snugged up against the flange on the hose.

Help! It just won't stop leaking oil.

[Smac770]

Fairly certain the tabs are meant to hug the end of the pipe, not press against the block (ie, sounds like you put in on correctly). The torque spec for the two bolts is only 9 Nm. That's more than hand screwdriver tight, but not that much for a wrench.

Is it possible the mating face for the pipe is not flat? Take it off and use a flat edge to confirm it's flat.

Are you sure it's the seal to the block, and not maybe a leak in the pipe itself running down? Maybe close one end and pressure the other with a hand pressure pump/gauge to 40 or 50 psi (3-3.5 bar) and see if it holds.

The correct bolts are M6x15; check they are 6mm diameter and 15mm long (shank length, without the bolt head). https://www.ecstuning.com/b-genuine-...n10619201~oev/ Honestly, I don't know if the washer gets included in the bolt "length" or not.

[BobG999999]

Yes, that's how I put the gasket on. I was looking at the one that came off, and noticed that around the center opening, the two sides are not flat. That's what made me wonder if there was a right or wrong way to put it on.

Unless I take the other end of the hose off (don't even know if I can get to it), I can't move the hose enough to check the flange surface. The mating surface on the block looks flat, but there's not enough give in the short piece of rubber hose to let the it flex enough to turn it down so I can see it. I'm using the bolts that were on it originally, so unless Audi saw fit to use TTY bolts on this little application (I sure hope not), I should be able to re-use them.

[Smac770]

The bolts are not replace if removed; safe to reuse. No idea then. The one time I've messed with it, when I replaced my turbo, I didn't have any complications with it leaking. So not sure what it might be if there's nothing obvious.

[MongoMcG]

There might be more luck in getting that hose to flip up and toward the rear to get a look at the block. Those three lines are really jammed in there, and you don't want to mess up that short oil return line (Audi part # 06H145735G) - it's over $180(!) at the time of this writing. It has an unserviceable filter built into it that can get clogged.

Per Smac and the Audi service manual, the seal is indicated as 'replace', but the bolts are not. Torque to 9Nm (80 in lbs). If re-using bolts give them an extra bit of turn depending on original torque spec (for 9Nm I add about an eighth of a turn). If you want to replace the bolts, I believe they are M6 (pan head/triple square) x 15mm with a captured washer, Audi part #N10619201, but check with an Audi part department to verify.

If the seal is new and the bolts are torqued to spec on an unbent hose flange, and if you are still experiencing a leak, I suspect the leak is not at the connection to the block, but in the hose assembly.

[BobG999999]

Wanted to give an update.

I noticed that the gaskets were not flat. There was a slight raised area around the opening. We flipped it over so the tabs were on the top, against the engine block. That seems to have solved the problem!

[A4x]

Worst case you could put a light bead of Permatex Copper RTV around the gasket, should help seal it for good. Just don't put too much which could get inside and block the oil flow.

[BobG999999]

A4x ... that's basically what we ended up doing. Put a bead on both sides of the metal gasket, spent 30 minutes putting that bitch into place, and finally, no leaks!

Thanks to all for their suggestions.