1989 740T: It appears I have sprung an oil leak from the oil cooler adaptor thermostat adapter. The oil is not coming from the adaptor to block gasket (I just replaced that), and I can't see any other place in there that it could be.
So, if I'm right, the question is: can I replace the gasket- I have it- a green O ring- on the car?
It looks to me that I can remove the oil filter, then the two pipes to the oil causing the leak. I read through the FAQ, but I can't find a picture of the assembly

Be sure to counterhold the hardline adapter fitings securely, they seem to like to stick. I removed one in car, and it was easy after I cut the hard lines. Installation on my diesel was not too hard, but i had the sway bar and steering rack out when i did it.

The adapter on my car was porous. I went nuts tightening the fittings, then replacing the copper washers--then I saw the oil actually oozing through numerous tiny cracks in the adapter itself.

I am assuming that the thermo housing gasket is the culprit. I am going to get some dye and trace it today, after I wash off the mess. My concern is that the leak appeared after I did an exhaust manifold gasket R&R job, and that I may have damaged something in there that I can't see. I doubt mine is porous, but thanks for the input, anyway. I am still open for ideas, though.

R

Does anyone know the torque for the bolt that holds the thermostat housing to the adapter?

Thanks in advance

Rick

Not a direct answer for your torque value quest, but as its job is to squeeze the o-ring between the block and tstat, I figure it is properly tightened when it stops movement toward the block plus a slight bit more to create tension.

The o-ring doesn't last 20 years. I can say that much for sure. As for some pics, I'll post these without qualification, 'cuz I gotta run.

Great! This is the first view of the unit I've seen. The manual just glosses over the adaptor assembly. The view you show is the side opposite the oil filter?

R

Rick,

The side with the 0-ring groove is against the block. The other side is smooth for the oil filter seal.

Now, reading again, I'm not sure I answered your torque question at all. Where is the leak you are trying to fix? At the pipe connections, from the spring tensioner plug, or between the block and adapter? I remember a steel washer over the adapter extension pipe nipple, under the retaining nut that was, I think 1-1/8" on the flats, as I loosely used an old 30mm axle nut socket. That thin steel washer, I thought, was just to keep the nut from chewing up the die cast metal of the adapter housing.
--
Art Benstein near Baltimore

Thanks- I got up early Monday and got the washer from Volvo. The first leak was between the oil cooler adapter, between the block and the unit, then the next one was between the unit and the banjo bolt that holds it onto the block. The washer is def. a seal, now that i see it. it's soft aluminum and looks designed to crush a bit to make the seal.

Rick