8 cylinder front engine iconic vehicle
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By Gary Knox
#149248
Do you have an oil leak on your 928?? I've owned 7 of them, and every one had at least minor leaks at the pan gasket, some more than minor! Had some replaced, replaced some myself, and they eventually seemed to have small leaks (used both OE and aftermarket gaskets) . I did a 'treatment' to my current 928 about a month ago that I would like to share, as it may be useful for others.

This car had leaks on the right side and right rear corner of the pan. I snugged up all the bolts shortly after buying the car. After driving it about 700 miles over 6 months, I found the leaks had returned, and some of the bolts had actually loosened (oil seeping into the bolt area had lubricated them enough that vibration and gravity caused them to loosen by up to about 3/4 of a turn. The car's service records indicate this gasket was replaced about 25K miles ago, and I'm not anxious to do that job. Hmmm - I had an idea.

During a private conversation with a Rennlist contributor (initials GB), I learned of an RTV 'like' material that I believe Porsche is now using in the assembly of their engines, and BMW also uses it in building motorcycle engines.. This material seems to bond very well to metal, and is apparently activated by contact with oil. It goes by two names - seemingly the same 'stuff', but two languages. In English, it is 'Three Bond', while auf Deutsche, it is Drei Bond. I used the Drei Bond, which I obtained from FCPEuro ( https://www.fcpeuro.com/Parts/?keywords=Drei%20Bond ). I doubt it is available at your local Autozone etc., but is probably available from several other specialist suppliers.

Here's what I did. One at a time I removed the 6 or 7 bolts where there was oil on the bolt head. I cleaned out the bolt holes with a bit of brake cleaner, cleaned the threads on each bolt and then put a small bead of Drei Bond on the full thread length. Then installed and snugged the bolt, When all the bolts were snug, I cleaned the block and pan outer edges where the gasket is located with brake cleaner and a brass brush, got it very clean and dry, then put a moderate bead of Drei Bond along the gasket in the area where the leakage was occurring and with my finger 'smeared' it back and forth.. About 30 minutes later I started the engine and let it run for a few minutes, then did not start or drive the car for several days.

About a week ago I drove the car about 250 miles - the first significant trip since the Drei Bond application. Highway speeds of 60-85 mph for about 3/4 of the trip, the rest was stop and go with fairly heavy city traffic. A few days after returning home I put the car on the lift and examined the oil pan. WOWEEE - every bolt and area where the leakage had been was perfectly clean and dry. I found one bolt on the left side of the pan that had about a half drop of oil on it's head (I had previously done nothing with that bolt except check it's tightness). I removed it, did the same cleaning job I'd done on the other bolts, and applied the thin bead of Drei Bond up the threads of the bolt. Re-installed and snugged it, and I now expect to have NO visible oil leakage the next time the car is on the lift.

Is it possible to have a miracle in a tube? I think so, as I now expect to have a leak free oil pan for an extended period of time. By the way, the tube is a bit expensive, but in this maintenance work I only used about 1/4 of the tube. Certainly enough left to solve quite a few more oil leaks in this or other cars.

Remember - 'your mileage may vary' - ha
Last edited by Gary Knox on Mon May 16, 2022 9:42 am, edited 1 time in total.
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By linderpat
#149420
Good info Gary. This one seems like a fairly quick and effective fix. Thanks for posting!

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