I really like this car, but lately she has been fighting me "tooth and nail" with an oil seep/leak located behind the S/C / alternator bracket. About six weeks ago I completed a head gasket removal and replacement with no issues. The car has run great, better response and best of all no coolant weep on the back of the head (I suggest an OEM head gasket, I believe it is made by Victor Reinz). I replaced all of the pulleys, tensioners, water pump, belts, hoses, exhaust manifold gasket, SC gaskets, etc. Pretty much everything that you can replace during the process.
Back to the oil seep. What I had thought was an oil weep coming past the threads of the long mount bolt (right, lower) of the bracket, was actually coming from the timing chain cover next to the bolt. This is a compound curve and is probably the most likely area for a leak to start. It must have been an issue for a long time, but did not become a big issue until after I had replaced the HG. The engine side of the bracket was dirty and coated with old oil and dirt. When everything is tight at the head, a small leak at this area will become exacerbated.
The first time I attempted to repair the leak the bolt in question had oil on the threads where it goes into the engine block. Great, I thought I had found the problem. I wet prepped and reinstalled all of the hardware and reassembled. No good. After 3 times of pulling everything off of the right side of the engine I was ready to pull my hair out! In my mind I was fixated that the mount bolt was leaking, but it was the corner of the timing chain cover next to the bolt. Over time, the oil leak migrated along the bolt threads. I am really good at removing components now and can get to this area in about an hour. I still wish I only had to do it once!
I used a fuel tank sealant that works great for jobs like this. It's 8802 B1/2 that has a 24 hour full cure time. It is pliable after a full cure and when the surface is prepped clean, will stick like no ones business! I also noticed that the cast aluminum bracket has some very sharp edges at the feed through holes where it mounts to the engine block. File the sharp edges where it mounts at the block for a better fit. The MB castings for this model are not the finest.
I now have a clean and dry underbelly with no signs of oil leaks (as it should be!). My wife thinks I am a nut case for repeatedly going back to address the issue! It did take some time to diagnose and fix, but it's done now! Just remember, if you fix one issue like the head gasket, it may affect other areas such as this! I have decided to change the name of my car from "Argento" to "Amante Geloso", the "Jealous Mistress". I hope this helps some other members with similar issues. Ciao!