It is hard for my very small mind to come to grips with how nasty/pesky of a leak this can be. And was......
The seal wasn't deteriorated or mushy at all, it just didn't keep the tube from leaking. If the wagon was parked in the same spot for 2-4 hours, it would leave a spot about the diameter of a baseball to softball.
I don't remember who it was that posted a pic of their tube a month or two back, but the "ultra copper" looked like a good bet.
I sprayed the area off at the carwash on the way home and parked the wagon on ramps yesterday. I then used brake/carb cleaner on the area, and doused it with alcohol. Wiped it down and liberally applied the ultra copper RTV and let it sit overnight.
Well today I was parked in the same spot for around 6 hours, and did not even have a drip!! Not one! We will see how long this holds.
Now I need to replace the gasket between the oil filter housing and the block on the 240. Nasty.......

FYI, the pics are after a full day of driving.

Attached Thumbnails

       

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Try tightening the bolts on the oil filter housing before replacing the gasket. I fixed a bad leak once by simply torqing the bolts.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

That's one ugly-looking repair. I don't think RTV will hold up forever for that task, as it is supposed to fill gaps rather than make a blob. But here's to the hope that it works for a long while.

I would try JB Weld. It'll hold anything together, the vibrations of a diesel may loosen the RTV that you applied.

__________________
Closing the store
Benzbonz.biz on your smart phone or tablet.

Here is what I was looking for.....

http://www.peachparts.com/shopforum/showpost.php?p=1408680&postcount=31

Here is the quote I am hopeful of......
"I did this over 1.5 years ago, hasn't leaked a drop since!"

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Would replacing the seal itself solve this problem? You said you still had a leak, even though the seal appeared to be in good condition, so it kinda sounds like a new seal wouldn't make things better. Both the SD and D have leaks in the same location.

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.

In my experience that seal hardens up and causes a leak. It's not too hard to replace it. I did a short write up on the procedure in a diffrent thread.

__________________
1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

I replaced my seals about 5 years ago and it hasnt leaked since. At least not there. It would be a pita to do on the ground. I had a hoist.