E280CDI SPORTS ESTATE and C200 KOMPRESSOR SE Coupe Auto (1.8 lit petrol)
I certainly would not be spending serious money on sealant for a diff drain plug.
I've changed diff lube on a number of vehicles and never used anything special.
- - - Low temperature - low pressure - Why would you ?
Any oil resistant thread sealant should be OK.
I've used a few wraps of PTFE tape in the past.
I've never had any leaks on the E300TD or any of the other vehicles that I've done a diff-lube change.
The only MB that I've ever done a diff oil change on was a 1997 E300TD.
That was at 200,000 miles ... The car died in an accident at 230,000 miles
I've had one W126, three W210s - all with 200,000+ on the clock.
None of the diffs have ever given trouble - Two E300TDs wrecked in accidents, and the W126 and the E430 that I sold on ...
I now have the W211 E280 (182,000 miles) and the W203 C200 (95,000 miles).
Changing the diff lube is well down my list of priorities.
Engine oil and ATF ..... YES - Critically important ... And many owners neglect these and get away with it.
The only times I've ever taken the diff cover off were:
- a 1974 Chevy Impala 350 ... Removed to release an axle shaft
- a Bedford CF van ... Removed to do a complete diff rebuild.
For both of these I used instant gasket when replacing the diff cover.