Wonders

Looks like my rear oil seal is leaking, big job right?

ItalianJoe1

Remove the inspection plugs and make sure it's coming from the rear main. These engines leak from valve covers often and it runs down the trans and looks like a rear main.

If you need the rear main seal, the transmission has to come out, so it's a big job but not really that hard if you've done that kind of work before. I did mine in a couple hours one Saturday at work. These cars are actually really easy to R&R the trans on.

Wonders

Thanks for encouragement, couple of hours wow! Have removed small inspection cover and found oil inside, should it be dry? I've looked at back of engine and can't see any leaks from valve covers, will take of air filters covers for a better look, but is probably main rear.

ItalianJoe1

That's on a lift using good tools and i'm a tech at MB, but I believe book time on the labor is around 4-5 hours so if you do that sort of work it shouldn't be an issue. Removing a trans is the same whether it's a V12 or a normal car. I actually did my catless downpipes at the same time since they had to come out to pull the trans, that took about as much time honestly.

Wonders

ItalianJoe1 was looking for leak around rear of engine but using a mirror can see fresh oil at front of engine around valve cover and oil filter housing, oil is not dripping from front of car could oil be running from front of engine to bell housing

ItalianJoe1

Yes, I've seen that happen.

Valve cover seals do leak all the time on these engines, so do them first (not that expensive or difficult), and clean it well, and see what else is leaking.

Wonders

ItalianJoe1

will i need to remove coil packs to access valve covers, expect best to remove coil packs to clean oil thats probably down there.

ItalianJoe1

Yes, you can't take the valve covers off without removing the coils.

You will usually find some oil around the plugs if the covers have been leaking, and while you're in there, if your plugs are more than 30k miles or so old, I'd suggest changing them. It's only a couple more minutes to do the plugs once the coils are out, and it's easier than doing the coil removal again later.

I did a set of valve covers a little while back on a customer car, if you do it right it can be about a 4 hour job, book time is about twice that. It's not quick or easy, but it's not complicated, just be careful and remove everything that's in the way in order so you know what layers over what when you go back together.

Wonders

Thanks ItalianJoe1, plugs were main dealer replaced in 2015, havent done 1000miles in car since then so should be okay, can you tell me what valve cover bolt torque should be, 9 or 11Nm

konigstiger

See here: http://workshop-manuals.com/mercedes...ce_and_repair/ + next page

ItalianJoe1

9 or 11 nm is so small, there's almost no difference. That's way below hand tight with a small 1/4" ratchet. Just make them tight without stripping threads.