200tdi Rear crank seal problems!

Hi all. I'm having a nightmare with a leaking rear crank seal on my 200tdi.

I have completely rebuilt the engine from a bare block with new rings seals, bearings and shells. I used a genuine seal (the metal one with the green on it) when I first fitted the flywheel plate during the rebuild. Used the plastic guide and the method stated in the workshop manual but it started leaking pretty much straight away when I took it for its first drive. Thought that's a f*****er I must have damaged it when fitting and resigned myself to taking the engine back out to change it. Fitted another new genuine one, cleaned up/ checked the seal face on the crank and refitted the engine. This started leaking pretty much straight away too.

It is defiantly leaking from the crank seal and not the gasket between the block and flywheel plate or the the sump or ladder frame.


Has anyone else had this problem and found the leak on the seal to be caused by something else? I've been reading up a bit and seen it mentioned that if there is excessive crank case pressure this can cause the rear main to leak.

Any advise or suggestions needed before I fit another new seal and refit the engine hoping for the best.

Thanks in advance

I know it my sound silly but is the surface the seal runs on damaged ? I has similar on a transfer box the shaft had a slight nick in it

Foxyred said:

I know it my sound silly but is the surface the seal runs on damaged ? I has similar on a transfer box the shaft had a slight nick in it

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Yea it looks in good condition. Was a bit glazed when I took the first seal off but I cleaned it up with some fine scotchbright before fitting the second seal. I even checked the run-out of the crank with a dti to make sure it's running true which it is.

I assume you fit the seal dry like on the 300 (don't lubricate the crank journal it runs on)?

Kwakerman said:

I assume you fit the seal dry like on the 300 (don't lubricate the crank journal it runs on)?

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I didn't put oil on it but the crank may have had a touch of oil left on it from the leak.
Is that a big no no oiling the seal?

Don't know about the 200 but on the 300 it seems to be a no-no, not sure how much oil is actually needed before issues occur.

From the 300, slightly different seal arrangement but same principles may apply?

Ah that Deffo says to keep it dry! Doesn't say anything about being that careful in the 200tdi manual. Maybe that's where I went wrong!

Dry baby dry!
My last one came loose and spun in the flywheel housing, new seal and good old loctite has kept it dry ever since and that is on a well worn 200 with 20/50 oil to keep the oil light off at idle and it breaths like a pig when worked hard.