Rear crank seal still leaking

[Varsas]

Hi.

I've just put a new engine in my S3, just a standard 2.25 3MB diesel. I'm pretty happy, it runs well with no smoke and does 48mph on the flat, and I haven't finished setting the timing yet.

Unfortunately, despite fitting a new one before fitting the engine the rear crank oil seal appears to be leaking fairly badly (plenty of oil from the wading plug, doesn't smell like gearbox oil to me, and it didn't leak before)

I obviously did something wrong when fitting the oil seal, so before I take the engine back out to change it does anyone have any advice for me? I followed the ROM and the haynes manual.

Could someone point me toward the correct jointing compound and silicone grease, so that I know I am using the right stuff?

I put the grease inside the seal (where it runs on the crank) and the jointing compound on the outside, and where the 2 halves of the seal meet. Is that correct? Is anyone able to describe in a bit more detail what goes where?

One line in the ROM did confuse me. It said something about locating the seal in the approximate running position on the crank (this position is important) but surely the seal just goes up against the back of the rear main bearing, it can't go anywhere else can it? What do they mean by this?

I did ensure I used the correct, genuine LR part (well, I thought it was...having second thoughts now!) Is it possible the crank is worn and that's why it's leaking oil? I did measure the crank when the engine was out and it was sort of OK (just about inside tolerance) but I didn't measure that part of it (I assumed it wouldn't be worn).

Cheers in advance for the help!

[Varsas]

I have got some input on this from a local specialist, I'll post it here in case it'll help anyone else.

They have a kit that's different to what was used before (as stated in the parts catalogue, the 'rear crank oil seal assembly' should have silicone grease with it; this kit also has instructions with it, hopefully not just a re-print of the ROM). I'm also taking their advice re: the rest of the potions the ROM mentions so hopefully it'll be better this time round...

It will be very annoying if it turns out it's leaking because of a poor quality seal, especially since I thought I was buying a genuine part.

[Daan]

Did the crank have a groove were the seal runs? Usualy if the sealing surface is worn this way, the new seal will wear out very soon. You can have it reground if needed, but its crank out of the engine then. I have done this seal in the past, and from memory, it is a split seal, which have to bend out to fit over the crank. A bad construction to be honest, I was advised at the time to heat the seal up in boling water, to make the splitting the seal open easier and less likely to create tears in the rubber. Another thing: there are 2 cork seals on bith sides of the bearing cap, which are almost guarenteed to leak at some point. I was advised to not use these but fill up the voids with dow corning sealant and be done with it. It has worked, and my s3 was leak free for some time....

Daan

[Varsas]

Thanks for the reply.

Yes, Land Rover changed the design in circa 1980, so it must have been bad!

I did not notice a groove in the crank, so either I didn't see it or it's not there, either way could well be my problem...I really hope I don't have to have any work done on the crank; I've already spent quite a lot of money on this engine!

Thanks for the tip re: softening the crank, as for the T seals I'll make sure I cover them in gasket sealant when I re-do them.

[Snagger]

Did the crank have a groove were the seal runs? Usualy if the sealing surface is worn this way, the new seal will wear out very soon. You can have it reground if needed, but its crank out of the engine then. I have done this seal in the past, and from memory, it is a split seal, which have to bend out to fit over the crank. A bad construction to be honest, I was advised at the time to heat the seal up in boling water, to make the splitting the seal open easier and less likely to create tears in the rubber. Another thing: there are 2 cork seals on bith sides of the bearing cap, which are almost guarenteed to leak at some point. I was advised to not use these but fill up the voids with dow corning sealant and be done with it. It has worked, and my s3 was leak free for some time....

Daan

The aft main bearing cap "T seals" can be a problem, and RTV sealant is a good alternative. T seal failure could look like crank seal failure.

Did you use a good brand seal? Britpart seals are like colanders. Use genuine parts for bits like this.

[Varsas]

The aft main bearing cap "T seals" can be a problem, and RTV sealant is a good alternative. T seal failure could look like crank seal failure.

Did you use a good brand seal? Britpart seals are like colanders. Use genuine parts for bits like this.

Cheers, I will check the T seals.

I *thought* I had used a genuine part (I did actually order two after I realised the first was a pattern part) but it didn't come with the silicone grease (like it's supposed to) so I guess it wasn't. I have been assured the one I am picking up today is genuine.

[Varsas]

Just to update for anyone else having these issues.

I have now replaced the rear crank oil seal (what else are bank holidays for?) and it appears that one of the 'T' seals were not sealing. One seal was soaked with oil, so I presume it was letting by. As far as I could see the seal itself was OK, i changed it anyway. As an aside the T seals supplied with the genuine land rover kit (the box even said genuine Land Rover parts on the box) were noticably thicker then the old ones, so thick that I couldn't actually get them to fit even when lubricated with silicone grease as per instructions. Instead I did as suggested and filled the void with RTV sealent, I just filled the voids...then blocked up the holes at the bottom as I fitted the main bearing cap, which should do it!

I then very carefully followed the instructions and tips as per above when refitting the new seal. The instructions also did make a bit more sense this time, I didn't really understand how it was supposed to go together before, I do now.

It seems to be OK now, following a 20min engine run, then short test drive, another 20min engine run (after letting it cool) and a 20mile drive it seems to be dry...I really hope it'll stay that way this time!

Once again, thanks for the help.