Series 3 Sump seal leaking

The sump seal on my Series 3 2 1/4 Diesel that I rebuilt started dripping quite badly at one corner today.

I noticed this when I pulled into a petrol station to fill up. By the time I got back out of the shop there were a couple of golf ball sized patches underneath it.

This is especially annoying as it is a professionally rebuilt engine.

Is nipping the bolts up at the leaking corner worth trying, or will it mean taking the sump off and re-doing the entire seal.

Thanks for any replies.

Might ultimately need removing and resealing but I managed to stop mine leaking by nipping them up evenly. To be fair they were a little slack. Don't over tighten and distort the sump flange though

The sump is the most uneven lump of scrap you are likely to see. I dont know why they bother machining the face on the block they are that bad. There are several gaskets you can get ranging from toilet paper thin to a good couple of mm. Obviously the thick ones have more chance of sealing the uneven gaps. I have been told spreading gallons of blue instant crap all over it helps but I dont.
The front of the sump flange also seals the timing chain cover and the extra work it has to do around this area can only be bad news in reality but a seal can be achieved.
This was one of my little gripes when I did mine.

Thanks for the replies. I will try nipping the bolts up first.

It seemed fine for the first few months, but suddenly leaks now.

i had what i thought to be the same problem but after three atempts and gaskets i found it to be the crankshaft oil seal,

If it is a three bearing it is only a matter of time and luck as to how long the rear main seal lasts. Minor leaks from the rest of the sump won't bother you then. Best I have had from a rear seal is 18 months or around 15000 miles. Iv'e tried three times to cure the rear seal leak and all have failed after a longish 50 mph motorway cruise.

think that's what my leak must be seems to come from the back of the engine somewhere, never tried to do anything about it though - assume its a big job - i just put up with it

rear main bear cap ,where it joins block and sump is prone to leak, plenty of rtv silicone sealant along the joints helps as well as sealing housing to block around the cap area

divie said:

If it is a three bearing it is only a matter of time and luck as to how long the rear main seal lasts. Minor leaks from the rest of the sump won't bother you then. Best I have had from a rear seal is 18 months or around 15000 miles. Iv'e tried three times to cure the rear seal leak and all have failed after a longish 50 mph motorway cruise.

Click to expand...

It is a three bearing. At the moment, the leak is definitely coming from the sump itself.

Why are the seals so prone to failure on the three bearing engines?

Why are the three bearing rear seals prone to failure ? Well the are a bugger to fit, unlike most engines they are a split seal and are not slid on to the crank but sort of wrapped around it and sit in a groove. Couple this to TEE shaped cork or rubber side seals in the main bearing cap the design leaves a little to be desired. We must remember this is a throw back to the pre war Rover P3 engine design, in that era rope or felt seals where the norm. I rebuild pre war motorcycle engines and have all sorts of sizes of "wad punches" to make the seals. Even BMC "A" series engines used felt seals. Technology moves on, we do not expect a modern engine to leak but if you get chance take a look at a Landie three bearing crank if it is well used it will have a groove worn where the seal runs and by design can not be sleeved to improve it.

Thanks for the reply.

As it happens I found out today that the leak is not the sump at all, but the small diameter metal pipe that runs from the back of the head to the block.

The pipe itself has a split about an inch up from the bottom banjo fitting. The oil is dripping from there.

Can anyone tell me the correct name for this pipe so I can order a new one?

Sounds like the cylinder head oil feed, 275679

Thanks, that looks like it.