Thread: Persistent Sump Leak

Are you sure that it is the sump gasket? I have also a '97 300Tdi and it exhibits the same little problem oil leak, and believe it or not that is the sole indication of an oil leak anywhere beneath the car at 180,000 kls. The oil was slightly smearing on the right side of the sump and a little bit on the front diff/driveshaft. I thought sump gasket, until the last oil change, when I climbed under the car with the engine running to check the filter joint, I looked up and saw a small amount of oil being spattered out of a joint on the brake booster vacuum pump on the right side of the engine block. There is a riveted joint there and as the parts appear to be plastic it looks like the rivets have loosened allowing a small amount of oil to constantly escape while the engine is running and pump operating. The brakes are fine, as a matter of fact much better than my previous Disco. How to fix the leak at the pump............I will have to look in the forum. Hope this may help. Cheers.

Probably the rear main seal and/or the T seals leaking. Either engine or gearbox out to repair.

Thanks, good suggestion and I wish that was the problem. Unfortunately, I've already done the 'upgrade' on the vacuum pump (rivets replaced with nut & bolts, new gaskets) and that's one component that _isn't_ leaking! Worth doing the fix on the pump too; I found I had improved pedal feel and bite under heavy braking afterward, rather than the wooden feel it had before.

Thanks for the suggestions guys. I've done the 'upgrade' on the vacuum pump (rivets replaced with nuts and bolts, new gaskets) and I'm certain that is one component that _isn't_ leaking. BTW gazby, I'd recommend carrying out this straightforward fix; I found that it improved both pedal feel and bite under heavy braking on my Disco.

It shouldn't be the real main seal either, since I paid to have that replaced when the clutch was done about 20K km ago - guess that doesn't guarantee anything. Not sure about the TC though. If it were the TC, would the oil leak down the outside of the bellhousing and / or inside the BH and out through the breather hole? If it were the latter, perhaps I could put the wading plug in, clean up the oil, then see if I get a leak?

When Mr BJ say t-seals he isn't referring to the transfer, but the seals on the #5 main bearing cap - they are a T in shape- and they get hard and let oil run down between the engine block and transmission adaptor. They wouldn't have been changed when the clutch was done. However, I dissent with Mr BJ as to how to repair it: Sway bar down, sump off, cap off and new t-seals. There have been a few threads - search for "300tdi t-seals". It's reasonably easy.

Hi eeyore,
I had similar problem, you are best washing off the sump as best you can with a degreaser and then watching where it comes from. I used the Toyota black sealant, seal packing (Black) it is called, part number 00826-00080-A. I'm not a great fan of the Yotas, but this stuff is second to none, and it ain't $68 a tube. Since putting the sump back on it has been as dry as a bone. One thing with the Yota sealant is it has to be assembled within five minutes of application which means to have to be well organised.
Hope this helps.

Ah, didn't read Mr BJ's post properly. Just saw main seal and 't' and jumped to the wrong conclusion. Thanks for clarifying that langy. Your description of the leak point pretty much exactly matches where I think the oil is coming from too. I'll do a search as you suggest.

Since I'll have the sump off anyway, I'll take your advice too Nomad9 and try some of the Toyota sealant - should have all my bases covered then

Thanks to all for your help.

In case you're not already doing it, give the sump and block faces a good wipe over with thinners before you put the sealant on too.

Steve