I've been tracking down a small oil leak (only a drop or two on the drive) which may have got slightly worse recently. After using half the world's supply of brake cleaned to clean the mess off the engine, gearbox and transfer box, I drove it around for a while and the only area of leak was out of the hole at the bottom of the bell housing. It's a TD5 auto.

So I removed the small inspection plate that is held on with 3 bolts (it was dry) and looked in. All the autobox area is dry, but there is oil on the "sump" which could have come from the crankshaft seal somewhere above. The leak is definitely engine oil.

I may have not looked properly, but there doesn't seem to be many reports of the rear seal leaking. I guess it could be the sump gasket just in this area leaking, there are no records of the sump having been removed in the past, but the cross-member has one bolt missing which is suspicious maybe.

Is a leaking rear seal common? If it is the seal, do seal conditioner additives work without damaging other parts, so are they worth a try? It has done 153k miles by the way.

The leak is not too bad at the moment, but it won't cure itself!

Thanks.

Could it be coming from the back of the head? There's a seal under the rocker cover that can leak. Is there a round camshaft seal at the back too, like there is at the front of the head?

There are plenty of places, especially lhs of engine, which could blow back.

Spong said:

Could it be coming from the back of the head? There's a seal under the rocker cover that can leak. Is there a round camshaft seal at the back too, like there is at the front of the head?

Click to expand...

Thanks. I was dreading finding the blanking plug leaking, but all that area including the rocker cover is completely dry. I did have the front blanking plug leak some time ago which is what made a load of mess at the front of the engine which was blown back, but that is all dry and clean now too,

Bantam1 said:

There are plenty of places, especially lhs of engine, which could blow back.

Click to expand...

Thanks. Since my massive de-grease, the engine is clean and dry apart from the few drips out of the bell housing. The front cam blanking plug did leak which made a real mess of the engine, but all cleaned now.