Oil Leak

Post by **Matt** » Sun Feb 11, 2007 8:24 pm

Freemog has a major oil leak

Its got an ital 1.3 engine. The leak is at the back of the engine.

Initially there was a major leak, to the extend it wasnt dripping it was a constant stream :s We diagnosed it as the rear cork seal on the sump gasket, and the garage agreed and changed it. The leak was significantly reduced, but I still used the best part of 2 gallons driving between Southampton and London.

I reckoned the garage did a dodgy job, and re did the sump gasket again today and it still leaks

The oil appears from the back of the engine between the sump and the backplate. If you look up the gap you can see oil building up on the bearing cap. Yesterday I thought I saw the oil *spurt* out of the sump side, however the oil runs down the backplate.

Anyone got any ideas?

Post by **Welung666** » Sun Feb 11, 2007 8:31 pm

Rear crank seal? Backplate gasket?

Was the sump checked while it was off? I had a sierra before now that was using a gallon of oil a week, turned out it was a couple of almost invisible pinholes in the sump!

Post by **Matt** » Sun Feb 11, 2007 8:35 pm

Im wondering about the 1st 2, but i have already discounted pin holes, because of where the oil is coming from....

Post by **bmcecosse** » Sun Feb 11, 2007 9:06 pm

There is no effective rear oil seal - it's just a scroll arrangement. If the main bearings are worn then excessive oil gets thrown at the scroll - and if there is crankcase pressure then that helps to blow the oil out! I would arrange for some effective negative crankcase pressure - connect one of the breathers to the inlet manifold via a 3 mm restrictor hole and make sure the other breather is clear. I did this on a Mini engine - slightly upset the idle of course - but what a difference it made!

Post by **rayofleamington** » Sun Feb 11, 2007 9:44 pm

if the rear scroll seal is leaking - the oild goes into the bellhousing. Can't see that this fits with Matt's description.

As you've tried the sumpgasket twice and didn't notice anything REALLY obviously faulty with the sump, then maybe it's time to have the engine out and find out if the bearing cap or backplate seal are faulty

(or maybe try a different sump just in case)

Post by **Matt** » Sun Feb 11, 2007 9:56 pm

and didn't notice anything REALLY obviously faulty with the sump

Errm it was rather dented but we bashed it back in to shape...

Unfortunately I dont have another sump to hand.

We have come to the conclusion its probably excess crank case pressure... the symptoms seem to make sense. Will play tomorrow morning! Where should there be vents... the top end isnt currently vented, but the bottom is, but with the vents at weird angles.... :s do you think this will make much difference?

Post by **bmcecosse** » Sat Feb 17, 2007 4:32 pm

Best vent of all is the original rocker cover vent - dunno why they ever did away with it. They need to be clear - and one connected to a vacuum source. But if it's that bad - the pistons/rings/bores may be on last legs.