Oil leak

[Dan]

Guys - I appear to have an oil leak, just looking for an idea of complexity if I've got the right culprit...

I've not had a chance to get the car up in the air to check underneath but I've got a fine mist of oil over the back bumper as the obvious symptom. Checking from above and below with a torch shows that the gearbox is dry (i.e. not driveshaft seals), in fact the only place that is obviously wet with oil is the front of the engine undertray and pretty much equally on either side of the block low down (e.g. by the offside engine mount). The oil pressure gauge is reading normal pressures at idle and at speed, the engine oil level is down a little, and the leaked oil tastes/smells like engine oil where it has dripped off the bumper onto the garage floor. I have both an engine undertray and a gearbox undertray, so I'm surmising that the lost oil is coming out of the front of the engine undertray and being blown back until it accumulates on the back bumper.

Looking at the parts manual, the front crankshaft cover is in the right place to be the source of the oil, and would explain why both sides of the block are wetted equally - well, it's coming from the front low down and that's the likely candidate. The car's due in for a C-service this winter anyway, so I'll just bring that forward a couple of months and get this done too. If this is indeed the source of the leak is it an in-situ job or an engine-out job?

[pitstoppete]

A common thing it could be, especially if its done a few too many miles or has more power than stock, is the main bearing ladder/block fretting under power, this is occurring on mine, it ooses black oil, even when the oil is clean. this is because the fretting alloy blackens the oil up as it exits past the seal, (black like what is on the rag when you polish alloys) which is probably well past it anyway

I asked Garry K about this same problem on mine, he suggests the block/main bearing ladder join will need stoning down, stud/bolt holes slightly countersunk to relieve the area, maybe extra bolts like the works cars had fitted between the existing bolts and careful re-assembly with Wellseal. This all sounded very good practice to me anyway and when mine comes out at some point, it'll get done. Must plant that money tree too........

or it could be the crank seal,

or it could be an M8 (IIRC) stud down at the front holding on one of the brackets on the front face of the block/ladder thats supposedly sealed in with Wellseal/similar

sump seal? dodgy sump plug?

Edited October 25, 2007 by pitstoppete

[Autocross7]

My vote goes to thecrank seal. This is a notoriously leaky spot on my car and others I have seen. Not to much to replace and the work, while teadious, is simple enough to do. Getting that thing lined up and fitted exactly correct is a bit hard... and it will prob start leaking a bit again after six months or so....

How is the timing belt though? If the crank seal is pooring oil - I would bet the time belt is black and a bit greasy as well. Get the car warm and run your fingers around the front side of the cam towers (car off of course). If it is greasy and black your crank seal is at least part of you leak.

I replaced the crank seal, valve cover seals (top and ends), oil pump seal, and iintake runner seal (not oil associated) a while back and the car still dripped a little. A Lotus expert in town (now retired) told me to "worry if it stopped leaking and drive it"! Mind you, it is a slight drip that seems to occour as the car cools down. The dip stick level hardly changes of time - a tiny bit down after a year...

Drive topless!!!

Cameron