Oil leak

[tim22]

I have a oil leak that appears at the front of the sump dripping from the middle of the half round section behind the bottom pulley.

My first thought was that the cork gasket between the front cover and sump was leaking but the amount of oil is significant (a puddle several inches across formed in a few minutes) so now wondering whether that amount of oil could only be caused by it being pushed out past the front bearing seal and oil thrower?

The point is that I don't want to drop the sump and replace the sump gaskets if there is a chance the engine has to come out anyway because the problem is more likely to be with the bearing seal so it would be very useful to know the most probable source of the leak.

I haven't yet checked for loose sump bolts but the other question is assuming the bolts are correctly torqued whether slightly over-tightening the bolts holding the sump to the timing cover would help stem the leak or more likely make the leak worse?

Any ideas please?

[elancoupe]

It sounds like the front crank seal is the culprit - I just did mine last summer. Remove radiator, take off the belt and remove the crank pulley. A puller may be needed for the crank pulley, be careful, the stock cast pulley chips easily. The seal can then be pried ( or prised ) out. Just be careful not to push the new seal in too far. A little Wellseal or equivalent on the seal edges is a good idea. You may also find a wear mark on the crank pulley which could contribute to the leak.

Sometimes, a DPO has not centered the front cover on the crank, which makes sealing a challenge.

[tim22]

Thanks for that ... I had assumed the seal would need to be pressed out of the front cover so it doesn't sound nearly as bad a job as I had feared.

Can you please explain how the crank pulley could be worn and how this would contribute to the leak - do the pulley and the seal come into contact?

[elancoupe]

The crank seal rides on the pulley, not the crank, so years of service can actually mar the pulley. My pulley is steel, and the seal has worn a slight mark in the anodizing.

I had problems with a rear gearbox leak, and was amazed at how worn the driveshaft yoke was at the point of the tail shaft seal , the yoke had to be replaced.

[tim22]

Got you! I will check the pulley as you say.

If the leak has only developed recently can I assume this is age-related and rule out the front cover not being centred on the crank or is it important that I check this before replacing the seal?

[512BB]

Tim,

You cannot assume anything with a Lotus, as when you do, you can make an ASS of U and ME. I love those old Benny Hill jokes. I think I have done that one before. Taxi...........

It is unlikely that a sudden oil leak will be caused by wear on the crank pulley, as wear in that area takes place over a long period. However, once you have removed the pulley, you need to check it, to see if a groove has developed and how deep it is. The front cover oil seal allows for quite a lot of wear on the pulley before it will leak. Should a groove have been worn, you can have the pulley sleeved if you have a lovely old cast pulley, which are quite valuable, or fit a new steel one.

Whilst you have the pulley off, fit a new front cover oil seal, as a failure of that seal is probably the cause of the leak. Prise out the seal carefully, using a block of wood between your prefered priser and the cover. Make sure you grease the new seal and pulley before bringing the two together, to save tearing the seal on start up.

You could heat up the front cover in the area of the seal, with a hair dryer. That will aid the removal and replacement of the lip seal. Your Mrs wont mind

Leslie

[john.p.clegg]

To digress a little,can anyone explain the pro's and con's of cast v steel pulleys?
Thanks
John

[types26/36]

Never seen it myself but have heard the cast type can shatter, the steel type is also available with a smaller diameter.

[rgh0]

The pulley was probably originally cast as it was the cheapest way to make it in volume. The rear v belt flange is also very thin and prone to cracking damage when removing the pulley if you use a standard 3 leg puller rather than a bearing splitter.

A steel pulley can be made lighter and is tougher and not so susceptible to damage. Unless it is hardened the oil seal will wear a groove faster also.

cheers
Rohan