engine oil leak

PostPost by: alfert » Wed Apr 18, 2012 4:55 pm

I just took my S3 coupe out for its first real ride since complete resto. A couple of round the block rides late last fall. Car ran great, good oil pressure, water temp etc. I am chasing an oil leak. The cam cover is not leaking, the filler cap is. However there appears to be quite a bit of oil dripping below the back of the engine. Although I can se wet/oil on the bell housing from the filler, I am having a hard time believing that it could leak that much. Could the rear main rope seal leak that much? Not trans oil, definitely engine oil. Car is perfect, I have to find this......
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PostPost by: simonknee » Wed Apr 18, 2012 5:01 pm

The seal around the rubbers in the d-cups can often be the source of leaks at the top rear of the head.
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PostPost by: alfert » Wed Apr 18, 2012 5:21 pm

The half moon seals are dry, the oil that is high up is from the filler. It has a cork gasket and I guess I will double it to make a tighter fit. The rest is somewhere low unless the filler leak is much more then I think.
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PostPost by: types26/36 » Wed Apr 18, 2012 5:39 pm

Check around the rubber drain-back tube that fits between the head and block, it can leak and run down to the rear of the sump.
Even the fuel pump mounting can leak a fair amount of oil.
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PostPost by: Galwaylotus » Wed Apr 18, 2012 6:13 pm

My filler cap was leaking and I bought a replacement seal from one of the well-known Lotus vendors. A year later and it had swollen to a far larger diameter from exposure to hot oil. I cut a section out of it to get the seal to fit inside the cap and it seems to be ok now - slit seal and all!! :)
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PostPost by: Chancer » Wed Apr 18, 2012 7:04 pm

Forgive me for jumping in with another oil leak question.

Can the water pump leak oil as well as water?

I have recently run my engine up several times to flush through the oil and water systems, its only the second time its been run in 25 years so I was expecting it to be incontinent!

The electric fan was pretty seized so I disconnected it and ran the engine up several times to between 100 and 110 degrees celcius.

The water pump seal would leak a little once the system was pressurised and above 90 degrees, some dripped down and some was thrown up by the pulley to settle in a band on both front wings, the last couple of times that I ran the motor in the last few minutes specs of engine oil were also being thrown out in exactly the same place on the wings.

I was running a very thin mix of cheapo oil and paraffin so am not particularly peturbed by the loss just where it appears to be coming from, there was no evidence of coolant in the oil when drained.

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PostPost by: types26/36 » Wed Apr 18, 2012 7:19 pm

Chancer wrote:Can the water pump leak oil as well as water?


I would take a guess that oil is more likely to be coming from:
1. out of the dip stick tube, either the dip stick is not all the way in or crankcase pressure is forcing oil up the tube.
2. Front pully throwing oil out?
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PostPost by: Panda » Thu Apr 19, 2012 12:31 am

Dave Bean used to make a natty little shield which bolted to the rear cam bearing directly under the filler cap. It stopped the oil splash from the cam lobe hitting the underside of the cap and thereby reducing the chance of leakage.
I don't know if still available, but wouldn't be hard to make.
cheers
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PostPost by: twincamman » Thu Apr 19, 2012 2:11 am

OK HERES A LITTLE TIP I picked up from a an old hot rodder -----buy some cheap SILVER paint [only silver] and spray the gaskets both sides and when the paint is dry put the gasket on and you will have no leaks EVER a little gasket maker on the D rubbers and you should have a nice leak proof top and bottom end dont know why it works it just does ---- ad a rubber PLUG END on the dip stick to control the pressure leak from the d s hole ==ed poor spellers of the world untie
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PostPost by: prezoom » Thu Apr 19, 2012 4:36 pm

My oil filler cap leaked just enough to piss me off. I made thin cardboard gasket, the same size as the rubber seal and placed it between the cap and the rubber gasket. It added just enough pressure to the seal, the leak went away.

On the dip stick, a 1/4 inch rubber grommet used to insulate wiring through a panel was slipped over the dip stick and a generic light throttle return spring was used to firmly keep the dip stick seated. No more oil leaks there either.

Also made my own seals for the cam cover bolts. No weeping there as well.

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PostPost by: nebogipfel » Thu Apr 19, 2012 6:31 pm

prezoom wrote:On the dip stick, a 1/4 inch rubber grommet used to insulate wiring through a panel was slipped over the dip stick and a generic light throttle return spring was used to firmly keep the dip stick seated. No more oil leaks there either.


I've found an old straight plug lead boot fits nicely on the dipstick tube ....insert stick through it, job done :wink:
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