18 replies to this topic

[Steve-O 2014]

We have excessive oil dripping from the split pin on the bottom of the gearbox / bell housing even after the engine has been sitting for a few seconds ticking over from cold.

 

What can cause this?

 

Thanks

[myredmini]

Crankshaft oil seal. Your clutch will become contaminated with oil if not sorted asap.

[Jordie]

Clutch oil seal

 

The split pin is there to keep the hole unblocked so the oil can drain out to prevent it getting onto the clutch friction surfaces.

[Turbo Nick]

either a worn primary gear or the oil seal behind the flywheel.

[lewBlew]

Agree with the above, it's the clutch oil seal aka the 'red seal'. Unless you have a posh driveway which you don't fancy getting oil on I would leave it, as to replace it and save the clutch involves removing the clutch.... So you might as well wait for the clutch to start slipping and replace the clutch and seal at the same time.

 

I've been waiting 2 years for my clutch to go but it's still fine, just drips a little.

[sonikk4]

I'm in the process of changing my primary oil seal and clutch as I type this ( tea break) and it's a pain in the backside.

[DomCr250]

Agree with the above, it's the clutch oil seal aka the 'red seal'. Unless you have a posh driveway which you don't fancy getting oil on I would leave it, as to replace it and save the clutch involves removing the clutch.... So you might as well wait for the clutch to start slipping and replace the clutch and seal at the same time.

 

I've been waiting 2 years for my clutch to go but it's still fine, just drips a little.

Good advice, just because it's dripping a bit it does not mean it's going to actually cause the clutch to slip. Just put a drip tray under it when you park at night.

[creakyjaws5533]

Its okay if the engine is out ive just done it on the metro I have the correct tool for installing the seal which makes life a lot easier and gets the seal seated properly

[Steve-O 2014]

Annoying thing is the previous owner said the engine is a fresh rebuild from Lincoln Mini Centre with recon gearbox so seems strange why its leaking, Its also leaking in a few other places around the engine.

 

Is it possible the previous owner (who said the engine has only done 12 miles max) has used a thinner oil for running in and its leaking out the seals or just put too thin of oil in to begin with?  I can't see how a rebuilt engine could leak so much. After it sat for 2 weeks without running theres a huge oil patch

Edited by Steve-O 2014, 25 March 2014 - 09:14 PM.

[cal844]

You could try a thicker oil after 500 miles :)

[Youngowner93]

Annoying thing is the previous owner said the engine is a fresh rebuild from Lincoln Mini Centre with recon gearbox so seems strange why its leaking, Its also leaking in a few other places around the engine.

 

Is it possible the previous owner (who said the engine has only done 12 miles max) has used a thinner oil for running in and its leaking out the seals or just put too thin of oil in to begin with?  I can't see how a rebuilt engine could leak so much. After it sat for 2 weeks without running theres a huge oil patch

 

It is very easy to just 'nick' the seal when putting the flywheel housing back on.

[Shep76S]

Mines been doing it for years, just means the clutch slips a bit when pulling away when cold.

[Steve-O 2014]

 

Annoying thing is the previous owner said the engine is a fresh rebuild from Lincoln Mini Centre with recon gearbox so seems strange why its leaking, Its also leaking in a few other places around the engine.

 

Is it possible the previous owner (who said the engine has only done 12 miles max) has used a thinner oil for running in and its leaking out the seals or just put too thin of oil in to begin with?  I can't see how a rebuilt engine could leak so much. After it sat for 2 weeks without running theres a huge oil patch

 

It is very easy to just 'nick' the seal when putting the flywheel housing back on.

 

 

but it is leaking in about 5 other places which is making me now think that the oil is too thin maybe? 

[KernowCooper]

Or its not been assembled very well, easy to damage the big red seal behind the clutch, but if its leaking from other places like between engine/box or timing end it points to assemble issues

[tiger99]

Yes, I agree, most probably not assembled well. Proper use of either PVC tape, the official tool, or the inexpensive substitute, on the primary gear splines and shoulder to protect the seal from sharp edges when fitting can prevent this. Sealing is such a precise and delicate thing that scratches which can hardly be seen under a magnifier are sufficient to cause significant leakage. It is definitely odd that it leaks elsewhere, as putting an oil-tight assembly together is not exactly rocket science. I wonder if the little bit of silicone where the half-moon seal meets the "sump" gaskets, and where they meet the transfer case gasket, was forgotten. Overlaps and T junctions do not seal well without assistance. It could also be leaking around some of the internal transfer case bolts, and again some silicone can fix that, which only happens if they have been drilled too deep into the main gearbox case.

 

The other possibility is that the primary gear bushes are in poor condition, and oil is leaking through them. It is only kept out by being centrifuged out via the holes in the gear when the drive train is spinning, and with engine off, or clutch disengaged, engine running (i.e. when about to set off), there is nothing preventing residual oil dripping down inside the transfer case from attempting to find its way out through the bore of the gear.

 

But they ALL (not just Minis, almost all cars with a manual clutch) drip at the jiggle pin to some extent, and it rarely gets to the clutch surfaces, so unless the oil loss is excessive most people just live with it. The other external leaks are, however, unacceptable, although again people would live with them if the oil loss and mess caused were tolerable.