2.5tdi (BDH) rear crank seal

[blancy]

Rear of engine and gearbox covered in oil. Had a look underneath with undertray off, cleaned it up some and ran the engine and within a minute I've got oil appearing on both sides. Very little room to see the source but based on the rough location I'm thinking this could be the rear crank seal. I'm finding it hard to find any info about the replacement of this. Has anyone replaced one? Any idea where I might find some info?

Thanks

[spartacus 68]

Search out ErWin, you can source specific model and buy access to see procedure involved. Suspect it’s going to be very difficult to do unless you have access to a ramp.

[Magnet]

Worth taking note of a current thread on this issue. Please search. 

[blancy]

2 hours ago, Magnet said:

Worth taking note of a current thread on this issue. Please search. 

Thanks.  Do you mean the Q7 one?  Not too much info in there if so

[blancy]

3 hours ago, spartacus 68 said:

Search out ErWin, you can source specific model and buy access to see procedure involved. Suspect it’s going to be very difficult to do unless you have access to a ramp.

I'm on the road with axle stands 🙂   Probably even struggle with clearance to get the box out!  Flipping nightmare.  V6 into A4 equals not much room for any job I've done so far.  Just grabbed some wheel bearings and front driveshafts too but doesn't even feel worth trying these until this leak is resolved one way or the other.  May have to bin the car which would be a shame as, whiilst it's getting on at 240k, it drives lovely.

I'm assuming it's the crank seal rather than the sump as there's a lot of oil above the line of the sump.  Any sure fire way of confirming?

Anyone ever had the job done by a garage?  Any ballpark figures?

 

Thanks

[Magnet]

Hello John,

I do feel for you. In your situation, I think it would be a ‘good investment’ to spend an hour’s labour with a trusted local garage, with a view to better sourcing the site/s of the leak.

Kind regards,

Gareth. 

[cliffcoggin]

If it is the crankshaft seal that is leaking, there is a distinct possibility that after 240000 miles the sealing surface on the shaft is also worn to the point that a new seal will not stop the leak. That would be a very expensive fix, and to cap it all you won't know until the engine is stripped.

[blancy]

4 hours ago, Magnet said:

Hello John,

I do feel for you. In your situation, I think it would be a ‘good investment’ to spend an hour’s labour with a trusted local garage, with a view to better sourcing the site/s of the leak.

Kind regards,

Gareth. 

That's not a bad idea.  I hope they will entertain it

 

[blancy]

57 minutes ago, cliffcoggin said:

If it is the crankshaft seal that is leaking, there is a distinct possibility that after 240000 miles the sealing surface on the shaft is also worn to the point that a new seal will not stop the leak. That would be a very expensive fix, and to cap it all you won't know until the engine is stripped.

Aye, 'tis a bugger 🙂   I was just looking at a picture of the back of a 2.5tdi engine and looks like the sump actually comes up to the bottom of the crank seal.  I've had a mild leak for years - thought it was the sump and was planning to possibly finally have a go at that once the weather was better.  This much increased oil leak has been relatively sudden.  From underneath it looks like the fresh oil is coming from higher up than the sump.  Would a rear crank seal mainly leak from the bottom or could be anywhere on it?   Any other possible suspects (manifesting on both sides makes me think something fairly central?)

Also, when  had the car up on axle stands yesterday (so tipped backwards in effect) it wasn't leaking until I ran the engine then fresh oil would start to appear within 30 seconds on both sides, gathering then dripping off the flat undersides of various things.   I'm wondering the 'tipping up' exacerbates the issue.  And does the fact that leaks much more obviously when running help to rule anything out as the source of the big leak (such as sump)?

Edited Monday at 04:34 PM by blancy

[cliffcoggin]

That it leaks more when the engine is running suggests it is the shaft seal.

Speculating further, is it possible the crankcase ventilation is not working properly? I am wondering if excess pressure in the crankcase is actively blowing oil out.

[blancy]

1 hour ago, cliffcoggin said:

That it leaks more when the engine is running suggests it is the shaft seal.

Speculating further, is it possible the crankcase ventilation is not working properly? I am wondering if excess pressure in the crankcase is actively blowing oil out.

That's possible if it's something that needs to be cleaned / replaced from time to time.  I've had the car 8 years and have not done anything with regards to that.  It's been mostly normal routine stuff like oil, suspension, brakes, timing belt and the bits, new water hoses as they have gradually perished.  Any term in particular that I should google to see if that's something I can try?  I'll start with 2.5tdi crankcase ventilation 🙂

 

Thanks for your input all

[cliffcoggin]

Search for EGR (exhaust gas recirculation).

[Stevey Y]

1 hour ago, blancy said:

That's possible if it's something that needs to be cleaned / replaced from time to time.  I've had the car 8 years and have not done anything with regards to that.  It's been mostly normal routine stuff like oil, suspension, brakes, timing belt and the bits, new water hoses as they have gradually perished.  Any term in particular that I should google to see if that's something I can try?  I'll start with 2.5tdi crankcase ventilation 🙂

 

Thanks for your input all

Hi I really would not bother with the crankcase vent at the moment, the rear seal wont leak when the engine is static because the crank is not revolving, when the engine is running it will leak 360 degrees I would doubt the crank is worn, billet steel verses rubber, only ever going to be one winner, I had mine changed [2.0 CNHA] but they are basically the same, box out, flywheel off, ring gear plate removed then the seal unbolted it sits in a metal housing with the crank position reluctor ring, the engine will need to be timed to tdc on cylinder 1 and the witness mark on the reluctor ring directly opposite the marker on the casing, its a mission as you will need to replace the driveshaft seals as well as they are one hit wonders, the timing and pinning is crucial as if the reluctor ring alignment is not exact it wont start.

Steve.