D5 163 Boost Leak Test Gone Wrong

[JozE]

Hello everybody

I was testing my 2004 S60 D5 163 for boost leaks using the homemade 'test kit' - a PVC pipe cap with a valve, attached to the air hose behind the MAF sensor, and an air compressor.

I found my leak, got it sorted, and then I retested @ 20 psi. At first there was no air escaping the system, but next something gave from whitin the passenger side of the engine as I heard the distinctive Pffffff sound. I had (and still don't) no idea what that could have been, I drove the car and it was just fine.

Fast forward a couple of days, I discovered oil dripping around the back of the lower gearbox mount area which could be traced up to the rear of the engine (around the drive shaft level where the flywheel teeth are sticking out) to what seems to me is between the engine block and the crankcase.

When testing I kept the oil cap on as I noticed that the system would not hold pressure otherwise.
I have obviously managed to destroy something but I wonder what it could be? First thing that comes to mind is a gasket or a seal of some sort but I wonder if it could be something else? Any suggestions will be greatly appreciated.

Many thanks.

[davebb]

Hi when I do a pressure test I do leave the oil filler cap off because of this,
I don't put pressure at the air intake hose at the maf, you can use very low pressure there 5 psi max as the air intake pipes are not made for pressure,
I got a cheap silicone 90 bend pipe and connect that to the turbo, and blank of the pipe that fits to the engine inlet, so now you can pressure it to 20psi
and leave it for 5mins to test the high pressure pipes and turbo compressor seal, and intercooler, egr valve/housing, one you know that is all ok , then reconnect the inlet pipe to the engine then run the test again at lower pressure
as you will have air going in to the crankcase past the piston rings as the engine is not running and is not oiling the pistons and the engine is cold not hot so the rings are not sealing as well,and it will not hold high pressure as some valves will be open, so you may have blown a crank seal, as the crankcase (should not be pressurised) you have filled the crankcase with 20psi,
that is 20 pound per square inch ,what is the volume of a D5 crankcase ?
some car tyres only have a bit more pressure,
so to get 20 psi on your gauge with air also leaking out of some valves, you are putting a lot of air in to the crankcase, remove the starter motor and look if you can see any oil,
also when your car is running at full boost 17psi, or remapped 20-21psi the crankcase is breathing there is a breather pipe going into the cold air pipe,(you have put 20psi into this breather pipe) so there is not any pressure in the crankcase when the turbo is working as air is getting sucked out of the crankcase by the breather to the turbo inlet pipe
you can see this by using a rubber glove by putting it on were the filler cap fits then rev the car and any air will be sucked out of the glove,
Good luck,
Dave

[JozE]

Thanks for your reply, I see what I did wrong. I will double check where exactly the oil is coming from but it seems that put the last nail in the coffin of that lovely S60

[davebb]

Hi please let us know how you get on,
Thanks Dave

[Simmy]

Originally Posted by JozE

Hello everybody

I was testing my 2004 S60 D5 163 for boost leaks using the homemade 'test kit' - a PVC pipe cap with a valve, attached to the air hose behind the MAF sensor, and an air compressor.

I found my leak, got it sorted, and then I retested @ 20 psi. At first there was no air escaping the system, but next something gave from whitin the passenger side of the engine as I heard the distinctive Pffffff sound. I had (and still don't) no idea what that could have been, I drove the car and it was just fine.

Fast forward a couple of days, I discovered oil dripping around the back of the lower gearbox mount area which could be traced up to the rear of the engine (around the drive shaft level where the flywheel teeth are sticking out) to what seems to me is between the engine block and the crankcase.

When testing I kept the oil cap on as I noticed that the system would not hold pressure otherwise.
I have obviously managed to destroy something but I wonder what it could be? First thing that comes to mind is a gasket or a seal of some sort but I wonder if it could be something else? Any suggestions will be greatly appreciated.

Many thanks.

you may have blown out the oil gallery core plug . a well known weak point on this engine £3 part £250 repair as the gear box has to be removed to replace it

[aland]

Originally Posted by Simmy

you may have blown out the oil gallery core plug . a well known weak point on this engine £3 part £250 repair as the gear box has to be removed to replace it

Yep, sounds like it.
To the OP, this core plug is behind the flywheel, so the gearbox etc needs to come off to access it.
Later cars had an improved plug design, which you can fit to the earlier engines so solve it once and for all.