P38 Diesel

Hi all, hope everybody had a good holiday. Iam haveing problems with the oil filter cap leaking, only does it after a long run or towing when engine is working hard. Have replaced the filter housing and the cap, the later several times. Still leaks oil. Thinking of buying the BMW parts just to see if they work any better. Any help is appreciated thank you, Bazz.

Could it be your crankcase is pressurising blowing oil out of it???

Hi Saint, what would cause that cos the engine has only done about 30k since a rebuild. Bazz

Possibly a blocked crankcase breather...

Wammers or Datatek would know more....

There was a thread about it not so long ago, have a search for it!

Ok thanks for that will give it a go, Bazz.

BAZZ said:

Hi all, hope everybody had a good holiday. Iam haveing problems with the oil filter cap leaking, only does it after a long run or towing when engine is working hard. Have replaced the filter housing and the cap, the later several times. Still leaks oil. Thinking of buying the BMW parts just to see if they work any better. Any help is appreciated thank you, Bazz.

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The replacement O ring that comes with some of the filters is under sized. I had the same problem, bought a different oil filter kit and the problem was solved.

Datatek said:

The replacement O ring that comes with some of the filters is under sized. I had the same problem, bought a different oil filter kit and the problem was solved.

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+1 of like mine it was warped overtime
If new o ring doesn't work try a new one of these
http://item.mobileweb.ebay.co.uk/viewitem?itemId=280706787886

Thank you everyone for the input will look into your suggestions this next week when its in for a service.

I've used a few different makes of filter but never (I know that's tempting fate) had a problem. I put the cap back on with a chain wrench and can feel the extra tightness as the O ring enters the housing. A little oil on the ring helps prevent tearing and lets it settle in the right place. I know there's an early and late filter, if your engine has been changed have you got an early engine in a late car or the other way round - and could be fitting the wrong filter - if the seal is different?

Speedex750 said:

I've used a few different makes of filter but never (I know that's tempting fate) had a problem. I put the cap back on with a chain wrench and can feel the extra tightness as the O ring enters the housing. A little oil on the ring helps prevent tearing and lets it settle in the right place. I know there's an early and late filter, if your engine has been changed have you got an early engine in a late car or the other way round - and could be fitting the wrong filter - if the seal is different?

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A chain wrench the plastic cap has a hex for a socket.
I don't think the wrong filter will fit and the filter is not the problem, it's the sealing O ring.

Yes, my cap has a hex but it’s really thin plastic and looked like it would shear easily with the torque needed to get the ring to enter the housing. A chain wrench just above the thread works fine, besides I haven’t a socket that size!

I guessed that the filters were different but are the O rings and is the wrong one getting fitted? I recall other threads about leaking caps. Perhaps we should resort to engineering and measure up the housing and groove and see if the supplied ring is sized right? My next change is a few weeks off and I’ll try to get some measurements.

Both my sons have BMW Z4’s and Forum’s for them list the O ring sizes for everything, perhaps we should have something similar for the P38? I know you can probably get O rings from LR – but maybe not all of them when they come as part of an assembly and that doesn’t help with these sorts of problems? Then you can always get one locally when you’re stuck.

Speedex750 said:

Yes, my cap has a hex but it’s really thin plastic and looked like it would shear easily with the torque needed to get the ring to enter the housing. A chain wrench just above the thread works fine, besides I haven’t a socket that size!

I guessed that the filters were different but are the O rings and is the wrong one getting fitted? I recall other threads about leaking caps. Perhaps we should resort to engineering and measure up the housing and groove and see if the supplied ring is sized right? My next change is a few weeks off and I’ll try to get some measurements.

Both my sons have BMW Z4’s and Forum’s for them list the O ring sizes for everything, perhaps we should have something similar for the P38? I know you can probably get O rings from LR – but maybe not all of them when they come as part of an assembly and that doesn’t help with these sorts of problems? Then you can always get one locally when you’re stuck.

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Here you are. Sealey Low Profile Oil Filter Socket 36mm 3/8Sq Drive SX114 | eBay

Speedex750 said:

Yes, my cap has a hex but it’s really thin plastic and looked like it would shear easily with the torque needed to get the ring to enter the housing. A chain wrench just above the thread works fine, besides I haven’t a socket that size!

.

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Two things, I can screw the cap down by hand and just need the spanner to nip it up. If the plastic is as thin as you think, a chain wrench is likely to crush it.

Speedex750 said:

Yes, my cap has a hex but it’s really thin plastic and looked like it would shear easily with the torque needed to get the ring to enter the housing. A chain wrench just above the thread works fine, besides I haven’t a socket that size!

I guessed that the filters were different but are the O rings and is the wrong one getting fitted? I recall other threads about leaking caps. Perhaps we should resort to engineering and measure up the housing and groove and see if the supplied ring is sized right? My next change is a few weeks off and I’ll try to get some measurements.

Both my sons have BMW Z4’s and Forum’s for them list the O ring sizes for everything, perhaps we should have something similar for the P38? I know you can probably get O rings from LR – but maybe not all of them when they come as part of an assembly and that doesn’t help with these sorts of problems? Then you can always get one locally when you’re stuck.

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Have you got the O'ring in the wrong place. Fits in the groove on the cap NOT under the lip at the top. Torque is only 25 Nm or 18 lb ft so not a lot more than hand tight on an item that big. You should be able to screw it in by hand easily when the O'ring is fitted correctly and lubed up.

I'm trying to help the 'leaky' guy, mines fine. Yes I'm putting the O ring right in the groove. I probably could get the cap on by hand but with oily hands I find it's easier to turn with the chain wrench - I haven't got a scaffold pole on the end, it just helps the grip. The hex on the top looks paper thin, the main body is quite chunky, it all depends where you want to apply torque.

Speedex750 said:

I'm trying to help the 'leaky' guy, mines fine. Yes I'm putting the O ring right in the groove. I probably could get the cap on by hand but with oily hands I find it's easier to turn with the chain wrench - I haven't got a scaffold pole on the end, it just helps the grip. The hex on the top looks paper thin, the main body is quite chunky, it all depends where you want to apply torque.

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God forbid you should get oil on your hands.

Interesting, have done most of these suggestions and it still leaks after about 3k or doing some work like towing duties. Had a thought of buying the BMW bits just to see if they were any better! The engine was rebuilt at around 67k and as done 30k since it is a late p38 but has the early engine. All ancillaries where swapped over as required even the oil filter housing. It as got to the point were the housing was changed and another new cap as been fitted. The garage and myself are a little stumpped to say the least as to what could cause this but will be looking into blocked filters/breathers etc. Most bits have been from Britpart but i have also fitted Land Rover bits and it still leeks?? Bazz.

BAZZ said:

Interesting, have done most of these suggestions and it still leaks after about 3k or doing some work like towing duties. Had a thought of buying the BMW bits just to see if they were any better! The engine was rebuilt at around 67k and as done 30k since it is a late p38 but has the early engine. All ancillaries where swapped over as required even the oil filter housing. It as got to the point were the housing was changed and another new cap as been fitted. The garage and myself are a little stumpped to say the least as to what could cause this but will be looking into blocked filters/breathers etc. Most bits have been from Britpart but i have also fitted Land Rover bits and it still leeks?? Bazz.

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Would not think it can be to do with blocked breathers.

The early type were metal and the late type plastic
The early had the shorter of the two filters .
The hex isn't there to assume how strong it is it there to loosen and tighten the cap

If you over tighten it then you better start worrying
Don't forget the spike has two orings as well.

Grit Valve said:

The early type were metal and the late type plastic
The early had the shorter of the two filters .
The hex isn't there to assume how strong it is it there to loosen and tighten the cap

If you over tighten it then you better start worrying
Don't forget the spike has two orings as well.

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Glad you said that. Could have sworn mine was ally and was beginning to think I was losing it. Almost went out to check!

Never had any issues with mine. From memory it has a copper washer on top as well and a tiny little o-ring on the end of the bolt that goes through.