Trying to find oil leakage XUD9

This is the Forum for all your Peugeot Technical Questions, Problems or Advice.

Moderator: RichardW

User avatar
CPtje
Posts: 28
Joined: 01 Oct 2018, 15:42

Re: Trying to find oil leakage XUD9

Unread post by CPtje »

Nice, so it is okay to just remove one cylinder head bolt only. Will need to get the right socket wrench first and look up the right figure to fasten it again. Do I need to replace the bolt or can I re-use this one?

Replacing the HG is probably too difficult for me, so let's see if this will help.

User avatar
white exec
Moderating Team
Posts: 5972
Joined: 21 Dec 2015, 13:46
x 983

Re: Trying to find oil leakage XUD9

Unread post by white exec »

It's unusual to remove just one cylinder head bolt, but I don't think it will do any harm in this unusual circumstance.
Might be worth checking that it was actually properly tightened, when you get the socket and the torque figure.

If that O-ring in the corner of the HG goes leaky, engine oil under pressure (up to 6 bar) can find its way in various directions. It can leak across the HG and into a nearby waterway (you then get engine oil injected into the coolant), or into the neighbouring cylinder (unusual, because the HG is reinforced around the cylinder bore - causing the engine to burn oil), or leaking across the HG into the ouside world (oil dribbling from the HG and down the side of the engine).

What you seem to have (oil around the head bolt) does seem to be consistent with the O-ring going leaky. Just my best guess.

User avatar
myglaren
Forum Admin Team
Posts: 17656
Joined: 02 Mar 2008, 14:30
x 869

Re: Trying to find oil leakage XUD9

Unread post by myglaren »

white exec wrote:
09 Jun 2020, 13:15
What you seem to have (oil around the head bolt) does seem to be consistent with the O-ring going leaky. Just my best guess.
Is this not a common problem with the XUD or was that another PSA engine?

User avatar
white exec
Moderating Team
Posts: 5972
Joined: 21 Dec 2015, 13:46
x 983

Re: Trying to find oil leakage XUD9

Unread post by white exec »

It was a common problem with XUD. On BX diesel, a poor header tank arrangement (just a large air gap at the top of the radiator on some models) could lead to air locks and hot-spots in the head, which warped the head and allowed the HG to leak. The oilway captive O-ring (part of the HG) could also bake hard and go leaky. Same thing not unknown on XM 2.5, if cooling system is neglected.