Cylinder Head - Xantia

sandancer · Post by **sandancer** » 02 Sep 2003, 01:11

6 weeks ago it was the suspension spheres changed. Last week I tackled the cambelt (what a 'mare!). Now it looks like the cylinder head...[:(]
The car: 1.9TD Xantia, 98R, 62K miles.
The symptoms: Noise during acceleration that sounds like a blowing exhaust. Oil seepage out of the rear of the cylinder head gasket. Higher than expected back pressure out of the oil dipstick (keep finger on hole and after about 15 secs is enough to force finger out of way). There are no bubbles within the coolant, and no noticeable loss of oil. I cannot locate any exhaust leakage plus it's hard to hear with the engine not loaded, just the noise from within the car in the region of under the dash.
Am I looking at a head gasket change and, if so, what are the pitfalls, how much time am I looking at etc? (ie how easy is it...[:D])
Mark.

CITMAN · Post by **CITMAN** » 02 Sep 2003, 01:54

Sounds like a bit of blow by were combustion gases are getting past the piston rings. However more likely its a blockage in the breather system causing pressure. Head gasket problem would result in excessive pressure in the cooling system depending on the way in which it has failed. As they can fail in a number of ways but none of them would result in the pressure in the oil system which you describe which brings me on to the breather system and blow by past the rings. But I do agree that the headgasket does seem to be leaking a bit from your discription of the oil leak. However if its not to bad and if it were mine I would leave it unless oil is getting on the cambelt, cooling system hoses etc.

NiSk · Post by **NiSk** » 02 Sep 2003, 02:07

Check the compression on all cylinders. That will tell you without a doubt if you have a leaking gasket!
//NiSk

sandancer · Post by **sandancer** » 02 Sep 2003, 02:49

What sort of compression pressures am I looking at? I take it I plug the tester into the injector socket, remove the cable to the stop solenoid (or in my case dont key in the security code so the engine won't fire) and crank the engine?
Mark.

jeremy · Post by **jeremy** » 02 Sep 2003, 05:42

Diesels have colossal compression - probably 600 psi (40 bar) or more. Does your compression tester go this high?
If the head gasket fails the gasses are either going to go into another bore (as happened to me) in which case the engine won't run properly as its 2 cylinders down and in fact will probably need to be revved brutally to get it to run at all. If the gasket has blown it is probably possible for it to blow to the outside and miss a waterway at first. The oil visible is probably unburnt diesel fuel rather than lubricating oil.
If the crankcase is pressurising then its either bore/ring/piston problems or a head gasket blow into an area communicating directly or indirectly with the crankcase. The most likely area would be into an oil return drain at the end of the head.
Don't leave it and hope. Despite the noise they make diesels are delicate and need to be in good order to function properly.
jeremy