hi my m8's vectra is a S reg and was running badly the oil and water was mixing badly and it was using them both so we thought it would be the head gaset, we took the head off but the head seems ok and the head gasket was ok, but the inlet manifold was really oily and it sounded like it was running on 3 cylinders . ANY IDEAS?

Vauxhalls had a nasty problem with the head going porous... sounds like that to me

but ther was no water in no.4 cylinder, so if it is porus would it make it missfire?

but there is a lot of oil... so either its coming from the head, seals/porous, etc or the rings have gone and its burning oil.

Still think it coud be a porous head if the water and oil is mixing and the head gasket is ok. Oil could be getting into the cylinder through a crack in the head??? did you check the inlet / outlet ports for anything nasty

Edit: Darn! Beat me to it!

If the gasket had no obvious marks where the oil / water had tracked, there aren't many other ways that would start the mayo machine.

You say the head seemed okay. Did you get it pressure tested?

There was an issue with the Vauxhall (non-coscast) heads going porous. This might explain it better:
Linky
The link suggests a sealant treatment, but I seem to recall someone elsewhere suggesting an alternative to join the 2 oil galleries - or maybe I dreamt it! I'll have a scout round.

Is this any use, too:
Camshaft cover breathers linky

Francis.

[Edited on 11/3/09 by mediabloke]

so reading the cashaft cover link would all the inlet manifold be shitty or would it jut be a ertain port, would a porus head cause the engine to missfire?

quote:

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Originally posted by *davies144*
so reading the cashaft cover link would all the inlet manifold be shitty or would it jut be a ertain port, would a porus head cause the engine to missfire?

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Vauxhall Astras of about that age have an oil to water cooler that's well known for corroding through and allowing oil and coolant to mix. Dunno whether Vectras had the same, but maybe that's where the oil and water are mixing ?

Dunno about the rough running though, did both problems start at the same time ?

[Edited on 11/3/09 by UncleFista]

If you have a V6 SRi they have an oil cooler in the water system between the "V" these leak and you get all the signs of a head gasket gone, particularly oil in the cooling system. Don't ask how I know. Vauxhalls price for a replacement cooler was as good as I could find any where.

Nick.

if its an S reg, it shouldn't have problems with a porous head? that was only really a problem with th C20XE engine, which they stopped doing before 98 didn't they? it would be an ecotec, but don't know what would cause your problems

I'm currently stripping a vectra sri with the ecotec engine. Will take a look tomorrow (if I get the chance) and see what I can see.

The one I'm stripping has leaked oil externally as well so could be the same thing maybe?

If it were a V6 I would say look at the oil cooler nestled in the middle of the V....