My sei sporting MPI's due a timing belt, so while thats off i'm going to change the water pump too. the question is, the spark plug on cylinder 1's normally covered in oil, while the garage is doing the belt/water pump is it worth stripping the engine and doing the head guasket and sorting out the oil problem, i think its either a valve seal or a piston ring, or should i just wait for it to die?

You sure it's oil?

Anyway, a compression and/or blowdown test should reveal where the problem is. No point at all in stripping things without reason.

What kind of mileage has the engine done?

fingers99 said:

You sure it's oil?
What kind of mileage has the engine done?

Click to expand...

its about 73-74k its done about 30k in the last 22 months.

I do a service on it every 6 months tho, without fail.

Cambelt and tensioner, water pump for preventative reasons only. I'd get a blow down test done before anything else. A lot depends on the skill of the man with the stethescope, but it should reveal all!

I've never heard of a blow down test, whats that do?

Basically you remove each plug in turn and connect the cylinder to an airline. The air will escape and can be heard or seen. Generally, it's both more multifunctional and accurate than a compression test.

ask for a cylinder leakage test at a garage, we does this regular, its basically a gauge on the air line which is sensative to slight leaking from the cylinder and will show up a blown head gasket by reading high on the gauge

But done well, you can listen for (or see!) where the air is escaping from, thusly, you can pinpoint leaking valves, worn rings/bores, even tell not only which cylinder but how a head gasket is compromised.

Re the oil on the plug, are you sure it is oil? Might be worthwhile swapping the injectors around (if MPI). Be careful getting them out: do not lever on the plastic electrical connector bit or it'll snap off!

oil on plug number is just spilt oil from filling the engine oil up, it sits on the threads and then when you remove the plug it drips onto it. don't worry about it.