Technical Oil in spark plug hole

[thedigger]

Morning all,

Serviced my wife's punto this weekend and when I removed the spark plug from hole #1, it was covered in oil (fresh oil, not burnt on stuff). The other 3 plugs were clean. I replaced the plugs, leads and oil/filter, but does this normally mean the "O" ring has perished (the engine's done 146k or so so it's had a good innings)

The car hasn't been misfiring, and it's rarely used (my wife probably does less than 100 miles a week in it)... is it worth getting the ring replaced, and any idea how much it would cost to repair (or is it DIY-able)

Cheers

 

[Moosey]

What engine does it have?

Sounds like a cam cover gasket, or cam box gasket if it's a two-part head. (Like the 1.2 16v.)

 

[thedigger]

It's the 8v 1.2 60ps engine.

The cam cover was changed a few months ago (probably less than 500 miles on the clock since), and there's no sign of it leaking from there. Also, it was on the actual firing mechanism and the lower part of the ceramic, but not on the thread, so I'd imagine it's not being leaked from above.

The oil seemed quite clean, more so than the stuff that came out of the sump (frightening that it can get so black in 12 months :yum

 

[Moosey]

Well, it can't have come from below, so i'd still bet on it being the cam cover gasket. There isn't anywhere else it could've come from.

 

[thedigger]

Ok, I'll check it out when I get home later. Cheers for the advice. Just seems strange that the top of the plugs (and the HT leads) were dry and the bottoms were wet (so much so that oil was dripping off when the plugs were removed)

 

[Moosey]

Did you replace the cam cover yourself?

It's possible if someone else changed it there was already oil down there, which they didn't clean out when the cover/gasket was changed.

 

[thedigger]

I changed it myself, and degreased the engine casing after (so I'm fairly certain it hasn't started leaking again).

I didn't dry out the first spark plug hole after doing this, although I would have thought it would have burnt off by now?

 

[Moosey]

The cylinder head won't get hot enough to burn oil in the plug well. (Be thankful, or your car would've caught fire!)

The HT lead boot probably just kept it in there.

 

[DaveMcT]

Most likely some oil got spilled when the engine was filled. Anything else would be dirty oil.

 

[Scoobysnacks]

I would agree with you all, but the op is saying that the oil was on the bottom of the plug, the bit that's normally inside the cylinder with lots of nice hot gases etc.

I would bet that what's happened is while filling or topping up the oil, you've managed to spill some down the back of the engine. It's dead easy to do with the silly layout!

If there's no other symptoms assume the simplest thing, i.e. oil in the plug well that has transferred to the plug on removal.

Give it a good clean off and stick it back in.

There isn't an O-ring as such on the plugs. They have a soft washer that is compressed slightly on tightening to aid sealing. They are normally integral to the plugs and never really need changing.

 

[Moosey]

Could be the elves. They make mysterious oil leaks, hide your keys and tangle your headphones when you're not looking. Among other thing. Annoying little buggers, impossible to catch them in the act too!

 

[Scoobysnacks]

Could be the elves. They make mysterious oil leaks, hide your keys and tangle your headphones when you're not looking. Among other thing. Annoying little buggers, impossible to catch them in the act too!

Nah, it's not the elves you wanna worry about, they're pretty stupid and not very imaginative.

It's the piskies you wanna watch out for. They're clever little b#####s, and a sense of "fun" that Hannibal Lecter would be proud of!

They're the evil little sods that found out that smurf blood was good for sticking pictures to the wall!

Ok, off to take my pills now!

 

[Moosey]

You're not meant to drink the bong water, Scoob.

 

[Scoobysnacks]

Drink it? I snort the stuff!

 

[thedigger]

I'm fairly certain I didn't spill any in the spark plug holes this time (in fact, it's a moot point, I changed the spark plugs while the old oil was draining out). However, I definitely tipped a load of oil in SP1 a year ago (which also included a fairly disastrous attempt to try it out with a tampon... not being female, I didn't realise how much those things expanded ). Would that oil have just sat on top of the valves for a year without being burnt off??

 

[Scoobysnacks]

Easily. That particular bit of the engine doesn't get very hot. It could sit quite happily in the plug well forever until you pull the plugs.

 

[DaveMcT]

I have the HGT similar but not identical and that had some unused oil around the number one spark plug. Any oil from inside the engine would be brown or black and the oil filler is close by so its the only possible cause.

I cant imagine it causing a sparkplug missfire (oil is not conductive) but you never know. Unless its flooded with oil there is no need to worry about it and changing the plug will have shifted it anyway.