Oil on No.2 Spark plug (VR6)

[andy 0]

Decided to change my plugs today, whilst in the hunt for the infamous eratic idle, upon removing the plugs, No.2 (Front left) had loads of oil on the threads, not on the electrode at all, in fact that looked pretty healthy. The others were ok, what is this likely to be?? I'm guessing its either come up from below, ie dodgy ring (oh er) :shock: or from above, more hopefully valve stem seals. What do you think chaps?

[dazzyvr6 0]

sounds more like a weeping cam cover gasket if its only on the threads

[andy 0]

I don't think it's that, I so wish it was! There's no sign of leakage externally, unfortunately, plus the threads are in the head and it came out oily, its like oil has been forced under pressure up and arround the threads. After a compression test I found pots 5 and 6 were at half pressure too, I know the head is going to have to come off to fix that I'm just hoping I haven't got bottom end trouble. It still goes like a scalded cat!

[dazzyvr6 0]

the oil could of got on the threads when you took the plug out :? it only takes a small leak and it would collect in the spark plug hole,did it smoke at all when you replaced the plug and fired it up?

[Dub Style 0]

mine had exactly the same on the same cylinder, plug was dry but threads had little oil

[andy 0]

No it didn't smoke, never smokes as a rule. You're right it could have collected down there, the side of the head is as dry as a bone all the way round though so I'm not sure its that. It would be nice if it was though :-)

[Roger Blassberg 0]

I would think that it is just oil that got down the plug recess when you last topped it up, and has been lurking down there ever since.

 

Best wishes

 

RB

[andy 0]

Its a long way from the oil filler hole, plus the oil was distinctly used. I'll have to monitor it I think.

[2cc 0]

well at least it won't get stuck in the thread

[andy 0]

This is true! I'm just concerned that it may be coming from below.

[samm_cvr6 0]

I had exact same kind of problem, but you can't always clearly see oil leaking from outside the cylinder head, you may see more to the right of the block, if you go real close and look to where the gasket is?

But if it is the rocker gasket, which I hope it is, your VR should be running really rough, and you say it isn't which makes me think it is something more serious....

Could maybe ber worn valve seals??

[Roger Blassberg 0]

if it is the rocker gasket, which I hope it is, your VR should be running really rough

I don't follow this line of argument (but am always open to persuasion!!). How would it cause rough running?

 

A weeping cam cover gasket is much more likely to cause oil to get onto the threads from above, and not onto the electrodes, than worn guides/seals which would cause black oily deposits on the combustion chambers and electrodes.

 

Best wishes

 

RB

[samm_cvr6 0]

Depends really on the general condition of the engine, how many miles it has done, how hard it has been driven and how it has been serviced too.

Eventually, I think if you leave it long enough, the oil, again depending what kind of oil viscosity, should really be Synta Silver tho, may seep down.

I can only tell you of my personal experience of my VR and this is what happened, so it isn't a definitive answer as such.

[andy 0]

Engine is sweet as generally, 105k miles, regular synta silver changes. Can't see how leaking gasket would cause any running problems either. It would be nice if thats the problem because I have a spare one sat there, it just doesn't appear to have leaked on inspection.

[Henny 0]

Eventually, I think if you leave it long enough, the oil, again depending what kind of oil viscosity, should really be Synta Silver tho, may seep down.

I can only tell you of my personal experience of my VR and this is what happened, so it isn't a definitive answer as such.

 

So you're saying that a small amount of engine oil, under no pressure, managed to seep its way past the compression washer on the sparkplug, around 12mm of thread (which was tightened and along with the washer stops several bar of pressurised gas escaping from the cylinder when the engine's running) and into the cylinder?

 

Hell, get me some of that oil, it sounds better than Plus Gas! :roll:

 

Personally, if it's on the thread but the tip is clean/normal, I'd go with the "small puddle sat in the spark plug's chamber (around the hex bit of the sparkplug) which has transferred onto the thread as you removed the plug" theory as the only plausible one... 8)

[samm_cvr6 0]

Hey guys, I asked myself the very same question, but trust me, I shi* you not, my VR was running so bad it would hardly even accelerate, changed the £10 rocker gasket and hey presto, she flies!

I was however, having a similar problem a couple of months ago, but it was down to the dizzy cap and rotor arm being all seized up with gunk, so I changed them, new leads, plugs and all filters and again, it was fine, guess I was lucky on that side...

[andy 0]

I think it must have been something else you disturbed whilst changing the gasket mate, lets face it, cam cover gasket is not that straightforward on a VR6, you would need to get the ht leads off etc, inlet manifold, throttle bits etc.