Oil on the spark plug...

[krimsalt]

So noticed a bit of an imbalance in the engine shaking and decided to investigate. I did a compression test and noticed oil drenched the first spark plug and a bit of oil on the other three plugs... The compression test showed 180psi for that cylinder and 185, 185, 179 for the other three.

I believe it's the o-ring seal where the spark plug gap is, or the valve cover gasket. I'm praying it's not a cracked head although i find that unlikely...

Just wondering if anyone else has had experience with this situation and could tell me what other things to look out for as tomorrow I'll be divulging into the engine to replace o rings and valve cover gasket. In hopes the problem is resolved.

2007 Mazda 3
116700km
2.3L

[Wes08M3]

Bad valve cover gasket won't cause oil on the plugs. Valve seals on the other hand... When you say o-ring seals are you referring to the o-rings that seal the "tube" where the spark plugs are inserted? Those going bad could cause some oil on the plugs.

Have you noticed it burning any oil at all?

[krimsalt]

I did notice low oil level. I had maybe a liter and a half in when my oil was changed 3000km ago. So yea, no leakage so it has to be burning? And yes those are the o rings I am referring to

[Wes08M3]

Hmm 117 000km is low to be having problems with the valve seals, but certainly not impossible. I know that those "tubes" are threaded into the head and may also allow oil to get by. At least, they were threaded on 2.2L 4cyl's from Toyota that I've worked on. Often times we removed the tubes and applied Teflon thread sealant to the thread to prevent oil leaking onto the plugs. You could try that for good measure provided they are also threaded into the head.

[krimsalt]

Well it turns out the Valve Cover gasket was thinned out. also some bozo idiot dirtback crack adict who owned the car prior to me had changed it before. I noticed that because the bolts holding the valve cover on were able to be twisted off by hand... as well as the valve cover had a nice chalk number on the inside which really struck a nerve as that means this has been replaced before.

The 3 inner rings were thinned out causing oil to appear to leak into the cup where the spark plugs sat. I'm guessing oil leaked down onto the plugs as the white parts of the plugs had oil and oil was also deposited in the coil packs for each plug.

with the Valve Seals, I don't believe they are bad to be honest. I park underground and in the mornings when the car is cold and the catalytic converter has not warmed up it would not be able to properly burn oil and there would be a strong scent of oil. The only other way I could confirm this is if i get a small camera snake and look into the 1st cylinder after the car has sat off for a while and see if there is an oil build up.

[Wes08M3]

Yeah I wouldn't be too concerned with the valve seals at this point. If those gaskets were dried out, I'm sure that was the problem, or at least a big part of it.

Sounds like someone has butchered the job once before. Just keep an eye on it and let us know how it turns out.

[DanScarps]

I wouldnt crucify your valve seals yet. You were likely losing oil from it leaking out of your valve cover, then burning off. I suspect that your car has a slight loss in compression from normal wear on the piston rings, and slightly dirty valve seats on the intake side. Any compression over 175psi is desirable, and you`re only +/- 6psi, which is not bad. Your car was likly 185-190psi from the factory.

Chances are, if the dirtbag crack addict that owned your car before was cheap and an idiot, he probably put no-name gas in the car (Olco gas is only for 1989 Dodge Caravan V6 Turbos :chuckle). This usually causes valve seats to gain some carbon buildup. That and you're sitting at 110,000+ KM in a car that I'm sure you touch the redline now and then on.

Try picking up a bottle of Seafoam, and run it through your break booster vacuum hose (or any vacuum hose right after the throttle, before the manifold turns into ports), use about half of the bottle. And dump the other half in your gas tank, not in the oil like it says on the bottle. Drive it for a day or two, and then try your compression test again. You should see some better results. :thumbsup

[krimsalt]

^^

Thanks for the suggestions, but the compression is perfect, considering the nozzle was hand spun into the cylinders. But i'm thinking the engine is not original with the car, after seeing bodyshop chalk marks all over it and almost 3mm carbon build up in the throttle body (no wonder the car would start to choke out after sitting a while at idle)...

[DanScarps]

^^

Thanks for the suggestions, but the compression is perfect, considering the nozzle was hand spun into the cylinders. But i'm thinking the engine is not original with the car, after seeing bodyshop chalk marks all over it and almost 3mm carbon build up in the throttle body (no wonder the car would start to choke out after sitting a while at idle)...

Exactly. With that much carbon buildup, I'd be running an entire bottle through the intake, maybe 1.5 bottles and half a bottle in a full gas tank.

[DanScarps]

Exactly. With that much carbon buildup, I'd be running an entire bottle through the intake, maybe 1.5 bottles and half a bottle in a full gas tank.

Sorry, I meant to also say that the compression is not perfect, they should all be reading out nearly identical. A few cylinders with lower compression is a sign of irregular carbon buildup or wear. That's why the Seafoam in your gas tank will help clean your ejectors, in case a few are slightly leaky.

[krimsalt]

Is it just me, or is it hard to accurately read oil levels on the dipstick because of the obscure design of the stick? I looked at it today to check up on it and at first thought i had no oil in the engine!!!

[Wes08M3]

^ yup! The pre 2010 dipstick was designed by a retard (probably a Ford design). They smartened up and put a regular, easily readable dipstick in the new models.

[krimsalt]

I might drill a small hole through the max level and the medium level of the dipstick, so it's easier to see the oil

[highlineMotors]

Is it just me, or is it hard to accurately read oil levels on the dipstick because of the obscure design of the stick? I looked at it today to check up on it and at first thought i had no oil in the engine!!!

You think that's bad. You should check out some of the Nissans. They're even worst!

[krimsalt]

Well there is no oil on the plugs anymore... The Crash cracked something and all the oil poured out of the car :(

[seek]

oil on plugs usually caused by worn valve cover gasket