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Analyze my R Plugs?

G

gottarollwithit

Cooks with motor oil
Joined
Aug 23, 2008
Location
nut Sac, Cali
Any thoughts?? I'm burning/losing a quart of oil every 500 mi or so. No huge puffs of smoke out the tailpipe. Using Bosch platinum iridium plugs. About 4k mi on these plugs.

There's black crud around the perimeter of the firing face. I assume that's from burning oil? However, the side electrode has this white ashy stuff on it. Usually i'd associate that with an overly lean mixture, but the car isn't throwing any codes and is pretty vacuum leak free.

Normal?? Or... almost normalish..??
 

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Turbo from the intake side was tight. No oil in the intercooler. Should I check the exhaust side?

Actually have this apart to do stem seals, but stopped because the plugs don't look super terrible and isn't blowing massive smoke.
 
Were the insulators and plug boots wet with oil? I know the valve cover seals around the spark plug tubes start to weep over time. My buddies S60 2.4T did that.
 
Exhaust side on the turbo won't blow oil into the combustion chamber, but it may be signs of a leaking seal.

Gwen's R was clean from the exhaust 90% of the time, even when it was leaking bad enough to drip oil from the exhaust manifold gasket. Stem seals took it from a quart in 1k to a half quart in 3k.
 
I'm going to put in a set of valve stem seals and see what happens. The motor has good compression across the cylinders. Think this is a head gasket or leaking valve, so it seems that stem seals are all that's left. If that doesn't fix it I guess the only thing left that it could be oil into the cylinders is the turbo
 
How gummed up is under the oil cap? Oil control rings could be plugged up. Maybe try running a few oil changes sooner with like BG's engine performance restore. Note- it is quite aggressive, read and follow the directions.
 
Replaced the PCV system a few months ago. Got plenty of vacuum at the oil fill hole. Oil cap is pretty dang clean. Old PCV was pretty clean when I replaced it. I don't think sludge is an issue.

However, I'm finding that oil loss/consumption is fairly inconsistent. Sometimes I can go 1 qt per 800mi.
 
I would have a leak down test done. Looking at plugs is fairly useless. I know that on mine (89K miles when I sold it, it was modified) I could go 4K miles without adding a drop of oil if I stayed off the boost or I could add a quart every 2K miles if I drove it hard.

Have a shop do some in-depth diagnosis on your engine before things get worse. The stock turbos can see 200K miles with proper care.
 
Was actually considering a leak down test, but i figured the time and effort required to do a leak down test would be the same as for valve stem seal replacement. To do a leak down, ya gotta pull the plugs and pull everything necessary to access the crank pulley through the front pass wheel well. Figured i'd have to put compressed air into the cylinders to do replace stem seals anyways... Would hear air in the coolant, oil cap, or intake/exhaust anyways....

Really just trying to determine whether these plugs look like i'm burning a little oil, or a LOT of oil. Alternatively, do you guys think these plugs look like this due to overly tight plug gapping?
 
Those plugs look like you're burning some oil, but not A LOT. Do they all look like that, or is it just one or two that are looking like that?

When I pull plugs out of cars that are consuming oil (at greater than 1L per 10000km ish) the plugs are extremely black. Way worse than what you've shown. So yes you're burning some oil, but the plugs don't tell me its burning massive amounts.

If you have some that are cleaner than others, I'd be looking at those cylinders
 
At the advice of one of the SS guys, I measured my spark plug gap. I found that gap was 0.024. Spec is 0.028". Some manufacurers go up to 0.030".

Think this overly tight spark gap could be enough to cause an incomplete burn? Maybe incomplete burn would cause the fouling on the plugs?? Or is that undeniably burned oil deposited on there?
 
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