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Oil On One Spark Plug

11K views 8 replies 7 participants last post by  adumbrille 
#1 ·
I was changing my spark plugs today and I noticed that on my second plug that there was oil on it. The oil stain in the chamber was dry to the touch so I'm wondering if this was just an issue of overfilling during an oil change or if the seal was definitely going bad? The car runs smooth at idle and the new plugs fire up right away.

Should I just check it at my next oil change? Or just go ahead and replace the seal?
 
#2 ·
i noticed the same thing with my 3 recently except mine was in the first chamber. i poked around the forum and the consensus seemed to be one of those two options (overfill/seal). i went ahead and changed my seal just because i wanted to know how to do it, i'm a total noobie. when i pulled the plugs again to check everything had cleared up. it's like 30 bucks for the seals, so i guess it's no big loss if its just an overfill.
 
#4 ·
[quote author=dugger_8 link=topic=200549.msg4146353#msg4146353 date=1321017539]
Valve cover seal breaking down is the most likely culprit. Our 6 had the same thing and I just changed out my 3's at the same time to prevent it.
[/quote]

So just went the change my plugs today at 114k miles and my number two and four (from driver's side to passenger's side) spark plugs had oil on the threads. 2 was dripping with oil, 4 was just a touch, 1 and 3 were dry. All of the boots look fine and I don't see any oil in the tubes themselves.

Side note, checking the dip stick it's very slightly above max, but maybe a 1/16th of an inch.

So from what you're saying (and a couple of other threads as well) the valve cover gasket needs to be replaced, yes? Could the slight overfill cause this?

How hard is it to replace the gasket? Is it just removing the obvious bolts on the valve cover, remove the old gasket, install a new one and replace the cover? Anything else involved? Should I even bother replacing the spark plugs until whatever the issue is is fixed? Anything else I should check?
 
#5 ·
What you have indicates a leaking valve cover gasket. A slight over fill won't cause it to leak like that. It's probably been leaking for awhile for the one to be covered as you said. It's straight forward in replacement, remove the bolts, remove the cover, remove the gasket, replace gasket, you might need to put some grey gasket maker in the corner parts (where ever it does a bend), replace the cover, replace the bolts, hand tighten down. I can't remember the inch-pounds for torque but it's not very many.
 
#6 ·
When the engine gets hot, that leaky oil will get thin and go straight down onto that spark plug, and there will be little to no signs of the leaky oil because it runs like water @ operating temps, not gonna stick to the spark plug hole, it's gonna go straight down.. know what i'm sayin?
 
#8 ·
Thanks guys. I guess I'll take care of that at my next oil change..... should be next month. I'm assuming that since it's been leaking for some time that a little more won't kill anything, right? Do you guys have a price or p/n for the gasket?

Side note, while I went to look at my spark plugs I noticed the typical drip stains under my right motor mount. Touched it with my finger (lighter than one would use to move a turn signal) and my finger went through it. Replaced now.
 
#9 ·
[quote author=icspots link=topic=200549.msg4247708#msg4247708 date=1341863830]
Thanks guys. I guess I'll take care of that at my next oil change..... should be next month. I'm assuming that since it's been leaking for some time that a little more won't kill anything, right? Do you guys have a price or p/n for the gasket?
[/quote]

Use this walk-through I made on how to paint your valve cover. I have torque specs, pics, and the tightening sequence as well. The gaskets are $20 at a dealer or online.

http://www.mazda3forums.com/index.php?topic=209867.0
 
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