99 Infiniti i30, oil in spark plug hole?

nospam.auto · 2008-11-17T22:42:33+00:00

I have a 99 Infiniti with about 70k miles. I was replacing the spark plugs over the weekend and noticed the 1st one has oils in it. The rest 5 of them looks clean. Called one place, the owner said probably the O ring around the valve opening needs to be replaced. About an hour of work, $100 plus parts. Of course he said it all depends on what they see when they open it up.. Called a different place, the guy said probably the valve tubes needs to be replaced, and all 6 is about $400-$500, kind of a big job since they need to open up the valve cover, etc. pretty involved as he puts it. Is this something that I can do? Searching online for "oil in spark plug hole", I found quotes saying "it's simple and easy fix". but looking at my Hays repair manual and the online instructions, it seems more complicated than what I am comfortable with. (replacing the spark plugs is about the most involved fix I've done, and all 6 took about 2 hours). How serious is this problem? I have one additional issue regarding this Infiniti which I recently bought. Comparing to my 99 maxima SE, the Infiniti has a very subtle and short vibration when I accelerate from a stop, for the 1st 1 or 2 seconds. On the maxima the engine power seems very focused, acceleration is smooth. On the infiniti, maybe around 50% of the time, there's a very short humming type of vibration initially, and goes away very quickly. The power isn't as focused as my maxima. On highway driving, the Infiniti makes a subtle noise. Sounds like "heheheheheh", say it as fast as you can and that's what it sounds like. Again it's very sutble, I notice it, but my wife doesn't notice either of the issue above when she sits in the passenger side. Initially I thought it was the wheels that may be out of balance. I did a road-force balance on a GSP 9700 on all 4 wheels, but the sound seems to remain. I did: - replaced engine oil with 5W-30 synthetic oil - replaced all 6 spark plug with NCG OEM plugs. - balanced all 4 wheels could the...

Nov 17, 2008 24 Replies

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nospam.auto 17 years ago

I had the exact same heart attack moment when I bought the infiniti and was reading the owner's manual. What, 5w30, I thoughted my nissan wanted 10w30. took out the Nissan manual and was like, What? 5w30? why the hell have I been using 10w30 all these time?

I might have mis interpreted the information in the manual back then. it says if temp is above 32, 10w30 can also be used. I read it as

10w30 is preferred for temperature above 32. I am in the san francisco bay area so most of the time it's ok.

Is 5w30 a thinner type than 10w30? If the temperature is warm, will I get better protection for the engine for using 10w30?

Raymond

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nospam.auto 17 years ago

Will driving on the highway for a long time (say 4 or more hours) put more stress on the car than a shorter trip (say 30 min to 1 hour)?

While highway driving is better for the car than city driving, I think trips longer than 1 or 2 hours puts a different kind of stress on the car. I sometimes feel my car drives slightly better after a few days of normal commute (15 minutes on the highway) after a long trip, just like me when I need to recover for a day or two after a long trip. ;) I can't think of a good reason why it would, being that everything is metal and mechanical, but I thougt it did.

Raymond

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Nate Nagel 17 years ago

Yes and no.

The 30 is the important number, that's the viscosity when hot. Truth is, "better" protection comes from a lot of factors, and a viscosity of "30" covers a lot of ground. So one would assume that a 5W30 might be slightly thinner than a 10W30 when hot, but it might not be. e.g. a synthetic 5W30 might be formulated to be thicker when hot than a conventional 10W30 because the synthetic is more temperature stable and requires fewer VI additives... it's a complicated subject and there are no easy answers.

Best thing to do is simply use a quality motor oil that meets the mfgrs. specs... if you want to second guess the mfgr, you have a big learning curve ahead of you and you will find then that not all oil mfgrs. publish all the specs that you need to make decisions.

Note that that advice is only good for modern engines that don't require lots of anti-wear additives (don't have flat tappet cams) if you have an older car with flat tappets, all the above does not apply - you *do* need to do some research to find an oil that won't wipe your cam.

nate

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Steve 17 years ago

Not unless the car is a hopeless POS with an inadequate cooling system or something. The longer the trip, the better.

Besides, 4 hours hardly qualifies as a "long trip." Hell, I used to jump in my '73 Satellite and drive 12-14 hours at a time except for gas, food, and restroom breaks.

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