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Oil on My Spark Plugs!

Help, Advice, Owners' Discussion and DIY Tutorials on Volvo XC90s. The XC90 proved to be very popular, and very good for Volvo's sales numbers, since its introduction in model year 2003 (North America).
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zerickso57
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Year and Model: 2004 XC90
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Oil on My Spark Plugs!

Post by zerickso57 » Sun Sep 09, 2018 6:04 pm

Hey All!

The last post I did helped me a ton, so a huge thanks to the guys that hit me back. I have the 2004 Volvo with the 2.5 T5. I was experiencing a misfire code and had to replace the ignition coils on cylinders 2 & 4. I also replaced all the spark plugs at that time. When I pulled up the plug from cylinder 2, the bottom half was covered in oil (oil isn't in the spark plug well). What can I do to diagnose and fix this problem?

I'm also experiencing a turbo issue, but I think (and hope) they are unrelated. Just felt like I needed to throw that out there.

Thanks in advance!!!



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SuperHerman
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Re: Oil on My Spark Plugs!

Post by SuperHerman » Mon Sep 10, 2018 7:57 pm

This is a tough one and will take a few steps to get to the problem.

Oil can be coming from three places: 1). From oil fill cap; 2) from valve cover and 3) up from the piston.

What does the top of piston #2 look like? Is it full of oil? What does spark plug look like reative to others?

You need to clean up the outer valve cover really well. Also clean up piston #2 spark plug well. Then run the car for a few hundred miles and report back.

It is possible your valve cover o-ring is failing allowing oil entry. This is better than having the other possibility of ring, valve stem seal and/or valve issues. Those two items are not good. I have seen that sloppy oil fills could also be the cause.

Run through the steps and see what you find. You could do a compression and leak down test if you are anxious and have the tools.



zerickso57
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Joined: Tue Aug 14, 2018 11:16 am
Year and Model: 2004 XC90
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Re: Oil on My Spark Plugs!

Post by zerickso57 » Thu Sep 13, 2018 8:32 am

Thank you, sir! This gives me a great start. I'll be working on the car while Hurricane Florence beats down on us. Will report back in a few days.



ChrisD
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Re: Oil on My Spark Plugs!

Post by ChrisD » Sat Sep 15, 2018 10:42 am

I recently lost a turbo and had oil on all spark plugs. FYI. The Turbo was running fine right up until it instantly failed and blocked the highway with smook. The other day I also had an xc90 with plug number 4 fouled, all the others were fine. Stuck valve. Changed the engine, ya I know , overkill.

AND the other day I had an older XC70 that the plugs all loosened up because someone used neversize on the threads. Oil on some of the plugs. Don't use neversieze on plugs, on any Volvo anyways.

A compression test is a good start as mentioned. The blocks, even if the valves have broken, are very robust and can be cleaned unless the damage is (IMO) massive. MY BET, is a broken valve spring or a stuck valve, both easy to fix by any reputable Volvo experienced machine shop.

What you didn't mention is : Did changing the plugs solve the misfire issue? At least for a time? The coils almost never fail, I suspect the coils were un-necessarily changed. I would have done the same,...did you try swapping the coils around? Were the coil connections dirty? How much of the plastic wire loom material is left, they degrade and are easily flake off? Another common issue is if you replace the wire loom tubing with electricial tape, if you wrap the coil wires too tightly they can cross talk.

My guess is poor oil changes, causing the small passageways in the valve cover to stick a valve, and easy fix. You can get a really nice "head" gasket set and new head bolts from Fel-Pro / Permatex includes new valve seals as well. Do you have a dual VVT system? Find someone to retime the engine, not a big deal. Be advised fixing the head will put your costs over the book value, so if the vehicle gets totaled youll never recoup the cost of the repair. BUT if that's all that's wrong this repair will IMO outlast the rest of the engine. If you change everything, belts, water pump, crank seals,... etc at the same time


CHECK your PCV system!!!!!! It is the root of all evil in older Volvos.


POST what you find and how it was repaired!!!! It means a lot to those of use trying to keep our rides running.



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