My wife was about 150 miles from home and pulled off to get a soda. When she started the car and put it in gear, it started stumbling and misfiring under moderate acceleration. It idled fine and if she punched it, it ran smooth. The next day, I got in it and it ran the same way. I pulled the codes and got P0305, P0135 (twice), P1618, and P0705. I had never pulled the codes before so I'm assuming the 705 was from the time the car got stuck in winter mode. Shoving the shifter through its full range back and forth had solved that problem. I can't figure out what the 1618 is, but occasionally the ABS light comes on. Anyway, I pulled the cover on the coils to check them and the spark plugs. There was oil all over everything. I pulled each coil and rubber boot and #2, 4, and 5 had oil in the spark plug cavity. #2 was nearly full to the top of the hole! I have pics below. I soaked up all the oil and put it all back together. I fired it up and it still gave me the 0305 code. I thought about waiting until dark to see if there was sparking from cracked insulation but decided to swap the #4 and #5 coils. I figured that I would get a 0304 code if it was a bad coil. I started it up and it ran perfectly. No codes other than the O2 sensor code. I hate when something fixes itself but we'll wait and see. My question is: where is the oil coming from and how can a plug not be grounded out when completely submerged in oil?

 

I guess I should add that I've only had the car for 3 months and it has 170k miles on it.

 

That valve cover needs to be resealed cause it has o-rings around the spark plug wells. If ur not familiar with volvo, when u look at the valve cover it doesn't look normal! cause it's not, it's a volvo. It has almost 35 bolts in it and it hold down your cams.

I would take this to somebody who has done this before cause it's not all that simple. Pay a pro if u have to cause you have to redo the timing belt and it's tricky on that car, a lot trickier than normal. The valve covers not even a gasket, there's 5 o-rings for extra measure around the spark plug wells and the rest of the gasket is a very special silicone only made by Volvo. U also have to be extremely careful not to use too much of the silicone cause u could clog the oil ports that oil your cams. If u do that that Ur gonna have major issues.

Oil in those plug wells will make that car run like poop. Do the repair and get new spark plugs, and hopefully the coils aren't fried. I would clean them really good with brake clean and use dielectric grease when reinstalling then.

Also At that mileage replacing the o2 sensor is a good idea for all sorts of reasons. It could be helping the car misfire.

 

Who did the last oil change? To answer your question, oil dosent conduct electricity. The wet plug was causing the misfire. Identify and eliminate source of oil leak.
Don't throw money into O2 sensors and other random parts unless needed.
Curious as to the cars history with previous owner...
Good luck!!!!

 

That is a lot of oil in those oil wells. My guess is that the previous owner knew that was happening and that helped them decide to give the car up.

I have never taken a valve cover off but I don't think it's to hard if you are mechanically inclined. I'm not even sure you would have to take the timing belt off to remove that cover. Someone please let me/us know. If it has those seals on each splug well, that helps keep oil out of them, I'm sure they need to be replaced. Also, you may have a clogged PCV.

If you have a O2 sensor code, I would replace it.

 

Thanks for all the input. It was a one owner car before me but I bought from one of those dealers that hang around the auctions. All I know is some lady with kids and some sort of flower business owned it ( I found candy under the seats and almost a whole bag of potting soil dumped in the spare tire well ). I'm pretty mechanically inclined but since I don't know how long it took for that #2 hole to fill, I may just check it in a few weeks and see how much is in there. I probably need to change the timing belt anyway because I can't get the dealer who would have normally serviced the car to call me back with any history. They are 120 miles away and there's not much incentive for them to call. The car mainly stays in town and the interstate trip was not a normal occurrence.

 

This is probably completely ridiculous, but how is your seal from the oil fill cap to the filler neck?
I had the whole top of my head soaked in oil, and it was just a leaky cap. Over time, it can build up, and may have even found its way into the plug wells..just a thought. Best of luck!

 

That is possible but you would have to loose a lot of oil from the cap to do that. Also, the dealer's incentive to call you back would be to gain you as a customer. What is wrong with these people. I have one like that here. I don't use them either.

 

I just did a head gasket on that same car and it's a pain in the *** to take that valve cover off. Well it's not that bad, but getting it back together is hard. U have to b very careful. The timing belt has to come off the cams first otherwise u can break a very important machined section of the head. If u break it, there is no fix. U would need a new head. The timing belt will make ur cams pop out in a bad way if u don't take it off first. The cams have to come out completely. U have to clean both surfaces ( head and valve caver) Very good to ensure proper seal.

 

Update 8 days later. Yesterday I got another P0305. Since I had swapped coils, I didn't think the coil was the problem, which left either the wiring harness or the plug. I had pulled the plug last week and didn't really pay attention to the fact that it didn't have the electrode attached to the side of it. I had seen boat motor plugs similar to this and figured it just had weird plugs. I never pulled any of the other plugs. Yesterday, I figured I would swap plugs around (I won't spend $ unless I have to!) and realized they were just regular ol' plugs. Boy, did I feel stupid! $3.50 later, no code. I just hope when the electrode fell off, it didn't mess anything up.

 

Oh, by the way, I pulled the boot on the #2 well, which was full of oil last week, and it was dry. Who knows how long it took to fill up.