98 V70XC oil consumption and misfire

dmcfan · Post by **dmcfan** » 27 Apr 2015, 09:11

Trying to narrow down on my 98 V70XC where my oil is going and where my occasional misfire is coming from.

The symptoms are I am losing around .25 quart in driving about 500 miles. The motor has 114k miles on it and I use Syntec 5/30. Had the car inspected and no leaks, no smoke and no positive crankcase pressure. The hose after the turbo is a little wet but not where it would be causing that much loss in a week. Opened the plug/wire cover and it was completely dry. Where could this oil be going then if it is not coming out of the exhaust?

Here is the other issue that perhaps maybe related but not sure. Occasionally if I come to a stoplight from higher speeds 45-55 mph and idle for awhile the engine will sometimess have a very quick miss where you clearly feel it but no codes. Even less common is sometimes the miss becomes a stumble where the rpms drop a few hundred but recovers very quickly. To me that seems to happen when I have the ac/heat on only.

Other than that the car is running and performing well. The engine is pretty tight on the outside which is why I hope the oil is not a ring sticking but I would still think I would get smoke out the exhaust for anythjng internal. Perhaps I am wrong.

I have not had time to do a compression test yet. I have heard people have timing issues and the belt was recently done but that would only possibly cure the misfire and I am more concerned about the oil consumption.

I did switch to syntec when I bought it last year and the prior owner only used conventional but changed every 5k. This was owned by someone that went by the book at every interval and had all records going back to 98 as they were the original owner so it was not neglected.

Post by **abscate** » 27 Apr 2015, 09:23

My 1999 used 1 quart every 2000 miles since 30,000 when we bought it. Chasing that usage is very tough as it is so low. Just check it once a month, keep a quart in the car and enjoy life. Could be slight ring wear, valve guide seals, maybe a bit being burned in the turbo. It will cost much more to diagnose than the 1 quart of oil per year you are going to save by fixing.

draser · Post by **draser** » 27 Apr 2015, 10:42

Look at the plugs to see which is darker. If it's one particular cylinder and matches your misfire code you're on to something.

dmcfan · Post by **dmcfan** » 27 Apr 2015, 12:26

I will pull the plugs this week but I have no codes which is what is making this difficult to really find and that it is not consistent.

mika · Post by **mika** » 27 Apr 2015, 12:50

could be time for thicker oil (10w40, 15wX, ect, atleast for the summer) if your using 5w or 0w. Also, some new plug wires, distributor cap and rotor, ect should help with the shudder after getting off highway..