I have a 2007 XL7 AWD and the engine has been building up sludge about every 2500 miles. I have had the engine flushed every other month for the last 6 months. Have been changing the oil around 2500 miles and am using synthetic oil. About a week ago I noticed that the oil filler cap was very hard to turn and take off. When I finally did get it off I found a creamy whiteish substance around and in the cap. I was told that this is due to condensation build up and I need to replace the pcv valve from couple of people.
Monday, February 6th, 2012 AT 3:40 PM