thanks. for now, i'm telling myself it is carbon deposits. i am going to run some seafoam and see if that helps.draser wrote:Your mileage is about what I get unless I lean hard into it. Not sure yet what's going on with Volvo engine burning valves like that, it used to be that if valve clearance was too tight the valve would not fully close and will burn due to lack of cooling. On the carbon deposit theory, I opened up an engine at about your mileage and found hardly any carbon in the chamber and top of piston. It is true that I used injector cleaner but not overly. It seems there is something particular to these Volvo engines since a lot of people report burned valves. Like you're saying, if you want to hang on to this car and know/like to do some of the work youself I'd consider opening up this one - after confirming the low comp. of course.
fortunately, i find these motors relatively easy to work on. but...i definitely don't have the energy to pull the head right now. when i burned a valve on the 2000, the hole in the valve was as big as a pencil eraser. with that hole, the motor was basically running on 4 cylinders and idled very rough. right now, the 2005 idles very smooth.
have you had any experience dropping a scope into a cylinder to inspect the valves?