1999 xcv70 What is that on the Cylinder walls

flyingd · Post by **flyingd** » 10 Nov 2014, 22:19

I lost compression in #2 cylinder and so I took a bore scope and looked inside. It almost looks like the walls have rust on them.

What do you think it is? I am concerned/perplexed

Post by **FLXC90** » 11 Nov 2014, 09:14

I guess the first question is, how do the others look? numbers from your compression check?
Without better color/lighting I would say if it's not rust it's carbon deposits. Is that the edge of the piston top? picture down through plug hole? Aluminum piston won't rust, iron sleeve will. If you burned a valve, bits of it may have gotten loose in there. Is it just on that area of the cylinder, or all around the circumference?
How long have you had the car? Head gasket ever been done? Long period unused? I had a van that sat after losing a head gasket, and developed rust in a cylinder.( but it sat for about 2 years) Scored the walls pretty badly. Rust on cylinder walls and rings don't make great combo.

If it is carbon, maybe a dose of sea foam and let it sit a day or so to dissolve the deposits, the run it to purge?

Post by **Ozark Lee** » 12 Nov 2014, 21:37

Of more concern to me are the scratch marks through the discoloration than the discoloration itself.

...Lee

Post by **FLXC90** » 13 Nov 2014, 20:56

https://www.matthewsvolvosite.com/forums ... =1&t=66757 he used your idea of borescoping, found a burnt exhaust valve. That may be scoring on your cylinder, if a valve disintegrated, pieces may have gotten in the ring/cylinder. Does your scope flex to where you can view the valves? If it doesn't have a control to turn, some sting around the base of the lens may work. GENTLY, maybe test before you put it down the hole.