- Jul 5, 2019
- Marysville, OH
So I am in the middle of doing all the cooling hoses, fixing egr system, oil leaks, injector clean, and new alternator install. I decide to pull the plugs to see if I had any valve cover leaks and two of the front 3 plugs had these deposits on them. I thought maybe coolant but it hasn't ever lost any, the truck runs fine with only P401 codes, never given me any issues engine wise in the last 20K of my ownership(has 220K). Any ideas what these off white deposits may be? Anyone ever see these before?