Ok I checked my radiator overflow tank today, and on the bottom and sides, was this residue. It was light gray and felt waxy. This one definitely stumped me. There was none in the radiator because I drained it to check. Then since I was at it, I flushed my radiator. Hopefully this won't appear again. Anybody have any ideas as to what it is?

TIA

Mike

 

sounds like the beginning of a failing headgasket. did you notice any oily swirls in your coolant when you drained it?

 

No, there wasn't any oil in the radiator fluid. The overflow tank was slightly grimy though. I had a warped head last summer, but I got it resurfaced and a new headgasket on. Maybe it's residue left from then?

 

Anyone else? Is this stuff leftover from last year?