Oil cooler debris

[qcfarmer]

I am replacing the o-rings on a leaking oil cooler and I found plastic debris in the end cap. Any ideas where it could be coming from?

 

[David N]

I've always wanted to know too. Mine was the same way. Little black chunks?

I read somewhere it's part of a drain back valve or something in one end of the cooler. But my truck always started and ran fine. So I just cleaned it and let it be.

 

[qcfarmer]

More of a whitish grey. Truck sat for an entire year before I bought it so my mechanic thinks the coolant might have calcified.

I'm going to flush rad and go from there. There were only 4 passages in the cooler that weren't completely blocked and truck didn't run hot at all.

 

[David N]

Mine had little black bits of what I think were plastic. And yeah almost every one of my passages were clogged too. And it never ran hotter than any other truck.