Purchased a new oil cooler for my 502, noticed it has some sort of debris in it that is rattling inside. I've pulled all the plugs, and blew air through, can't seem to get it out. Not sure if it's in the power steering circuit or oil circuit, but don't think I want to run it............. Anyone seen/heard this before?

Doesn't sound right to me. I'd return the cooler. Mine are solid enough to drive over!

It's solid, I just have something in it that won't come out with compressed air.......

If you can't verify what it is, it's not worth the chance.

I had a brand new over the GM counter 5.7L truck engine that had a head not drilled/tapped for spark plugs. No schit !

Things happen, as much as we hate them too.

Try flushing it from each port with a garden hose hooked up to it. Water > air

I have seen welding slag come out of heater cores and a/c condensors..........

I certainly wouldn't trust it. Send it back and get another one.
Eddie

Sent it back. Manufacturer took a look at it, and said that it probably is a piece of braze in between the cooler tubes and would never come out. I stated i'm not comfortable installing this on my boat. I requested another be built and sent to me that was not contaminated. Sounds like that's the new plan now.

I'm curious, anyone here have a customer cooler built before? If so, who did you use?