550 oily sludge in coolant

[bdog2]

Hi all, Removed my radiator cap and there is an oily sludge in coolant. Pulled hose from block at top of oil cooler and coolant appeared to be clean. Don't appear to have any water or coolant in oil. Have gaskets and orings to rebuild oil cooler. Does it sound like oil cooler is failing. Can I pop top of oil cooler and pull it out and tell if it has had it and need to replace entire thing. Anyone experienced this or any suggestions/advice appreciated. Thanks

[LeonardL]

As far as I know there is no real way to check those coolers. They are notorious for leaking oil into the coolant however and I would change it out. Some of these other guys may know a way to check them but I always just replaced the darn things and got it over with.