Oil in radiator, but no water in oil????

[treveiger]

I have a 1969 chevy c20 with a 307 and flushed the radiator to switch out the old pump(it started to leak) and found what looks to be oil in my radiator but checked my oil but it still looks good no antifreeze in it or anything, what could this be from? Theres not much oil in the radiator but just kinda threw me off guard. Any help would be great!
Thanks in advance.

[chisler]

Is the truck auto.... maybe cooling line to the rad inside.

[raycow]

+1. It could be the transmission cooler if the radiator has one.

Ray

[mdwilf]

X3 - if it's auto, it could be trans fluid - & a friend of mine found out the hard way it'll toast your tranny - spent almost 2k on tranny rebuild, then the rad went out. New rad was defective & it ruined tranny. Of course he had the rad put in a different place, so guess who got to pay for the 2nd rebuild?? Him.

Also, it's possible to get oil in antifreeze, but not other way.