I've got a 99 Express Van 3500 with the 5.7 engine and about 56k on the clock. Truck has always been maintained well, oil changes, etc.
Using Dexcool Coolant....
Recently while checking fluids and such it was low on coolant, the overflow was empty and the rad was maybe 1/4 low.....I have never seen any obvious leaks and the truck never lost coolant before, at least not this fast....
Then I noticed an oily residue on the inside of the radiator cap, not alot, but it was there and looked like dirty oil....This is also a recent development....
What do these symptoms suggest to you guys ???
TIA
Jeff