I had the system pressurized and they found no leaks. They pressurized the radiator, and fill bottle, and found nothing. I get milky gunk on oil cap. I'm in Long Island NY, by the way. No gunk in fill bottle. Dip stick is clean. Jeep runs fantastic. Doesn't overheat unless running low on coolant. I did do the block test today with OEM block tester and it turned yellow both times. I'm probably going to have to get the head gasket repaired.