Hi

Read a lot on the forum about this problem. This is my first post divided into 2 parts:

1/ Had coolant dripping from under the car at the AC condenser drain hole/pipe. Isolated the problem to the heater system and blocked the 2 pipes feeding this system off. Now it can either be the core itself or the heater bypass valve as I picked up from the postings. Q: Is there a easy way to test which one is the problem?

2/ There is a brown sludge in the water expansion tank. Repair shop told me that oil is leaking from the oil cooler pipes into the radiator. I read on this forum that the problem might be the head gasket. There's no sign of any water in the oil. Q: How do you determine which one is the problem?

Thanks in advance.

Great forum!