I have a 2005 outback 3.0r. I recently did a new rad and thermostat because the rad cracked. Was haveing issues burping the system so took it to my local Subaru dealership to have them purge the system and they did and all was good until I drove the car an it was just pushing coolant through the overflow tank. So took it back and they performed a pressure test and a sniff test for exhaust gasses in the coolant and for a head gasket problem and both came back clear. But they are saying it’s internal head gasket issue and those tests will not pick up on that. My thinking is exhaust gasses that’s is pushing coolant means it is in the coolant and the sniff test should have found that?! Saying that the car now needs head gaskets. I’m wondering if there is any possible other culprit to my problem? Any and all help is much appreciated. Thankyou in advanced!!