loud turbo

[IHateHacks]

And how do you think those air bubbles get into your cooling system? Here's a clue, you have to lose coolant to gain air in your cooling system.

My supra with a leaking head gasket never had coolant in the oil or oil in the coolant, never smoked ANY color out of the exhaust pipe. Before I replaced the head gasket I changed the radiator cap 2 times, the thermostat 2 times and it still overheated.

Did you remove the overflow hose from the radiator and plug the nipple for the overflow hose on the radiator? If not, then you just sucked outside fresh air into your tester causing a false negative reading. You have to remove the overflow hose from the radiator to correctly perform a block test.

Come on, replace that radiator cap if you think its bad or if its as old as the car. They are only like $10 from the dealer.

And what do you mean it held 6psi or only dropped 6psi on a pressure test? When you pressurize a cooling system, you should bring it up to 15psi and it shouldn't even lose 1 psi in the amount of time it takes to smoke a cigarette.