I have a Nissan FB13 Supersaloon.
The car started having radiator problems when the radiator was blocked. After repairing the radiator the engine started building pressure and you could see bubbles from the radiator cap within 3 minutes of starting the engine.
I then took the head for repair suspecting that it could have warped. I bought a 3 mm thicker head gasket but still the problem persisted. The head has been skimmed 2 to 3 times. The guys who serviced the head said they did every tests on the head including pressure test and they say the head is 100% perfect.
What could be the problem?