Guys I am confused with the following issue .
When I drive the Terracan it pushes air into the expansion bottle along with coolant .There is no overheating on the vehicle and it reaches normal temperature.The expansion bottle just has a press on cap which when driven appears to be pushed off by the pressure build up.
I have done a chemical test for the head gasket which comes back as normal.
Heater matrix changed
Rad cap changed
Can’t think of anything else .
I’m pretty sure it’s the head gasket but wanted to throw it open before I start to dismantle it .