At the last CCV just pulling off my trailer and heading along to the first section my trials motor went above its normal running temperature, it normally sits pretty much on 88c, but it climbed to 95c before the thermostat opened. When I started to poke about their was an airlock in the cooling system, I topped up and bled the air and it went back to normal with the thermostat opening at 88c. I pressure tested the cooling system and found a couple of leaks on a couple of hoses, but a coolant block test showed exhaust gasses in the coolant. I have now done a compression test both cold and hot but these were all good? Reading online this seems to imply that it will be a cracked block rather than just a head gasket is this always the case?
Cheers
Luke