Nissan Patrol 3.2 diesel overheating / radiator or head gasket? Anybody got the right answer?

Question

The water in my radiator is pressurising and looking like white foam.

The thermostat has been removed already.

The radiator cap has been replaced.

After releasing the pressure the temp drops and the motor runs normal for a lot of miles.

Revving the engine with the rad cap off the water level drops but when the accelerator is released the water/ foam gushes over the top of the rad.

Answer 1

you need to have a leak down test done it is a test that cost a lot more on a diesel if it dose not show up thru radiator you might have to remove sump to see if water is comeing out of cylinder liners it might sound of but diesels get air bubbles that sit along the liners and implode whitch removes a tiny bit of the liner eventuly you get a leak if you have had been adding anti rust it hase a wetting ajent and will stop the problem dont worry about water lowering as engine rpms rise it is just proveing the water pump works p.s. dont run engine with out thermostat it is a old idea for petrol engines diesels need to run at operating temp to stop premature wear

Answer 2

Cracked head or blown head gasket, one of the two.