2.2 engine suddenly overheating

Defender 110 hi cap 64 plate 2.2tdci ,runs for days then with out warning temp gauge rises to red , engine goes into limp home mode ,when you lift bonnet header tank has emptied through valve on cap (new cap & new thermostat fitted) when refilled with coolant bubbles can be seen entering header tank until engine reaches normal running temperature. Runs for 3or 4 days then problem starts again .l think head or gasket is at fault ,but before I start pulling the engine to bits is there any way to check the egr cooler for leakage in to the cooling system without removing it. Also are the 2.2 engines fitted a overheating sensor to put the engine into limp home mode ,when this engine was used by Ford it had a sensor fitted to the back of the engine to cut out the engine if overheating occurred

I take it that due to the lack of replies no one has any real knowledge of faults with the 2.2 puma engine,since I last posted I have by passed the egr cooler only difference to the fault is ,it takes longer to get warm air through the heater .so I will test the water pump but I think this will be grasping at straws, if water pump is ok cylinder head will be removed.

HI - I have the same problem with my 2.2 Puma. Did you redo the head gasket in the end?

Go straight for the egr cooler first. It'll give all the symptoms of a blown gasket.. Even gasses coming into the coolant tank.
For god sake don't drive it at the risk of blowing the gasket. These heads are a matched set and if it's damaged your in for it with costs..
A simple way is to do a bypass on the egr cooling circuit and if the symptoms stop along with steam from the exhaust and gasses in the coolant tank it could well be the egr cooler. If it continues, do a compression test.