After having a new radiator i still suspect the thermostat has gone because the temp gauge rarley shows above 70 and drops to 50 very quick.
so i do the thermostat test.
bottom rad hose gets warm first. top hose takes 10min to warm.
with a bit of revs the temp gauge reaches 88ish and the fans come on.
then the pipe from the thermostat to the water/exhaust gas heat exchanger for the EGR system BURST
spewing coolant all over the place.
I think the cooling system was not working till the radiator was replaced.
I think the thermostat is stuck part way open, hence taking so long to warm up and the gauge going up and down.
when the rad was replaced coolant started to flow through the system and when the thermostat reached temp it opened fully causing the EGR pipe( which is covered in oil and probably perished by it) to burst.
Does this sound plausible.?
Could there be another reason?