200tdi coolant issues, help

Erm any help much appreciated, but I fear I may already know the answer.

I have a 90 converted to a discovery 200tdi, and it seems as tho my coolant is pressurising, although it is running at a steady 90ish degrees.

It's fine under normal driving but if pushing hard it will force coolant out the expansion tank, but the temp remains steady,

I did change the thermostat before this started happening, and I did test the stat before fitting, could it be that I have an air lock? Or is it something more sinister?

Thanks in advanced

Head gasket failure is a possibility !!!

Whats the cold level in the coolant header tank!
If its correct ie half full have you tried a new tank cap?

It's still the original td expansion tank, the valve in the cap seems free enough.

Will check coolant levels today,

Other than the coolant issue the engine is running fine, pulls well

The valve in the cap may be free, but is it releasing pressure to soon, hence the coolant loss?
What rad/fan set up have you got, how old is the rad?
When you say 90 ish degrees what are you measuring temp with?
I have 2 200 and both run at an almost constant 88/92 degc even when thrashed good and hard, both have pretty accurate capiliary type gauges

The rad is prob not at it's best tbh. It's running an electric fan, controlled via a switch.

The gauge is a smiths gauge with matched sender so should be reading ok.

Never thought about the valve being too free, kind of obvious now tho.

If it is happening at low rpms you might be able to see the steam pulse if it is a head leak on one cylinder. Just soemthing to look for

rad could be blocked had this on cars in the past had a 2.0 petrol montego chucking water out of the cap when pushed hard,rad was the culprit may be worth getting a sniff or compression test done to rule out HGF

Well found the cause, well and truly buggered head gasket

Mrtea said:

Well found the cause, well and truly buggered head gasket

Click to expand...

well, the bright side, it isn't a particularly hard engine to do the head gasket job on.