Overheating At Speed

[nhawan]

My 2001 Galaxy 1.9Tdi is overheating when driving at high speed on the motorway. It is perfectly fine in normal city driving. The temperature never goes above 90degrees in the city but on the motorway the temp starts to creep up when the engine is under constant load.

 

The water level and oil are ok. The radiator fans work. The heaters work fine.

The top radiator hose is warm. The bottom one is cold. Could this be the problem?

I suspect the thermostat, but a mechanic I took it to is adamant that its the water pump.....and wants

[NikpV]

not unusual for the pump impeller to shear off its shaft but I like you would think s

some gravity convection would occur. Suppose do the old trick of taking out the thermostat and popping it in some boiling water and seeing if it works would be your first job then suspect the pump.

[Guest mcyoungy]

Water pump sounds right.

 

 

[Guest Cepheus]

check your header tank. If the pump has gone then water wont be being pumped round the system and wont be being trickled back in to the header tank via the top hose. If water is still going in there then I would suspect pump is OK and thermostat is the issue as you thought.