Volvo EC15B expanding tracks

[Muz]

Blowing out steam from the expansion tank, at which time the water starts to bubble - so deffo overheating. Engine keeps on running OK as I have caught it when it starts to steam (thus far). SWitch off, leave to simmer for c. 20 minutes, top up water again and then might get another 6-8 minutes before steam restarts.

Squeal from what I thought was the belt when the engine is running has been traced to the water pump - almost exactly the same noise as we get from a failing water pump in our boat engines (which is sadly all too common)

Thermostat seems to work OK as per maintenance/repair/service manual specs and water pump is rough as the proverbial. Only time will tell if my diagnosis (of this issue) is correct.

Muz - can you please point me to where the solenoids might be located?

Many thanks again

It should shut down automatically if the sensors and ECU are working correctly .. I'd check the radiator is clear , I mean totally see through clean, you need to pop out the oil cooler to make sure its crystal clean everywhere, they choke up real easy and that would cause your problem, if it isnt a failed pump, or an air lock to the heater matrix not allowing the pump to circulate

will be a post elsewhere here about the solenoid positions, have a search