Another Cooling System Question

[JayW]

Over the years i've bought (and returned in some cases) water pumps with Plastic, Alloy & Steel impellers. Many years ago i replaced a water pump on a Fiat Panda which had a steel impeller, I use "had" in the context that it once existed but when i changed the pump the impeller accounted for 99% of the black silt in the system!

[barry badger]

Surely if the impeller is adrift the car would be overheating. Assuming the overheating warning system is functioning my moneys on the head gasket.
As an afterthought have you tried another rad cap and checked its sealing surface on the radiator?

[mat_fenwick]

Surely if the impeller is adrift the car would be overheating.

Locally, almost certainly yes. But with little or no circulation, the overheated coolant may not reach the warning lamp sensor. I too have come across a steel impeller which had disintegrated to nothing, but I suspect that was down to lack of antifreeze and hence corrosion inhibitors.

You could probably check for circulation by checking how quickly the radiator warms up after the thermostat opens.

[citronut]

the auto choke will not work if the coolant level is below a certain point, as the coolant cant get up into the pipes going to the auto choke wax stat, the first point to check is both the hoses to and from the auto choke are getting warm/hot,the other cause of the auto choke not operating is corrosion/fur build up in the spouts of the wax stat housing

regards malcolm

[kiwi]

It appears the water pump is at fault but who knows if that damage may have resulted in other damage inside the engine until I fix it.

Check done was basically with the rad cap off the water is not circulating/bubbling just expanding out of the radiator. Combined witht he carbie problem which I had forgooten over the last couple of years has resulted on a stuttering on hard /medium cornering under load. Increased Fuel consumption and the high unadjustable idle. My decision has been to decommission (the best least drastic description) this car after 6 years ownership and 60,000kms of driving it.