looks like smoke coming from header tank

my P38 2.5 dse is overheating after a few mins running. I think it may be thermostat as everything else looks OK (fan running, no leaks etc.) BUT Checking the header bottle there is a return pipe from the radiator that feeds into the neck, and there is what appears to be smoke (exhaust fumes maybe ?) coming from that. Of course it may be just steam due to stuck thermostat and water boiling, it's difficult to tell, and I would have thought if it was exhaust the water system would have become highly pressurized, not just overheat. Before I panic what do you all think - warped head or head gasket gone ? Surely the symptoms would be more severe

nisbeam said:

my P38 2.5 dse is overheating after a few mins running. I think it may be thermostat as everything else looks OK (fan running, no leaks etc.) BUT Checking the header bottle there is a return pipe from the radiator that feeds into the neck, and there is what appears to be smoke (exhaust fumes maybe ?) coming from that. Of course it may be just steam due to stuck thermostat and water boiling, it's difficult to tell, and I would have thought if it was exhaust the water system would have become highly pressurized, not just overheat. Before I panic what do you all think - warped head or head gasket gone ? Surely the symptoms would be more severe

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That tube allows any air within the system to move from the top of the radiator into the header tank allowing coolant to flow out and replace it. It will be steam. Look at your thermostat or water pump ASAP.

If it were smoke, I reckon the pressure would blow something apart.

That's what I thought, thanks for the re-assurance. Will sort out the thermostat first - at least it's cheap compared to a water pump

nisbeam said:

That's what I thought, thanks for the re-assurance. Will sort out the thermostat first - at least it's cheap compared to a water pump

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If you do change the water pump have alook round maybe Island of Famous four can't remember but someone does one with a brass impellor. £48.00 but well worth it.

Thanks for the tip