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Matt
Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21599
Experience:  BEng hons Mech engineering, in auto industry 22 years
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No water returning to header tank

Resolved Question:

no water returning to header tank
Submitted: 1 year ago.
Category: Car
Expert:  Matt replied 1 year ago.
Hello As a very first check make sure the coolant level is correct / up to the mark on the tank,and if thats OK then replace the thermostat in the engine.Whilst the thermostat is being replaced you might as well also reverse flush the cooling circuit (remove top hose to rad and use a hosepipe to push water into the engine until you get clear water out of the radiator hose) and top up with 30-50% fresh antifreeze. Also check that the small diameter bleed hoses that run from the top of the radiator and the top of the engine aren't blocked as this allow the air to vent back to the header tank automatically.If you still have a problem then check that the water pump impeller / turbine isn't spinning on its shaft. You should be able to achieve this by removing the bottom hose from the engine and use a screwdriver or similar to feel for the water pump impeller blades, whilst your assistant turns the engine over by hand.If you can stop the impeller with slight pressure from the screwdriver the pump needs replacing. Also its possible the belt is slipping so its worth replacing its especially if the rubber ribs are cracked or it looks shiny on flat side of the belt - while its off check that the tensioner and other pulleys all spin freely the exception to this is the AC pump ( if fitted) I'd also suggest ensuring that you've got all the air out of the system as this sort of episode can leave pockets of air trapped and prevent the coolant from circulating properly. So check that the small hoses that run from the top of the engine and radiator that run back to the header / expansion tank are free flowing and not blocked
Customer: replied 1 year ago.

have done all this and still not getting water its got hot and when i take slacken the header cap all water overfills header tank ?

Expert:  Matt replied 1 year ago.
Hello OK this sounds like its gassing up, due to combustion gas getting into the water systemThe thing to try is a head gasket / block test kit as these take a coolant sample and analyse it for any signs of combustion gas - if present this would indicate the head gasket is on its way out http://www.uktools.com/block-tester-p-12508.html
Expert:  Matt replied 1 year ago.
Hi

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