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Matt
Matt, Mechanical Engineer
Category: Toyota
Satisfied Customers: 21859
Experience:  BEng hons Mech engineering, in auto industry 22 years
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My 2007 Toyota Avensis has a problem. The coolant leaks. Block

Customer Question

My 2007 Toyota Avensis has a problem. The coolant leaks. Block test has been done twice and was said that the head gasket is fine. Coolant looses through the radiator overflow hose. This happens only when the car goes over 60 mph. The radiator cap has been replaced but did not solve the problem.
Submitted: 2 years ago.
Category: Toyota
Expert:  Matt replied 2 years ago.
Hello

its possible that there's a fault with the water pump

So 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 If these are OK then remove the tank pressure cap and run the engine from cold with the heater set to full hot

As the engine starts to warm, squeeze the large hoses running to the radiator to help displace any air - all the time keeping an eye on the level in the header tank, making sure it doesn't drop below the minimum and open any bleed screws built into the top cooling hoses - closing them off as soon as they start to gush water

Once the engine is up to temperature the tank should be quite full. Switch the engine off and leave it to cool Then top up to the mark once its all cold and replace the cap

Expert:  Matt replied 2 years ago.
hi

do you still need help ?