Hi,

After replacing timing belt, water pump and thermostat on my A4 V6 3.0L, the "coolant temperature too high light" is on. The coolant temperature gauge on the instrument panel is normal (at middle). It seems the coolant system is not circulating enough coolant through. The radiator is not very hot. Could that be a water pump or thermostat problem? How to check if the water pump is working correctly? Is there an easy way to check the thermostat without removing it from the car?

Thanks in advance.
Ben

 

Maybe the water pump? did you do your thermostat with the belt?

 

Yes, I replaced both thermostat and water pump. How could the new pump fails? Is there a way to determine the water pump is bad? Actaully I bought the pump from the dealer. It is a remanufactured one.

 

Did you place the bleed hole in the thermostat to the top? And, double check that you bled ALL the air out. Open all the bleeds and check for water.

 

I followed the procedure in the Bentley manual. I opened the bleed holess on both radiator (on the metal pipe connected to the thermostat) heater hose, until coolant came out.

Do you know a way to check water pump is woking? I remember there was post describing how to do this a while back, but I can not find it now.

 

Not sure on these cars.. you could warm the car up and check that both hoses are warm - actually one should be hot, the other warm.

 

The upper hose (coolant going into radiator) is hot ( not as hot as engine block). The lower hose (out of radiator) is cold (or warm). Only the end of this hose close to the thermostat is hot. Could this be a thermostat problem? If the thermostat is stuck close, how could both sides of the valve are hot? Thanks.