Did you check the water pump?

You are right. The problem of water pump could be a possible reason. But the machanic said he thought it was OK.

You said that the coolant is leaking everyday?

So it could be the water pump or some pipes that connect to it.

Suggest that you try another garage.

may the coolant temperature sensor is worn out, and also there is usually one or two relay switch that controls raditor fans. after these years, the temp. sensor and relay switch may be old and worn out. may be change them will do some help.

regarding coolant leak, u may want to check if coolant goes into your engine oil, (can do this by oil analysis, cost about $22). if no leak into engine oil, then check the water pump, hoses(make sure all connections are dry and tight), relay switch, coolant temp. sensor, themostat(make sure use oem product, not aftermarket product).

if there is coolant in engine oil, this usually the cylinder head gasket is about broken. this will cost big money. may be better to get rid of this car.

I went to the Toyota dealer to check my car. They found the leaking coolant in cylindar 3, the possible answer is the head gasket is bad. I am planing to change it since my car is still under the warranty. Thanks all.