Mechanic really could not locate the origin of the leak but says the water pump needs to be replaced and says it's a lot of work and would cost $350. How can the origin of the leak be determined. He used a pump and raised the pressure on the radiator but that didn't reveal anything either. Please help.
It's probably the water pump, but if he has to take the timing belt off anyway, ask him if he can just put a new timing belt on for only the cost of the timing belt.
Water pumps should be replaced every 60K miles and the timing belt should be done at the same time. If your water pump hasn't been replaced in that long or longer I'd blame it having shaft play for your leak. The water pump is in the same area as the belts so it's definitely the most likely culprit.
