[Airjer_]

Engine size would help?

If its the old style 2.2 than it takes about 20 minutes (book time is probably around an hour)

If its a 2.4 than he is correct. Once the exhaust manifold, front timing chain cover, and the timing chain tensioner are removed the water pump/housing assembly can be removed. Have him through in a t-stat while he is in there. The pipe the t-stat is in bolts to the housing I'm sure he would only charge you for just the part and no additional labor.