The water pump on a 99 grand am is found where on the top or bottom?

it is not. just drain the cooling system, remove the belt, water pump pulley and water pump. its a total of 10 or less bolts and you can access the water pump from the top. :) happy repairing!

It's about in the center between the engine and radiator. To change it - keep the belt on (keeps tension on the pulley) and break loose each of the 4 bolts, but don't take them all the way off. - Remove belt - Separate the water pump from the housing. Sometimes a mallet works, but I had to get a flathead screwdriver and pry it out (just be careful not to mess up the mating surface for the gasket). - Pump should be out, scrape all the old gasket material away - Follow directions on new water pump for install - Also you can try putting a screwdriver against the bolt heads flat against the face of the pulley. - Press the neck area of a long stemmed screwdriver or prybar against the pulley, between 2 of the bolts (diagonally) - this will help hold the pulley steady. Then use your ratchet and socket to loosen (break) each of bolts. You will have to reposition the screwdriver for each bolt, but it works.

If you have the 2.4L motor it's driven off the timing chain. So you must remove the timing and exhaust. Book time is about 6.5 hours for a professional.