1997 740i bmw having overheating problems. i change thermo, and waterpump , but still overheating. allso i am experiencing heat problem inside the car . sometimes it blow hot then it stop blowing hot air in blow cool. overheat while driving. please help asap with this.

Overheating is a big issue, check the cylinders compression to make shure that combustion is not entering in the water system, this will also show if there is an exess pressuere in the hosses (but when overheating you will always have pressure). Also how is the radiator, do you still have water in it or you have to add all the time. There are some hoses at the back of the angine, they are for the heater core but they often leak.

Does the over heat occur at both low and high speeds (in traffic and on the road). If the over heat is at idle or in traffic only then I would suspect the fan clutch.