Why is my 2000 Chevrolet venture overheating

Could be many things of course, not what you want to hear I know. I will assume the coolant level has been checked. I usually start with the thermostat because it's the most common and least expensive. If its leaking water/antifreeze, might be a hose or water pump. After that it could be low on oil or the cooling system clogged up,

Also I had this happen to me on a 2001 Intrepid. The A/C clutch went out and I lost air conditioning this past summer. It has this great/stupid design feature that when the A/C goes out it also kicks the relay and the cooling fans for the radiator also quit, causing the engine to overheat.

In my case over heating was caused by clocked catalytic converter! Cost me $180 to find this out! (I took it to the dealer and they diagnosed right) You may have same problem too! I changed myself and old catalytic converter tiny holes were totally melted and probably only 20% air was flowing.