2000 Buick lesabre overheating

That sounds like your water pump is bad.

Also, did you "bleed" the system? There are bleeder screws. One in particular by the thermostat housing.

With the car running, open that screw and let the air bubbles come out of there until it's just plain coolant/water mix.

Don't forget to put a drain pan under there! If you're still not sure where this screw is at, watch a You Tube video on how to bleed your cooling system on 2000 LeSabre. I bet they have one

Also, let's check the intake manifold as a precaution. Can I assume the car is running good otherwise? The overflow is full, but not overfilled and oil mixed in? No water/coolant in the oil?

Electric fans coming on?

I also replaced the waterpump and elbows. The car was running fine until i ran over a bump in the road. The radiator was low. I added two bottles of 50/50 antifreeze. After bleeding the system the car is running normal temp between 190 and 212. When driving the temp goes up around 220 to 240. The fans are coming on. The replacement radiator was used and doesn't have the temp sensor.

I think THAT is your problem right there! The temp sensor sends the correct info to the gauge.

There are at least 2 temp sensors

Well, I couldn't upload the pic.