My 1998 chevy cavalier runs hot in slow traffic.

So did you check the gauge and the sending unit ?
Either component could be faulty.

Quote "and no coolant in my engine." Put some in

hi chris does your car have electric fan or viscous. u say it heats up in traffic.If its electric fan can u here when it comes on.

sounds like it's time to take it to the shop and change head gasket if head is still good ! every time it gets hot it warps it, prob. need new head too !

The water pump is all i can think of

Yes it does have a electric fan, mine went out on my 2003 and I just changed the electric motor itself. Autozone offered the entire fan with motor or they offered just the motor. I chose to replace the motor only because I knew the fan blades and housing was fine. I had to drop the fan down and take out the entire assembly from the bottom but overall the process was a 3 out of 10 on the difficulty.

This is a Classic Sign of a Dead Waterpump.

I am a mechanic in a shop in my area and replacing a water pump on your car would not cost that much money. I checked the prices of a water pump and thermostat and I would not charge more than $250 for the job. I pays 1.5 hours labor to replace the pump. I hope this is helpful.

if car doesn't run hot with no thermostat...you may be air-locking system when installing thermostat. I always fill the engine block up to the thermostat housing to make sure that engine is full of fluid ..then install thermostat...spring facing down..thenfill radiator making sure car is running so as not to air lock system ...run until top hose gets warm ,showing that your thermostat opened

Try to remove the thermostat and run it without it. If it does not overheat then you just have a defective one if you have replaced it. Or ou accidentally put it in backwards. It will not hurt anything.