2000 chevy blazer over heating?

The cause of this could be several things. I would first recommend you take it to a certified mechanic and get a free quote on how much it would cost to fix it. Now that the disclaimer has been made here is what I think it is. You overheating is due to many problems that have built up over the years. The ac coming on is not your problem in most cases but will use the motor more and put more strain on the motor which causes overheating at times.

Here is a list of what is most likely the problem:

Head gasket

Leak in radiator or hot water hose

water pump

I would also replace these items:

Temp gauge

Temp sensor

Temp Thermostat

If you have to keep adding water - this needs to be taken to a mechanic.

Hope this helps

man on a chevy it can be a couple of things. check your water pump. check your coolant and check your thermostat. coolant level should be at the middle point. check the color also. if its dark brown or something its time for something new. if its green you should be good. but really look at your water pump. usually when thats done you will see your coolant leaking and you dont know from where. it happens mostly when you turn the car on. its a little hole that it seeps out of thats causing your overflow to be empty. check that out.

Check for leaks, the thermostat, and fan. I doubt its the pump because the water is running down, so its circulating.

My money is on the thermostat or fan.

Re fill the reservoir, and fill your radiator with water/antifreeze mix.

You should have a mechanic check your thermostat.

crash the suv and collect insurance and buy a better car