My 2000 Chevy silverado 5.3 keeps overheating, when I turn heater on it will cool down, whats wrong

Question

My 2000 Chevy silverado 5.3 keeps overheating, when I turn heater on it will cool down, whats wrong

Answer 1

The Radiator is not flowing enough coolant thru it and when you turn the heater on the heat is being relieved thru the heater to cool the engine. Suggest the Radiator needs to be cleaned out at a Radiator Shop.

Answer 2

It is likely time to recycle the vehicle. AutoOnInfo.net's detailed reliability and durability studies suggest that 7-year-old Chevrolet is as troublesome to own as a 34-year-old Toyota and a 48-year-old Honda. Your vehicle is at least 8 years old and I haven't seen any 50+-year-old Hondas on the highway, although I have seen an occasional 30+-year-old Toyota.

When you do recycle it, it's probably wise to take a look at a V8 Toyota Tundra, which has an AutoOnInfo.net Reliability Grade of B, versus a D for the 2-wheel-drive Silverado and an F for the 4-wheel-drive Silverado.

Answer 3

see if your radiator fan is working. thats probably what it is. as soon as it oveeer heats ,,,raise the hood and look

Answer 4

I'd bet on a restricted radiator.A heater is nothing more than a small radiator that puts the hot air inside the truck. when you remove radiator to have cleaned or replaced.... replace the thermostat. you will be better off in the long run.

Answer 5

I would not get rid of it just yet like the above person mentioned, I had a 2001 chevy with the 5.3 and never had a problem. They are really really great trucks! My friend is a mechanic for chevy and he said check to see if the anti freeze was changed from the red to green or vice versa. It was something chevy did a few years back and it can cause all kinds of problems with the radiator, hoses, and over heating because the change could have caused corrosive reactions in the motor. Check with a chevy mechanic because I am sure they will have seen this problem and they will know exactly how to deal with it.

Answer 6

most of the time its the thermostat but it also could be you need to have the radiator flushed out best you have it dip at a radiator shop about 50 bucks last time i had it done but try the thermostat 10 bucks

Answer 7

if the temp goes down with the heater on, your radiator is plugged up, thermostat is bad or the head gaskets are on their way out.  the heater lines are attached to the top end of the motor in most cars and truck 'cause thats where the heat is...  the fan clutch could be bad but if your cooling off that much more with the heater on, the heater core is doing the job of the radiator.... does this truck have a alot of miles on it ?  have you ever flushed it out or replaced the water pump ? it sounds like its time to do some need servicing on the cooling system if it has over 80,000 on it. if its well over 100,000, it could be all of the above !   good luck...  

Answer 8

When did you last flush the radiator and change the antifreeze?

Either your radiator is clogged or the thermostat has gone bad.  

Take it to your local mechanic, tell them the problem, and if the thermostat needs to be replaced, ask them to backflush the radiator and put in new antifreeze while they're at it.  That will save you problems in the future.

Answer 9

It needs a new heater coil or core or whatever they call it.