2002 Chevrolet Blazer overheats/no heat?

[mustangfreakz]

This problem started about a month ago, it started with the heater blowing cold air, now just yesterday the temp runs in the red after about ten minutes. Strange, but in town it does not overheat, just on the freeway or high speeds... my mechanic said to replace the theromstat?

 

[pbleek]

overheating with no heat usually means your water pump is bad, its not circulating the coolant. Thermostat stuck closed would give you lots of heat, thermostat stuck open would make your engine run cooler than normal.

 

[davidlill]

Air lock in Cooling system

 

[vincentmb615]

yea thermostat is a cheap piece to change if its stuck open itll throw no heat and temp gauge way up if you change it and its still choppy check into a coolant flush or a heater core good luck

 

[junkyardbug1]

I think it is your thermostat , take it out and drive it around a while and see if the heating problem is gone if it is then buy a new one, if not your heater core is bad..is your window steaming up alot?

 

[tronary]

You need to see a RADIATOR SHOP I believe you have a partially plugged radiator. Thermostats do not act this way and NEVER do a radiator flush. A flush is useless and a money maker for the shop.