1998 Blazer Heating problem

My heater used to work just fine and then all of a sudden, it takes a real long time to heat up. Like it only heats up while I'm on the freeway. Any ideas???????????????????????????????

If you are not overheating, then your heater core is blocked. Get the system flushed and refilled and specifically tell them to check the heater core for flow. If you have Dexcool, you are either getting air in the system (from a bad rad cap) or the Dexcool has outlived its life and is getting gummy. If the truck is running cold as inidicated by the temp guage, your thermostat is likely stuck open.

My heater used to work just fine and then all of a sudden, it takes a real long time to heat up. Like it only heats up while I'm on the freeway. Any ideas???????????????????????????????

What does the temperature read on the temp gauge?

1/4 1/2?

Thanks for replying fellas. The temp sits at a lil below half.

sounds like the temp is within range, is your radiator topped off with coolant...also I would look towards possible air in your system, mainly in your hearter core itself...if you are getting heat at highway speeds I wouldn't think it would be a blocked core...also check the radiator cap...

Sounds like it is time for a cooling system and heater core reverse flush and fill.