heater problems
 

ok when i bought my truck it never heated up.i figured it was a thermostat.i changed that and the radiator cap.it gets a little warm but that it.also it starts drippiling out of the radiator overflow,when its running and after i shut it off.any ideas

as far as the little or no heat is concerned a couple of things could be that the valve controling flow thru the heater core is not opening up or the phlenum that holds the heater core is filled with debris loke 30years of pine needles or leaves
as far as the water flowing out the overflow don't fill the radiator when it's cold only fill when the motor is up to operating temp

The radiator problem is something a lot of younger guys don't know about.When the engine and radiator heat up the water/coolant expands overfilling the radiator in effect and causing it to run out the overflow.
The later cars used an overflow tank that let the coolant escape to the tank and then it was returned when the engine cooled and created a vacumm.All engines of the non-return line type will use some coolant.They should be filled on ocassion.
You can retro fit a coolant overflow and return easily, if you use the tank from a truck with one or install an aftermarket one.
New cars are required to have them for EPA, as are race cars to prevent wet spots on the track that cause slick spots.

Yes, like cdowns said, the valve controlling heat flow could not be working (assuming this is a non AC truck).

You can look at the flapper valve from inside the cab....it is where the heater control cable goes into the heater box, under the dash in the passenger side footwell. There is a little plastic piece that seals the rectangular hole where the control cable goes in, pop it out and have a look. Make sure the cable is still attached to the lever on the flapper valve, and that it is opening and closing all the way.

If that checks out, you proably have a heater core plugged with pine needles or something. You need to remove it....and proably replace it too. A new core is only around $25, and as long as it is out it would be a good idea to replace it.

Yellow72 is right. I just had to replace mine. A/C version. Got it at Autozone. It was about $25.

:flag: :gmc: :bowtie:

Same here I just replaced the core in the blazer and it seem's to blow really hot. I also replaced the fan switch that control's the fan speed .. I never knew there was 3 speed's for the fan..

lol! of course they are 3 speeds! mine is:
1). off
2). on but nothing comes out the vents
3). on and air is blowing like a hurricane
:D