No heat from heater.

[SAATR]

Alright Ill check that next. One thing I noticed when I was flushing the coolant was that when I pulled the drain plug, only half of the radiator drained. To drain the passenger side, I had to pull the lower rad hose. Is this normal, or does it sound like some kind of blockage? If so, if there any good way to flush it out, or should i just get a new radiator?

That isn't remotely close to normal. Replace the rad and the heater core.

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[Bob L]

Before throwing parts at it you really need to find what is causing the problem. I would first drain the cooling system, then with the drain closed pour water in the filler with the lower hose off the other side it should readily drain out if not you may need a radiator. As far as the heater core remove the hoses and stick a garden hose in the outlet side should be the manifold and run water through it should flow freely both ways. If you have water running through the core and no leaks replacing it is a waste of money. To flush a core I usually run water through backwards first then back and forth till it runs clear. 160 degrees is low water temp too it should be 180 at least I would test with a thermometer if you don't trust the gauge reading. If you can hold your hand on the upper radiator hose when warmed up it isn't heating up enough.

 

[cookseyb]

My 96 Impala SS did the same thing, Chevrolet had a tech service bulletin out that said it will get full of crud and need replacing. That is a major ordeal so I took the hoses loose and blew the water and crud out as best as I could then filled it with Lime-away and let it set for a few hours and flushed it again, refilled and it works as it should. FWIW

 

[superdave]

So as not to start another thread...

I had to borrow my dad's 89 GMC Sierra for a few days (my daughter had a wreck and she's driving my nice truck and I'm in my dad's POS). I went to pick it up yesterday and he say's "Oh yeah, the heat doesn't work". Fantastic.

I flush the heater core and it's flowing fine. Since I'm getting no heat at all, I'm assuming the blend door isn't functioning for the temp change. Where is the actuator for the temp function? I have tried searching the forum and googling, but I'm not getting what I need. The best I can figure out is that it's high in the center of the HVAC box assembly and may be a PITA to get to.