92 k1500 blazer not heating up

[01XJ]

I bought a 92 full size blazer 5.7 and when i first got it it ran great and still does. When i first bought it had no heat at all, i checked the coolant and it was so dirty i couldn't tell if it was dex cool or the green crap that went rusty. My Guage always read just under.210. I did a full flush until the water coming out was crystal clear put a new tstat in and cap and filled it with the green stuff. I let it run for 30 min got the air out of the system but my guage was at like 60. All hoses were burning hot to touch but in still had no heat. I took it clear from orem.to af and back on the freeway and it never reached a 100deg. And still no heat. So i cut the hoses to the heater core and flushed the hell out of it and it was nasty. It had all kinds of crap. I did it one way then the other until the water was clean. Put it all back together toped it off and went for another ride. Temp guage still never over a 100 but a had some heat not much but it was warm only on low or med. High just blows cold. I have replaced every sensor on this car. Tps. Iac, coolant temp sensor the sensor that runs the guage you name it its been replaced. Full tune up fresh plugs wires, cap, rotor the whole works. I noticed thebwater pump leaking a little so i did it also. Why would my guage work before with dirty crap why do i still have no heat I'm at a loss. I know the guage works i grounded it out and it will go all the way to hot then bsck to cold. Any suggestions? Is it bad it only runs at 100 maybe 105 on a warm day. I can drive it miles and get out and open the radiator cap with no issues its cold to the touch. It's not leaking or losing fluid my tank and radiator are full. It runs like a raped ape i just can't fugue out this cooling system since i did a flush. Even the hose under the dash going in to the core is hot but i just can't get heat. Everything has been replaced, any help ideas would be great. Thanks in advasnce , jeff

 

[bryson]

It sounds to me like there is still air in the system, which would explain why your gauge is reading incorrectly, and why there isn't heat.

Maybe the flush stirred up enough crap to cause a plug somewhere in the system? You certain the t-stat didn't get installed backwards? Can you see the heater valve moving when you switch the selector from cold to hot? Is there a chance you got a reverse flow water pump? IIRC, V-belt and serpentine water pumps turn opposite directions.

Is there a fitting or hose on top of the engine that you can open up to bleed air from the system? Maybe pull a heater hose and fill with coolant from there?

Good luck!

 

[sawtooth4x4]

Try taking your heater hoses off the engine. Then run some water through the heater core in reverse of normal flow. It should flush out any of the crap in the heater core and the lines.

 

[boogie_4wheel]

On my '97, I let it idle with the radiator cap off. It would come up to temperature, and would show so on the gauge. As soon as the t-stat opened the radiator level would drop about a gallon, if not more. I would refill to the neck again and install the cap. Then would have the overflow filled a little bit above the cold mark. As it cooled it would draw a little fluid from the overflow, and I would never have to touch it again.

For your issue, I would pull and verify the t-stat. Capture what clean coolant you can, then do a 2nd flush with the garden hose.

 

[01XJ]

Thanks for the tips guys. I never really thought of the tstat being in wrong. Im pretty sure it's in right but it's such a easy thing to check i will do that tom and update if it was in right.... knowing me even though i checked i probably put it in wrong still