Heater Not Working Well

[Colorado Yeti]

The heater core blew in my 65k '99 2-door Tahoe so I replaced it, along with a new radiator, all new hoses and a new new thermostat. The heater core job was actually quite easy compared to many other vehicles that I have done in the past. When I filled up the system with coolant, I made sure to purge all of the air out of the core. The problem now is that the heater does't really make much heat, kind of lukewarm only. The thermostat is working properly, and the temp gauge is between 190 - 200 degrees while operating. This doesn't really bother me as I am extremely warm-blooded but it is not so nice for my passengers, especially the ones in the backseat. Anybody else have this problem after replacing a heater core? Any suggestions?

 

[OR VietVet]

I know you said the temp gauge reads 190 to 200 but I still want to know the thermostat temp you put in. If the gauge is accurate then, IMO, the temp is too low. Normal, again IMO, would be closer to 210. Try using a piece of cardboard and put in front of the radiator and see if temp climbs and more heat is coming out. Make double sure that there is no air in the system. Also, was the old radiator a 2 row and you decided to step up and install a 4 row?

Another also, did you install a new radiator cap? If the cap is not holding the correct pressure it can bleed off pressure and temp.

 

[exp500]

Look at the vacumn line at the coolant shutoff valve. Hope this helps

 

[OR VietVet]

Since you already replaced combination switch, check all the connections at the steering column also. East 302 posted great info for reverse light problem. Check your 3rd brake light to see if it is an led, if it is you may want to change it.There are a couple threads on that. Hope this helps

I do believe you meant to post at this in another thread.

 

[east302]

X2 on bleeding it again. With engine cool and cap off, start the engine and let it get to temperature. Top off the coolant as it drops when the thermostat opens. Repeat until no bubbles come up.

Are the hoses at the water valve routed correctly? Are they too hot to hold for more than a few seconds?

Does the water valve open and close? Push up and down on the metal rod at the bottom to cycle the valve. It should return to the down position if the a/c panel temp dial is not set to the “max” cold detent.

Top hose is from the intake, bottom one from pump.