Constant heat

[blg4351]

I have an 85 K5 that constantly blows heat through the floor vent with the blower motor and resistor disconnected. I know that they had that flow through ventilation crap. With 100 plus degree weather and no A/C at the moment its pretty miserable driving my beast around. I figured that it would stop with all of that disconnected but it doesnt. Any ideas on what will cause this and how can i get it to stop?

 

[gotblazers]

i got the same thing. Just push the fan selector all the way left. It gets pushed open pushing the lever right from air pressure

p.s this is for a 76 k5 so we might be in different boats but thats just my .02

 

[hillbilly deluxe]

My Sub was that way. It's going to circulate hot water through the heater core no matter what. I put a 1/4 turn valve in the pump side heater hose in the engine compartment to shut off the water going into the cab altogether. It seemed to help.

 

[folkenheath]

Yep, there is no vacuum shutoff valve on the coolant through the heater core. Also, with the cowl intake on the HVAC system, when you are moving there is air flowing whether the fan is on or not. Your best bet is to make sure it's set to the coldest setting so the air goes mostly around the heater core. But also, much of the sealing pieces (some foam) inside the heater box will let some air go by anyway since they are probably old and dry rotted. I made new seals for that from sealing strips at the hardware store. You could also do like got blazers and put a shutoff in your heater hose. If you swapped a big block make sure it has the intake/WP bypass hose as well if you do that.

Also, some of the models(maybe older?) did not have a fan off position. Only low/med/high. So if you don't have a fan off you might consider getting a different controller with a fan off position.

 

[blg4351]

Yeah I am thinking of the valve method to throw on it. I only have the SBC. I don't think the new control head would work though being that i had disconnected everything. I was thinking that there was some flow through air coming from the cowl. Any info on a good control valve would be appreciated,

 

[hillbilly deluxe]

Just don't buy the cheapest one. I used a 1/4 turn ball valve made of brass. I think it was $15, but that was a few years ago.

 

[USSkoval]

This may sound silly, but do you have the temp turned down? If it's adjusted properly, the temp slider set to full cold will block off airflow through the heater core. The air blowing out will be no warmer than outside air temp.

 

[blg4351]

Yeah I have it at full cold. If air does come down through the cowling and it is pretty dang hot here that is probably the issue i am having then. I am also going to try to get a manual heater control valve.

 

[K5er4Life]

Kind of funny bc I am going to do the same thing and put a 1/4 turn brass valve in there. My truck as well had factory a/c but I removed it years ago. I would make sure that everything inside the diverter box is sealed properly and working (foam strips in good condition and the cable that controls the diverter is in good repair, that should take care of the heat issue.