heat not working?

[02bigstrokin]

ive been fighting this problem for a few weeks now. the air coming out of the vents is luke warm at best. its completly full of coolant, ive tryed 2 different stupid digital dash controllers, reset them over and over and im not getting anywhere. the thermostats were new gm parts about 1 year ago. upper radiator hose is hot and lower one is ice cold? i need to figure this out as the new owner will be picking it up monday. thanks in advance

 

[Noreaster]

you sure your getting circulation? impeller might have come loose in the pump

 

[DIESELMAFIAPER.LB7]

^ kinda what i was thinking

 

[02bigstrokin]

The shaft would have to break on mine in order to quit working cause it has a key in it and it has a stainless cap on the end with a bolt locktited in it. Plus that has happened to me before and the truck would overheat real quick. Temp never goes above 200 now. I think it's something to do with te stupid blend doors. Man I wish I had the oldschool one with a cable and not this dumb electronic crap

 

[THEFERMANATOR]

What is the temp of teh 2 heater hoses? Is one hot and the other cool? I've had to flush out a couple of heater cores here lately for no heat and overheating in gassers.

 

[02bigstrokin]

What is the temp of teh 2 heater hoses? Is one hot and the other cool? I've had to flush out a couple of heater cores here lately for no heat and overheating in gassers.

yeah the one that comes out of the top of the thermostat housing is hot going in the heater core. the other is cool.

 

[blk smoke lb7]

Sounds like a plugged heater core for sure IMO Good luck

 

[02bigstrokin]

Sounds like a plugged heater core for sure IMO Good luck

How do u clean it?

 

[blk smoke lb7]

I used compressed air after taking both hoses off the last grand prix i did but if you motor compartment in detailed very niclely you probably want to put a long hose with a hose clamp on it and make sure the end is either hanging down past the bottom of the motor or in a bucket to catch the slop that comes out.

Also the colling system is used to 15 psi be very careful how much air you hit it with and you can damage the core and trust me you dont want to pull the dash out to change it.which ever hose is cold is the 1 you want to hit with the air that way if its blocked at the begining it will hopefully clear up easy and you dont have to force it all the way thru the core.

 

[THEFERMANATOR]

I like to use a garden hose and flush em that way. It is VERY easy to crack a heater core filled with coolant if you hit it with even 50 psi of pressure. Take the 2 heater lines off and reverse flush it with a garden hose, then gently use low air pressure to blow out the water and hook the heater lines back up.

 

[sweetdiesel]

I've had a fuse under the hood go out and caused it to blow cold air, it happened on my first lb7 a few times

 

[GMC_2002_Dmax]

The shaft would have to break on mine in order to quit working cause it has a key in it and it has a stainless cap on the end with a bolt locktited in it. Plus that has happened to me before and the truck would overheat real quick. Temp never goes above 200 now. I think it's something to do with te stupid blend doors. Man I wish I had the oldschool one with a cable and not this dumb electronic crap

My electricians Hummer was doing the same thing, he used my TECH2 to reset all the blend doors and all was well after that.

Find a TECH2 or someone with one.

Good Luck.

 

[blk smoke lb7]

I would think both hoses would be hot if it were blend doors or a bad fuse.Pretty sure something is blockeed in the heater core.

 

[02bigstrokin]

I took both hoses off and ran water though the core with a hose and hit it with compressed air and all is well now. Thanks for the help