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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: monster77k10 on February 21, 2013, 01:49:58 pm

Title: heater core on my 77
Post by: monster77k10 on February 21, 2013, 01:49:58 pm

Im pretty sure I need to replace the heater core on my 77 k10. There's smoke coming from the dash and drips antifreeze on occasion. I was wondering if anyone might have a link of the schematic to take the dash and other misc. Parts to get to the heat or core.

Title: Re: heater core on my 77
Post by: bake74 on February 21, 2013, 02:43:22 pm

    My shop manual only covers 74 - 76 trucks otherwise I would scan in the pages you need.  Capt. is trying to get all the manuals for our trucks scanned in, until then someone else will have to provide them for you. 
    I am sure someone will pipe here and help out.

Title: Re: heater core on my 77
Post by: monster77k10 on February 22, 2013, 08:29:08 pm

So I did a little research and found out I can bypass the heater core by unrouting it from the coolant system to buy me some time. Anybody know how I can do this? Just plug the hose? Or is there a way to bypass it completely?

Title: Re: heater core on my 77
Post by: 79gmc15 on February 23, 2013, 12:42:44 am

Some people put a ball valve in the inlet hose. Or you can hook the inlet hose to the outlet hose into a "loop". I think the il / ol hoses are different sizes, so you will need some kind of reducing coupling.

Title: Re: heater core on my 77
Post by: monster77k10 on February 23, 2013, 02:32:52 pm

I took the hose that went from the radiator to the fire wall off and attached it straight to the one coming off of the intake manifold. I noticed it wanted to over heat at first now its somewhat steady at running temp sometimes fluctuating a bit higher.