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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: Stewart G Griffin on September 29, 2016, 08:11:48 pm
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i know----besides carrying a roll of paper towels are there other quick tips to help out the defroster? It's just not cutting it.
i know by 80 or so GM cars had very good defrosting systems because i remember going shopping for new cars with my parents to the pontiac and olds dealers and i was very impressed at the speed and efficiency of the defrosters.
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working a/c? modern cars the a/c kicks on whenever you have on the defrosters (at least gm)
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working a/c? modern cars the a/c kicks on whenever you have on the defrosters (at least gm)
Ah, that must be it. i took mine out. i'll just stick with the towels for now.......
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Are you sure your heater box is up to snuff? I have rebuilt 3 of these now and this is what I can tell you from my experience. The main problem with defrost in these trucks is the foam on the end of the defrost door! It gets old and brittle and falls away!
I have used pliers and bent open the staples that hold the foam on, removed the remnants of the old foam, used some wide foam like that used to seal canopies to the bedsides (about 1-1/4" wide, 3/16" thick with a PSA backing...going off of memory here, but just that roll of pickup and camper tape that is wide enough to cover the defrost door) and put the staples back in and bent them back over.
Make sure your blend and mode doors are functioning properly, put new foam tape around the perimeter of the heater core opening and couple all of that with a new blower motor...maybe even a new heater core while you have the thing apart and you will be amazed how well it works!
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Are you sure your heater box is up to snuff? I have rebuilt 3 of these now and this is what I can tell you from my experience. The main problem with defrost in these trucks is the foam on the end of the defrost door! It gets old and brittle and falls away!
I have used pliers and bent open the staples that hold the foam on, removed the remnants of the old foam, used some wide foam like that used to seal canopies to the bedsides (about 1-1/4" wide, 3/16" thick with a PSA backing...going off of memory here, but just that roll of pickup and camper tape that is wide enough to cover the defrost door) and put the staples back in and bent them back over.
Make sure your blend and mode doors are functioning properly, put new foam tape around the perimeter of the heater core opening and couple all of that with a new blower motor...maybe even a new heater core while you have the thing apart and you will be amazed how well it works!
Will look into it. Thank you.
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You also want to make sure all of your vacuum pots are working properly and don't have a ruptured diaphragm. I just push actuator on the diaphragm and then cover the vacuum port with my finger. It should hold in that position if the diaphragm is still good. Alternatively if you have one of those Silverline vacuum pumps you can use that to see that the diaphragms moves and holds a vacuum. Lastly...check all of your vacuum hoses to make sure they are in good repair.