1979 Silverado A/C fan weak - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Johnny Merder · 08-25-2012, 07:50 PM

Does anyone know how to increase the fan force or a replacement fan with more force? My A/C is plenty cold but doesn't see like it has much force? I would love to replace the fan motor or squirrel cage to increase flow?

Thanks

slam59 · 08-26-2012, 12:16 AM

There were some old threads that were saying if you clean out where it blows from, it makes a night and day difference. My wifes 77 3/4 ton is the same way, cold, but not very much force blowing out. Fan sounds like it is blowing pretty hard, but it does not blow hard. Even when on high setting for fan blower. So i am thinking mine is clogged up. Yours sound the same? They say you will be surprised what you find that gets sucked up in there.

**hatzie** · 08-26-2012, 01:45 AM

I pulled 9mm, 30-06, & .22 shells, several keys, Bic pens, and several inches of packed dog hair, dirt, and leaves out of my heater box on the 76.
Between the mud, hair, and mold the evaporator looked like a disgusting parody of a chinchilla.

20 minutes with a brush, wet vac, Simple Green, and insane amounts of water from my garden hose made it much better.

gchemist · 08-26-2012, 07:44 AM

Clean out the housing first. Second, buy a new blower motor. I just replaced mine. $16 for a new one. I took the air drum off the old one to install on the new one. Wow, talk about blowing some air in the cabin. I can hear the air running through the air ducts. The old motor was hard to start up. It took so many amps that it was blowing fuses. The bearings were worn out. Spining by hand, I could feel the drag. Best $16 I've spent on my A/C.

Johnny Merder · 08-26-2012, 06:11 PM

I recently got my truck all put back together, everything in HVAC system has been replaced, there was alot of junk in the housing when i did have it appart.
Does anyone have any other ideas?

Thanks

gchemist · 08-26-2012, 08:11 PM

Make sure the fan has a good ground.

Johnny Merder · 08-27-2012, 11:15 AM

I will check ground and see if that does anything. It does sound like the fan is running at ful capacity, I was also reminded I need to maks sure all the mode doors are working correctly inside the HVAC housing.

08-25-2012, 07:50 PM	#1
Johnny Merder Registered User Join Date: Jun 2011 Location: Jasper, In Posts: 109	1979 Silverado A/C fan weak Does anyone know how to increase the fan force or a replacement fan with more force? My A/C is plenty cold but doesn't see like it has much force? I would love to replace the fan motor or squirrel cage to increase flow? Thanks

08-26-2012, 12:16 AM	#2
slam59 Registered User Join Date: Nov 2011 Location: So. Calif Posts: 305	Re: 1979 Silverado A/C fan weak There were some old threads that were saying if you clean out where it blows from, it makes a night and day difference. My wifes 77 3/4 ton is the same way, cold, but not very much force blowing out. Fan sounds like it is blowing pretty hard, but it does not blow hard. Even when on high setting for fan blower. So i am thinking mine is clogged up. Yours sound the same? They say you will be surprised what you find that gets sucked up in there. __________________ 1974 C10 swb 350 1977 3/4 ton Silverado 454 1999 2 door 2wd Tahoe

08-26-2012, 01:45 AM	#3
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,932	Re: 1979 Silverado A/C fan weak I pulled 9mm, 30-06, & .22 shells, several keys, Bic pens, and several inches of packed dog hair, dirt, and leaves out of my heater box on the 76. Between the mud, hair, and mold the evaporator looked like a disgusting parody of a chinchilla. 20 minutes with a brush, wet vac, Simple Green, and insane amounts of water from my garden hose made it much better. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful.

08-26-2012, 07:44 AM	#4
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: 1979 Silverado A/C fan weak Clean out the housing first. Second, buy a new blower motor. I just replaced mine. $16 for a new one. I took the air drum off the old one to install on the new one. Wow, talk about blowing some air in the cabin. I can hear the air running through the air ducts. The old motor was hard to start up. It took so many amps that it was blowing fuses. The bearings were worn out. Spining by hand, I could feel the drag. Best $16 I've spent on my A/C. __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

08-26-2012, 06:11 PM	#5
Johnny Merder Registered User Join Date: Jun 2011 Location: Jasper, In Posts: 109	Re: 1979 Silverado A/C fan weak I recently got my truck all put back together, everything in HVAC system has been replaced, there was alot of junk in the housing when i did have it appart. Does anyone have any other ideas? Thanks

08-26-2012, 08:11 PM	#6
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: 1979 Silverado A/C fan weak Make sure the fan has a good ground. __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

08-27-2012, 11:15 AM	#7
Johnny Merder Registered User Join Date: Jun 2011 Location: Jasper, In Posts: 109	Re: 1979 Silverado A/C fan weak I will check ground and see if that does anything. It does sound like the fan is running at ful capacity, I was also reminded I need to maks sure all the mode doors are working correctly inside the HVAC housing.



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