Author Topic: Started Heater Core Replacement...??  (Read 7754 times)

Offline ehjorten

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Started Heater Core Replacement...??
« on: October 24, 2013, 10:14:19 AM »
So...9 days until opening day of Elk hunting.  Yesterday I started the work to replace my leaking heater core.

My question...what is the proper replacement battery tray?  Mine is a 1991 V3500.  I find that there isn't very good documentation for the 88-91 crew cabs in terms of what is the proper part.  I just wanted to check to see that I am ordering the correct one.  I know not a lot changed on these from the '87 year, but there are differences.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline pholliday1

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Re: Started Heater Core Replacement...??
« Reply #1 on: October 24, 2013, 10:25:14 AM »
Hello friend!

The differences in the battery tray are very subtle, I actually had one from an 85 1 ton sitting next to my 90 crew cab just last night. The only difference I could see is on the tbi models there is a small tab that sticks up on the outside edge where the hold down bolt goes. The tab has a hole in it for a plastic keeper (one way push in plastic type) to keep the alternator wire and main power wire together. Its really just more of a organization neatness thing more than any thing else. Most trucks that plastic keeper is just a distant memory. And like most other things the GM trays seem beefier than the repops. I already changed my core LOL good luck............
VETERAN AND LIFETIME NRA MEMBER. WHAT DO YOU STAND FOR?
1991 V3500 CREWCAB SRW 454TBI GMC
1991 v3500 crewcab SRW 454tbi 480le 6" lift
1990 V3500 crewcab Dana 60 FF 14b 5:38 ratio 40 inch 11" lift
1989 v3500 crewcab 454TBI 5" lift

Offline ehjorten

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Re: Started Heater Core Replacement...??
« Reply #2 on: October 24, 2013, 10:46:40 AM »
Oh I've changed my core in the '77 K20 and completely rebuilt the heater box.  Made a world of differnce with regards to air-flow magnitude and air-flow control!  Elk hunting snuck up on me and I have been putting it off because of the shop work.  I wanted to leave myself enough time to deal with any issues during the disassembly.  Shop work has been going slow, but I am getting the deck on the roof, then inspection and then underlayment and architectural comp.  Really slow going unfortunately as a one man construction crew.  The last of the big, laborious shop tasks.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline ehjorten

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Re: Started Heater Core Replacement...??
« Reply #3 on: October 24, 2013, 11:04:04 AM »
Anyone have experience with the replacement front wheelwells and battery tray on this site?  How is the quality?  Battery tray I am figuring is pretty routine.  As pholliday1 has said...thinner metal.  Replacement wheelwells?  As good as factory?  Same gauge?  Same fitup?
« Last Edit: October 24, 2013, 11:06:31 AM by ehjorten »
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline pholliday1

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Re: Started Heater Core Replacement...??
« Reply #4 on: October 24, 2013, 01:48:03 PM »
almost forgot, I changed my blower motor to a early 90's? fan motor from a c/k  after reading it in a thread here sorry cant remember thread or year of motor, but the motor really worked better than the old one. I used Keystone inner wells before and no where as thick as OEM. No experience with other brands. Are yours rotted?
VETERAN AND LIFETIME NRA MEMBER. WHAT DO YOU STAND FOR?
1991 V3500 CREWCAB SRW 454TBI GMC
1991 v3500 crewcab SRW 454tbi 480le 6" lift
1990 V3500 crewcab Dana 60 FF 14b 5:38 ratio 40 inch 11" lift
1989 v3500 crewcab 454TBI 5" lift

Offline ehjorten

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Re: Started Heater Core Replacement...??
« Reply #5 on: October 25, 2013, 10:07:33 AM »
I think I told you about that blower motor!  Yeah...'94 C/K blower motor.  Only works for those with the 4-Seasons A/C.  I've got one in the '77 and one in the '91.

Last night I got the heater box out.  It is actually quite different in design than the older ones.  It is all plastic.  Both halves of the box are plastic.  The mode door is plastic and all of the vacuum pods are plastic.  Also their is a third door that opens and closes the ducts to the dash.  The linkage between them is a little more complex.  It took me a little head scratching to get it all separated.

Got the back half all cleaned-up and installed the new heater core.  I was a little dissappointed that the new heater core was aluminum and not brass.  I know the aluminum is lighter and they can make the heat transfer more efficient because the aluminum is easier to draw-out, but I just feel like it isn't going to last another 20 years.  I also removed the staples from the defrost door and cleaned it up so now I am ready to put new foam on the door.

Cleanup the main case body and put it back together!

My wheelwells are in pretty good shape, but a little corrosion here and a few cracks there, etc.  Makes me want to just get nice new ones...or...good used ones that I can clean up and repaint and then swap-out later.  I need to get a '91 radiator core support too.  Mine has a few issues.
« Last Edit: October 25, 2013, 02:36:36 PM by ehjorten »
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline pholliday1

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Re: Started Heater Core Replacement...??
« Reply #6 on: October 25, 2013, 10:31:54 AM »
What's a heater core support? maybe I call it something different....... Opening day of whitetail season in the AM no Elk here :( :( :(
Going in deep in the Adirondack mountains Gonna give them 5:38's, Detroit lockers and my 40's a workout. Hopefully they do the job and I don't have to break out the winch.
VETERAN AND LIFETIME NRA MEMBER. WHAT DO YOU STAND FOR?
1991 V3500 CREWCAB SRW 454TBI GMC
1991 v3500 crewcab SRW 454tbi 480le 6" lift
1990 V3500 crewcab Dana 60 FF 14b 5:38 ratio 40 inch 11" lift
1989 v3500 crewcab 454TBI 5" lift

Offline ehjorten

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Re: Started Heater Core Replacement...??
« Reply #7 on: October 25, 2013, 02:37:19 PM »
You must be mistaken...I said Radiator Core Support!  ;D
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline Captkaos

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Re: Started Heater Core Replacement...??
« Reply #8 on: October 25, 2013, 04:07:48 PM »
I have experience with the parts, they all fit the same.  The inners were already thin from the factory, these are comparable.  I sell a lot of battery trays.  What I sell is going to be no different than many of the large suppliers.  We all get parts from the same place.


Core supports for the 89-91 changed from the 81-88's... subtle differences though.

Offline pholliday1

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Re: Started Heater Core Replacement...??
« Reply #9 on: October 28, 2013, 12:34:43 PM »
Yup........ I was confused..........
VETERAN AND LIFETIME NRA MEMBER. WHAT DO YOU STAND FOR?
1991 V3500 CREWCAB SRW 454TBI GMC
1991 v3500 crewcab SRW 454tbi 480le 6" lift
1990 V3500 crewcab Dana 60 FF 14b 5:38 ratio 40 inch 11" lift
1989 v3500 crewcab 454TBI 5" lift

Offline ehjorten

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Re: Started Heater Core Replacement...??
« Reply #10 on: October 31, 2013, 01:39:35 PM »
Got it all put back together yesterday afternoon!  Just in time to leave for hunting tonight or early tomorrow.  Changing out the tube/hose assembly to the back of the intake manifold was a pain!  They didn't leave much room to get a wrench on the 1-1/16" Nut!  Luckily it came loose pretty easy!  The new foam on the defrost door made a good improvement to the defrost mode.  No leaks and no more fogging the inside of the windshield!

Plenty of heat again for those cold rainy Elk hunting days!

I was gonna do a step-by-step rebuild write-up this time, but as usual...I got to working fast and furious and didn't take enough pictures to show the whole process.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline Captkaos

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Re: Started Heater Core Replacement...??
« Reply #11 on: October 31, 2013, 08:50:42 PM »
I was gonna do a step-by-step rebuild write-up this time, but as usual...I got to working fast and furious and didn't take enough pictures to show the whole process.

Slacker... :)  hope you get a nice Elk!
« Last Edit: October 31, 2013, 08:52:41 PM by Captkaos »