Cold Climate Package - special heater

[wazzabie]

What makes the heater and defroster special in the cold climate package? Is a larger fan used?

K81 - Cold Climate Package (Including Special Insulation, 66 Amp Alternator, Special Heater & Defroster, Engine Block Heater, HD Battery.)

[blazer2007]

bigger heater core I think

[Palf70Step]

The only thing I have found for K81 is the larger alternator (66 AMP). It may vary a little depending on the year of the truck, but that was the only code description I have found.

[kipps]

If someone knows how to source the K81 heater core, I'd be happy to know about it, particularly if it can be retrofitted to a non-K81 truck.

[Pontiac1976]

I’m not sure if your unit was on a A/C unit or none A/C unit that it came from.?

I had a cold area heater box that had an extra flap that could be opened at feet heat.
( 1975 350 A/T TH350 none A/C unit) 37AMP/43AMP.

If it were a A/C unit it may have had a VAC access climate controls with one or two cables. Those would have the higher amp ALT. as the 66AMP.( might have had a amped up blower)

Or just manual cable only unit with A/C not to common after 80.
Not sure if this will help or not.

[wazzabie]

Originally Posted by Pontiac1976

I’m not sure if your unit was on a A/C unit or none A/C unit that it came from.?

I had a cold area heater box that had an extra flap that could be opened at feet heat.
( 1975 350 A/T TH350 none A/C unit) 37AMP/43AMP.

If it were a A/C unit it may have had a VAC access climate controls with one or two cables. Those would have the higher amp ALT. as the 66AMP.( might have had a amped up blower)

Or just manual cable only unit with A/C not to common after 80.
Not sure if this will help or not.

I have a cold climate package with no ac on a 78. The heater has always been great and quickly warms up inside. I didn't know about the extra flap at the floor.

How do you open the extra flap? I've always just used the controls in the dash.

[cadillac_al]

Pretty interesting. I live in a cold climate and this is the first I have heard of this option. I have never seen in on any of my SPID's either. My 76 GMC is from North Carolina and the heat is so hot it takes my breath away.

[Pontiac1976]

There is a cable that runs of one of the leavers. It's nice on the cold night in fall and winter to warm up the floor take some of the cool out of the floor area this is only on the None A/C units. My 84 did not have it the 75 and the 77 all three where made in Canada & None A/C units. You really feel the difference on a good highway drive when it cold.

[wazzabie]

Originally Posted by Pontiac1976

There is a cable that runs of one of the leavers. It's nice on the cold night in fall and winter to warm up the floor take some of the cool out of the floor area this is only on the None A/C units. My 84 did not have it the 75 and the 77 all three where made in Canada & None A/C units. You really feel the difference on a good highway drive when it cold.

Does the non cold climate controlled 73-79 trucks not have the floor heater?

I have no ac and the cold climate package. I do have a floor heater.

[legendman]

Some info here on it

http://www.chuckschevytruckpages.com...s_1973-87.html

K81 - Cold Climate Package (Including Special Insulation, 66 Amp Alternator, Special Heater & Defroster, Engine Block Heater, HD Battery.)

[legendman]

Also info here about it.
It is sideways on page 13

https://www.gmheritagecenter.com/doc...t-Suburban.pdf

[ETKTRYD]

My 78 was non A/C. When the heater motor went I replaced it with a motor for an A/C unit. You could cook pizza on the dash. It put out crazy heat.

[wazzabie]

Originally Posted by ETKTRYD

My 78 was non A/C. When the heater motor went I replaced it with a motor for an A/C unit. You could cook pizza on the dash. It put out crazy heat.

Not sure I follow. Before the old motor went bad was it better with more heat then the newer a/c motor?

[Shugalou]

^ Sounds like it put out more heat with the upgrade fan. Good tip as my truck never feels like it heats up enough.

[ETKTRYD]

Yes.…. Crazy heat with the new larger A/C motor.

[cadillac_al]

I only use my blower for a couple minutes then keep it on low the rest of the day with temp in the middle. Any higher than that and I literally can't breath.

[wazzabie]

Originally Posted by ETKTRYD

Yes.…. Crazy heat with the new larger A/C motor.

Interesting, the heat is great currently with the stock heater. You found a nice upgrade.

[doubleclucker]

Up here in Canada the heavy duty heater option wo/AC consisted of and extra position on blower switch low- med1- med2 -high. there was an extra wire to the resistor and and it was shaped similar to the a/c resistor with the extra circuit for almost no resistance so the blower motor blew faster than normal and it was a little bigger armature with the cooling tube added to it .
It was easy to retrofit because the blower wiring harness was separate but it still plugged in to the main harness at the blower switch (brown) and at the blower box you could drill the hole for the cooling hose and enlarge the hole for the resistor. Easy way to tell HD or not , is the extra position at blower switch or different shape resistor at box.
Parts-
Blower box (or modify)
Blower motor
Blower cooling tube
Cooling tube to box plastic adapter + screw
4 position resistor
4/wire wiring harness to switch
Extra position blower switch

[farmall]

Originally Posted by wazzabie

I have a cold climate package with no ac on a 78. The heater has always been great and quickly warms up inside. I didn't know about the extra flap at the floor.

How do you open the extra flap? I've always just used the controls in the dash.

I wish you would take some pics of the floor plenum and firewall blower motor area.

Is your switch a 4 position switch?

I have an 81-82 Diesel parts truck with a full firewall insulation in the engine compartment. It has no glove box door so no codes. Im guessing the insulation is to keep the clatter out but it should keep the heat in the cab as well, I would think.

The L&R sides of the windshield on my 81 K30 will freeze into a thick icy mess if I have the defroster on while it is snowing and going down the road. The only way to be able to drive is to keep the windshield cold. I am switching to an AC cab but I want to be able to fry bacon in there.

[wazzabie]

Originally Posted by farmall

I wish you would take some pics of the floor plenum and firewall blower motor area.

Is your switch a 4 position switch?

I have an 81-82 Diesel parts truck with a full firewall insulation in the engine compartment. It has no glove box door so no codes. Im guessing the insulation is to keep the clatter out but it should keep the heat in the cab as well, I would think.

The L&R sides of the windshield on my 81 K30 will freeze into a thick icy mess if I have the defroster on while it is snowing and going down the road. The only way to be able to drive is to keep the windshield cold. I am switching to an AC cab but I want to be able to fry bacon in there.

Yes - I have the 4 position fan switch and I know this is the switch that came with the cold climate package. Also I have insulation inside on the firewall.

Is the 4 position fan switch only on the cold climate packages?

[Hammered 77]

Following, any pictures?