Is this Factory ???

[CYLFD]

Is this a Factory fuel cut off ? If so might just leave it what do you think?

[rsavage]

That is the valve for auxiliary gas tanks.

[RHGuyettejr]

Yep thats for the bedside gas tanks..... heres a pic.





You can see those nasty grey colored fuel doors on the side, the tanks are behind the fleetsides in front, if you look close you can just barely see the underside hanging below the bed.

[Lee H]

Not factory but dealer installed.
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[Sideways]

Originally Posted by CYLFD

Is this a Factory fuel cut off ? If so might just leave it what do you think?

I would say yes it is factory and the N40 option exactly like mine.

[CYLFD]

Cool deal thanks now I wonder if I should 86 it or find a cool use for it
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[jocko]

I always thought the L21 was the single driver's side (factory) installation while the dual aux tanks were dealer add-ons (with no SPID callout)(?)

Sideways, do you have dual aux tanks or single? I believe the code would be left of the nomenclature (out of the above SPID pic to the left) and that N40 is pwr steering, but not positive on that. Holy cow I love that truck...

[jocko]

Originally Posted by CYLFD

Cool deal thanks now I wonder if I should 86 it or find a cool use for it
Posted via Mobile Device

Absolutely keep it!! Can't get too far on a single cab tank in these things

[leddzepp]

Originally Posted by jocko

I always thought the L21 was the single driver's side (factory) installation while the dual aux tanks were dealer add-ons (with no SPID callout)(?)

Correct. The dual tanks were dealer add-ons. The single aux. tank was available as a factory option in 72, and the switch used to change tanks was on the dash for those units.

[leddzepp]

Here is a pic of the 72 aux fuel tank switch. It is on the left side of the dash, just above the A/C vent.

[72 K20]

Here is a pic of the 72 aux fuel tank switch. It is on the left side of the dash, just above the A/C vent.

Is that an electric unit ? Vacuum ? I've never seen one of these,,, have had two with the dealer tanks in the bedside and have a parts truck with a right side poly tank that fills through the wheel well.

Learn something new each day !!!!

[Sideways]

Originally Posted by jocko

I always thought the L21 was the single driver's side (factory) installation while the dual aux tanks were dealer add-ons (with no SPID callout)(?)

Sideways, do you have dual aux tanks or single? I believe the code would be left of the nomenclature (out of the above SPID pic to the left) and that N40 is pwr steering, but not positive on that. Holy cow I love that truck...

Sorry ,wrong side of the spid.Mine says NL2 and I have a switch on the dash, but that only switches the gauge to tell how much is in each tank.The manual switch on the floor actually controls the flow from each tank.Oh yeah,single aux tank and the switch on the dash matches the headlight and wiper switch.

[Bill72]

The single factory Aux fuel tank is RPO NL2. The lever on the floor is to switch tanks. The knob on the dash is to switch the gauge over to read the aux tank fuel level.


Sideways beat me to it.

[Sideways]

Originally Posted by Bill72

The single factory Aux fuel tank is RPO NL2. The lever on the floor is to switch tanks. The knob on the dash is to switch the gauge over to read the aux tank fuel level.


Sideways beat me to it.

I could'nt have said it better myself.

[Sideways]

Originally Posted by RHGuyettejr

Yep thats for the bedside gas tanks..... heres a pic.





You can see those nasty grey colored fuel doors on the side, the tanks are behind the fleetsides in front, if you look close you can just barely see the underside hanging below the bed.

If anyone has the plastic indicator bezel to sell let me know mine is history.
Thanks!

[leddzepp]

Originally Posted by Bill72

The single factory Aux fuel tank is RPO NL2. The lever on the floor is to switch tanks. The knob on the dash is to switch the gauge over to read the aux tank fuel level.


Sideways beat me to it.

Oops...I thought that it also controlled the tanks

[jocko]

Ha, sorry - I misread the SPID - NL2 looks right, I was looking at NL2 embedded in a string of #'s and choppped off the wrong ones...

So, I'm still a little confused - I've seen many trucks that have the floor valve for DUAL aux tanks. But I've never seen one with DUAL tanks and with both switches (floor and dash). I think I was in the same boat as Scott with how I understood it.

So, Sideways - is your floor switch a 2-position switch since you only have the single aux tank?

Has anyone seen a dual aux tank truck with the 3-way floor switch AND the dash switch? I haven't seen that, nor have I ever seen dual aux on a SPID.

So (i'm saying "so" a lot...) NL2 = single driver side aux tank
and NL2 included a floor switch for flow and a dash switch for gauge reading.

How did a dual aux tank truck switch what the fuel gauge showed (since i've never seen a dual aux tank truck with a dash switch...)? Or COULD it display the other tank quantities?

[SS Tim]

Factory aux tanks. Saddle tank(s) were offered as dealer installed plus there were a lot of aftermarket companies and installation variations. Knew of one truck that had four tanks (cab,saddles and rear aftermarket) with 95+ gal capacity.

[special-K]

I have a '71 Custom Camper brochure that lists the auxiliary tank as an available option. I believe it's a brochure for '72s "printed" in 1971. It threw me for a loop at first.

The aftermarket (not only installed by dealers) tanks would have a three position toggle switch to control the gauge mounted where ever whoever installed it thought was best. My '72 GMC has one with an aluminum plaque with Left/Main/Right labled.

[SS Tim]

You must mean this one.

[ryanroo]

Tim, do you have pics of the inside of the bed on those options perchance? i am going to try to copycat the NL2 style in the N18 location for my relocated home made rear tank. i have a plan for the the inside of the bed, but i want to see if my plan is like the OEM stuff

Thanks
Ryan

[70c10-08]

Originally Posted by SS Tim

Factory aux tanks. Saddle tank(s) were offered as dealer installed plus there were a lot of aftermarket companies and installation variations. Knew of one truck that had four tanks (cab,saddles and rear aftermarket) with 95+ gal capacity.

95+ gallons of fuel on a 67-72 C/10-30? wouldn't that hurt you more than help ya? all that weight your mpgs would really suck

[Sideways]

Originally Posted by jocko

Ha, sorry - I misread the SPID - NL2 looks right, I was looking at NL2 embedded in a string of #'s and choppped off the wrong ones...

So, I'm still a little confused - I've seen many trucks that have the floor valve for DUAL aux tanks. But I've never seen one with DUAL tanks and with both switches (floor and dash). I think I was in the same boat as Scott with how I understood it.

So, Sideways - is your floor switch a 2-position switch since you only have the single aux tank?

Has anyone seen a dual aux tank truck with the 3-way floor switch AND the dash switch? I haven't seen that, nor have I ever seen dual aux on a SPID.

So (i'm saying "so" a lot...) NL2 = single driver side aux tank
and NL2 included a floor switch for flow and a dash switch for gauge reading.

How did a dual aux tank truck switch what the fuel gauge showed (since i've never seen a dual aux tank truck with a dash switch...)? Or COULD it display the other tank quantities?

Without checking,I believe mine has three positions and I used the third position and it acted like a theft prevention as it shut the fuel off. The dash switch only showed what is in each tank so you can check whether the second tank is full or empty at any time."So" you must make sure you have it in the correct positon for the tank you are currently using.

[special-K]

Originally Posted by ryanroo

Tim, do you have pics of the inside of the bed on those options perchance? i am going to try to copycat the NL2 style in the N18 location for my relocated home made rear tank. i have a plan for the the inside of the bed, but i want to see if my plan is like the OEM stuff

Thanks
Ryan

Here's the '69 aux. tank fill cover:

[Sideways]

Would that be the same one the blazer uses?