Gas Cap

[custodian]

I've switched from the 6.2 to a 350. I've kept the gas tanks as they were for a diesel with new tanks.

Will a vented gas cap for gas fit the filler neck, which is still set up for diesel?

 

[AuroraGirl]

I think the filler is physically thicker. I would assume it wouldnt fit threads, then. Unless the opening is the same and the neck is just bigger, but i never pump diesel so i wouldnt know if the nozzle is bigger or not.

Looking at rock auto, a vented gas cap can be had for diesel, too. So I would get a gas cap that says diesel for fitment then just use gas. maybe get one that doesnt say diesel or isnt green, just to not confuse anyone.

 

[RecklessWOT]

I think the filler is physically thicker. I would assume it wouldnt fit threads, then. Unless the opening is the same and the neck is just bigger, but i never pump diesel so i wouldnt know if the nozzle is bigger or not.

Looking at rock auto, a vented gas cap can be had for diesel, too. So I would get a gas cap that says diesel for fitment then just use gas. maybe get one that doesnt say diesel or isnt green, just to not confuse anyone.

idk much about diesels, never owned one and I never gave a **** to pay attention to the company trucks I drove. I feel like they were similar sized? Not sure about threads and whatnot, but it might be the same as like the old leaded filler necks. Same size as modern ones but without all the little flappy doors and check valves and ****

I could be totally wrong though, who knows.

Filler caps are dirt cheap. Just pick one up and see if it fits, worst case scenario you're out all of $10 max. Better yet, take one off one of your other cars (assuming you own more than just a diesel) or borrow one off a friend/relative's car/truck and just see if it fits

 

[AuroraGirl]

I've switched from the 6.2 to a 350. I've kept the gas tanks as they were for a diesel with new tanks.

Will a vented gas cap for gas fit the filler neck, which is still set up for diesel?

do you have a vent line on your tanks and is it separate from a return line, and are you using a return from the pump? if you are using a return from the pump, where is your vent line going? Do you have evap canister?

 

[custodian]

I think the filler is physically thicker. I would assume it wouldnt fit threads, then. Unless the opening is the same and the neck is just bigger, but i never pump diesel so i wouldnt know if the nozzle is bigger or not.

Looking at rock auto, a vented gas cap can be had for diesel, too. So I would get a gas cap that says diesel for fitment then just use gas. maybe get one that doesnt say diesel or isnt green, just to not confuse anyone.

I might just buy one for gas and one for diesel and then compare. Have to make sure it doesn't say "diesel". Giving this truck to my youngest granddaughter.

 

[custodian]

idk much about diesels, never owned one and I never gave a **** to pay attention to the company trucks I drove. I feel like they were similar sized? Not sure about threads and whatnot, but it might be the same as like the old leaded filler necks. Same size as modern ones but without all the little flappy doors and check valves and ****

I could be totally wrong though, who knows.

Filler caps are dirt cheap. Just pick one up and see if it fits, worst case scenario you're out all of $10 max. Better yet, take one off one of your other cars (assuming you own more than just a diesel) or borrow one off a friend/relative's car/truck and just see if it fits

No "flappy" doors on my filler necks. I'll take the one off the 88 wagon and see if that fits.

 

[AuroraGirl]

i couldnt find any data on the thread thickness, but the "shaft" appears the same and the threads look the same. i think you may be safe just buying a vented cap of your choice. did you read the part about venting and evap etc

 

[custodian]

I checked today, and the gas cap on the 88 Caprice wagon fit the tank filler tube on the truck. Will most likely buy a couple of vented caps.

 

[Craig 85]

@AuroraGirl here's some info on the fuel nozzle openings. My truck originally ran on Regular gas and had no cats (HD Emissions). I have the 15/16" openings with no flap.


Leaded Gasoline Nozzle: outside diameter of 15/16" (23.8125mm)

Unleaded Gasoline Nozzle: outside diameter of 13/16" (20.6375mm)

Auto Diesel Nozzle: same as leaded gasoline

Truck Hi-Flow Diesel Nozzle: 1 3/16" (30.1625mm)