Gasoline compatiblity of generic radiator / heater hose material ?

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Nov 11, 2020
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112
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Ontario, Canada
I'm doing some r&r work on a fuel filler neck that is mostly steel until the last 6 inches where it connects to my (plastic) fuel tank. This last part is about 1 or 1.5" diameter (about the same size as a rad hose) but the steel line for most of the neck is about an inch diameter. There is a smaller I guess vent line that runs along side this main filler line. Both of these lines are super crusty rusted, the vent line is actually gone in a few places (yes I have engine code for this). So I'm going to be cutting back the rusted parts and replacing with generic rubber line.

My primary question here is - is there _really_ any difference when it comes to gasoline compatibility with these hoses that are sold by the foot at your local parts counter? If you ask for heater hose or rad hose or fuel-line hose, are you getting a different compound for these things or are they they the same material, maybe some have internal reinforcement / mesh for high pressure? What I need here is obviously low / no pressure but don't want the gas to melt it in a few weeks / months etc.

Comments?
 
They must be different. I tried to use "heater hose" to re-route the evap vent in my XTerra (comes out on the frame rail and plugs with dirt if you off-road) and it had developed "dry rot"-type cracking when I happened to look at it again during another repair. I can't think of any other reason for that except for an incompatibility with fuel vapors.
 
Thing is, the short piece from the tank to filler neck is 1.25 inch diameter and your typical retail auto parts place likely won't have that size. They barely have 3/8 inch fuel-compatible line.
 
Unfortunately, you'll have to buy a 3-foot length - mail order.



These guys sell by the inch:

 
$25 a foot is insane. I'd want probably 2 feet because a lot of the steel pipe of the filler tube is rusted to hell so I'd cut it back quite a bit. Krazy price.

There's a place on-line (filler neck supply co.) - they're showing all 1.25" hose as out of stock. They're showing a Gates 3-ft section for $36 but again, out of stock. They have 1" hose, but the 1.25 to 1 inch reducer - yup - out of stock. ***?
 
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I found a local parts store (CarQuest) that said they had 3 ft x 1.25" ID fuel filler hose (Gates 76125) for $46 (USD all taxes in) so I bought it but now I see it's actually radiator hose. This hose is reinforced and looks like it can handle 100 or 200 psi, way beyond the zero psi required for a fuel filler line.

I was thinking of bringing it back, but I look at what my options are (both on line and locally) for actual fuel-compatible line and it's easily going to be double this price. This particular Dayco rad hose was made in Pakistan.

I know there's been a number of industrial / chemical plant fires lately and over the past few years, I wonder if the production of these rubber / nitrile products has been impacted.

So screw this, I'm going to use it. I've cut away the last foot of the rusted filler neck line so I'll use a wire disk to clean up the rest of the filler tube and then connect this hose to the tank and run it up on the outside of what's left of the filler tube as high as it will go, cut off any excess and clamp it at the top (the filler tube is 1" OD so I'll have to use a spacer made of something at the top).

The amount of persistant contact this hose is going to have with gasoline is going to be minimal, and the last foot will see the most transient exposure to gasoline anyways. I'll cut a small piece and throw it in my gasoline jerry can and see how it lasts as a test.

I notice that something called fuel-cell vent lines are also sold, a clear soft-plastic type of tubing, maybe 1/8" wall thickness, in large sizes like 1" and higher. What's that for? Is that type of line compatibible with gasoline?
 
Just go to the nearest "U-Pull-It" yard, and grab some fuel line off the latest and newest vehicle they have on the lot. Cheap and effective. Use the filler hose from the gas cap to the tank for the other parts. Lot's of cars in junk yards to get these parts cheap and they will work just fine.
 
I need at least a 2 ft length of this filler line since I've cut away some of the existing filler pipe due to rust. I doubt I'll find something that long in junked cars. And nothing is cheap from a junk yard in the last 10 years in my experience.

It's my observation that 1 1/4" for filler line is not that common, I see a lot of 1 1/2 and larger.
 
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I just use fuel rated hose. Both for oil coolers and the PCV system catch cans. But I use one piece of heater hose as a size adaptor as the smaller 3/8" fuel hose slips inside a 1/2" heater hose and then to the 12mm intake nipple. This 1/2" piece gets really hard but that actually helps the seal, not any flexing to speak of.
 
For the million'th time, 3/8 hose is one thing. But filler-neck hose is another. In terms of availablity it seems. For me. Especially for 1.25" ID. But generally the price is krazy, in Kanada, and even in the US it's like $1.25 AN INCH.

Part of my metal fuel filler neck got too rusty, the last foot of it, and the vapor return pipe that ran beside it had disintigrated (2004 Chrysler 300m). There some sort of 10 mm hard plastic line that runs from near the tank to the engine compartment, I will hook onto that with some ordinary 3/8 line and connect to stub coming off the filler neck. Why does this line need to be gas compatible? It will never see liquid gasoline, only vapor, do I care if it takes 10 years to rot? For the fill line I've got a 3 foot piece of expensive rad hose, reinforced with something on the outside like hockey tape, can probably take 200 psi, almost 1/4" thick, will take years for gasoline to eat it, will only see gasoline when I put gas in the car, what's the big deal with that?
 
You can use vinyl clear hose, it's not super expensive. It will turn hard and yellow after a few months but it takes many years for it to rot out.
 
Rock Auto has a 3' piece of fuel filler hose for 44.76. I sure wouldn't try using hose not rated for fuel.

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