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Fuel lines degrading with biodiesel - I learned something

BadDog

BadDog

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I recently learned that biodiesel degrades standard gas/diesel fuel hose very badly. I also read that I should look for "R9" rated hose to avoid issues. I had no idea...

As it turns out, "R9" is actually "SAE 30R9". And most parts houses carry this as common "fuel injection" hose. I called my local Advance and talked to the manager who looked up and confirmed that standard gas/diesel fuel hose does say "not safe for biodiesel", and the SAE 30R9 lines specifically says "safe for biodiesel".

I have no idea if I'll ever run B10+, particularly since you can't get it anywhere in N Phx (to my knowledge). But just in case, I bought SAE 30R9 lines to replumb both of my 6.2 vehicles...
 
Most fuel at the pump is a biodiesel blend. Any blend that's B20 or less legally doesn't have to be labeled at the fuel station.
 
All the more reason to avoid the standard diesel rated fuel lines on any diesel. Like ethanol in gas, there's just no way to avoid it.
 
depends on your state...normal diesel is B5....B20 up here is .50 cents less a gallon and anything B6 or higher has to be labeled as such..you can't call it diesel...No one runs it for the exact reason the OP stated.
 
PTFE hose is also safe for biodiesel and E85. Its virtually inert to all chemicals and solvents.
 
Do you have a good source for PTFE hose suitable for fuel lines? I know it's good stuff, but mostly recall seeing that in terms of braided hose. A quick search turned up some unbraided PTFE 3/8 hose for just over $5 a foot, but that's a bit steep compared to the "R9".
 
You can find it for $3 / foot if you look around. I usually just get it at Summit Racing but I see it on ebay for the cheaper price and sometimes they offer the -6AN with ends too. I use it for everything now. My fuel lines, hydroboost lines, etc. It has a very high burst rating. Its so nice when you can just unscrew the line instead of having to cut it off a barb fitting so very trail friendly. Plus the stainless steel sleeve protects it from rocks or something cutting it. Worth every penny IMO.
 
red EOD said:
Most fuel at the pump is a biodiesel blend. Any blend that's B20 or less legally doesn't have to be labeled at the fuel station.
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I don't know what the law is in California but most places don't say biodiesel but I know none have straight diesel.
They range from b5 to b20.
Some of the big truck stops now will say b20
 
I'm not sure how the percentage rates rate will affect the rate of degradations, but it sounds like anyone who bought the common "fuel hose" is likely to be having problems with those lines within an unexpectedly short time. And I also expect that most people would just assume the quality of the hose was the problem as opposed to the (unlabeled and unexpected?) biodiesel fuel content. That would be a very easy mistake to make.
 
I think this is why most vehicles went to using that hard nylon plastic fuel line ,hose quality is iffy,today you never know how good a hose is with so much made in china and other countries ..they aren't known for high quality rubber ..
 
BadDog said:
I'm not sure how the percentage rates rate will affect the rate of degradations, but it sounds like anyone who bought the common "fuel hose" is likely to be having problems with those lines within an unexpectedly short time. And I also expect that most people would just assume the quality of the hose was the problem as opposed to the (unlabeled and unexpected?) biodiesel fuel content. That would be a very easy mistake to make.
Click to expand...
Well thank you for bringing that up because I am finishing my engine transplant and I will make sure to check or replace all rubber hoses with known proper ones
 
For what it's worth, I used a motley assortment of hose types when replumbing my '83. Transmission cooler hose, cheapie rubber hose, cheapie plastic tubing, etc. I didn't have any issues with it in the last 8 years, but I may have just gotten lucky. My more recent vehicles have gotten 100% fuel-rated hose. Some high pressure injection hose, some low pressure non-injection hose. None of which carried any indications of biodiesel compatability (or lack thereof).

Who knows? :dunno:
 
I first ran across that when searching for other information, and stumbled onto a post about biodiesel damaged fuel lines showing clear damage with quite obvious ballooning and distortion. That got my attention, so searched some more on that topic to find numerous folks with common "fuel rated"hose very degraded in a matter of a couple years. And not just those running B100. For no more than it costs extra, I'm going to play it safe with the "fuel injection" hose.
 
One warning about some "fuel injection" hose--some I've seen and tried using,has a blue vinyl type inner liner,I'm not sure what the brand was,maybe Dayco or Gates--and it is a bitch to get on a fitting without that lining just getting shoved up inside the hose,instead of going over the barb fitting--it'll make a nice clot or blockage and cause a lot of grief..like it isn't bonded to the inside of the hose,it is a separate tubing..(but you cant yank it out either--I tried!)..

My friend got so frustrated with that stuff he tossed the remains of a 25 foot roll in the rubbish--me being Mr.Frugal and hating to see anything good go to waste,took it home,and I soon had the same issues when I went to use it on lawn tractors..

They have other types of hose rated for fuel injection that do not have that blue vinyl liner in it...the "best" stuff I liked was the hose with a woven fabric like cover,that was used on many VW's back in the day..

Transmission cooler hose is rated for hot oils,so I'd assume that would hold up well with biodiesel..its not cheap or even readily available at all parts stores though,at least not around here..most places want to sell you a 25 ft roll if they stock it,or pre cut lengths that usually aren't long enough..
When I worked in the junkyard I saw all kinds of cobbery--one car that we hoisted up on the forkloader to pull a transmission out,had the entire fuel line from the tank to the engine replaced with that clear vinyl hose with the cloth reinforcement in it,like you see on the dish sprayer on a kitchen sink!..:eek:
The metal line had rusted,so someone just bought about 12 feet of that hose at Home Depot and clamped it over the ends of the metal tubing at each end of the car..and ran it dangerously close to the exhaust system,only had zip ties holding it to the remains of the original metal tubing in a few spots!..the hose was all hard and yellow,felt like it would snap if you bent it-but it didn't leak !..

I also saw an old Ford pickup come in,that had garden hose for heater hoses..looked like they were on it for years too!..I once used a hunk to get home in my old Buick once--but removed it as soon as I made it home..
 
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