View Full Version : Does diesel fuel go bad?


wormwood
09-12-2010, 07:53 PM
I have a diesel lawn mower.

Can you keep diesel fuel in a plastic can over the winter or does it "go bad" like gasoline will?

Can you put Sta-bil in it? Something else to keep it fresh?

Thanks

Art From De Leon
09-12-2010, 08:10 PM
Buy some diesel fuel treatment at Wal Mart, and fill the tank to the top to keep out moisture. If you can find some biocide, the treatment may already contain it, so much the better, diesel will stay fresh for years.

wormwood
09-12-2010, 08:16 PM
Thanks for the advice!

wafrederick
09-12-2010, 08:43 PM
Diesel fuel can gel and that is bad.There is an anti gel additive sold at some parts stores

e-tek
09-12-2010, 08:48 PM
Todays fuels are CRAP! Especially the so-called "clean" fuelswhich deteriorate WAY faster than fuels made 20 years ago, especially oif they contain derivatives of methyl alcohol and ethyl alcohol. I've seen gasoline have shelf life as little as a month--especially if subject to heat and moisture.

Diesel fuels may be a little better, but not much. Most all diesel fuel, will last only from 3to 6 months. But it varies widely - which is where the problem can lie. Read on.

Here's a quote from an internet watchdog group: "Recently we tracked a diesel fuel produced at a refinery in Texas to its final destination in Florida. When tested at the refinery the same day it was produced, the fuel barely met the specification for stability. After being stored, pumped into a coastal tanker, offloaded at Port Everglades, stored again, delivered to the fuel jobber, and finally to the customer, 23 days had passed. Again the fuel was tested.This "fresh" fuel now tested out of spec. "

In part, this has to do with new processing techniques developed by refiners in recent years. These fuels are often far less stable than the conventional "straight run" fuels we had before. Another issueagain is those Methanol and any ethanol products, which degrade much faster than straight petroleum fuel. One oil company survey indicates that at least 50 percent of the gasoline sold today is substandard.

So I guess the bottom line is not to trust any fuel over the long run. If you're gonna store it - or it's gonna sit - more than a month, treat it. Lots of tanks may be OK, but then you'll get the one that spent 60 days in transit and was degrading fast to begin with!

december45
09-12-2010, 10:14 PM
i have kept diesel in plastic containers over the winter with no problems, however we have pretty mild winters, no really hard freezes.

Racer_X
09-12-2010, 10:54 PM
You guys are making me feel guilty. I've had the same fuel in my deuce and a half for over two years. When I drive it (not often enough, obviously) it runs just fine, though.

Scout Driver
09-12-2010, 11:15 PM
Buy some diesel fuel treatment at Wal Mart, and fill the tank to the top to keep out moisture. If you can find some biocide, the treatment may already contain it, so much the better, diesel will stay fresh for years.

Good advice here from Art. Stanadyne is a good brand that we use here on the farm. Excellent product. We run a soy-biodiesel blend that is more apt to go bad than straight diesel fuel. Never had a problem when using Stanadyne in the fuel.

Scott

onewaydave
09-12-2010, 11:47 PM
Huh! I have diesel trucks and tractors. If I don't forget to put additive before the first freeze, I pay bigtime. Have to change the filters, water extractors, warm the whole fuel system and bleed the injectors. PITA in sub zero weather with 20 mph winds in the middle of the corn field. One would think I'd learn.

If I do remember to put additive, I've never had a vehicle fail to start due to fuel reasons. One tractor hadn't been run for 2 years and cranked up like I'd shut it off yesterday. This is pretty typical for around here (midwest US).

Gasoline is a whole other nut in a vise. IME.

The major bad about modern diesel is the low sulfer content. No lubricity. Burns up pumps. Most additives have a lubricant and some put a qt of 20 w non-detergent motor oil per 30 gal or so to provide lubricity.

Notice that retail dealers change between diesel #1 and #2 between winter and summer, that's for the anti-gel properites but not the lubricity.

Deisel has the possibility of growing some bacteria that will clog up the system. Probably worse if it sits for long periods of time. I just haven't had that problem.

Dave.

HOTFR8
09-13-2010, 12:16 AM
You guys are making me feel guilty. I've had the same fuel in my deuce and a half for over two years. When I drive it (not often enough, obviously) it runs just fine, though.

I have the same fear with my T Roadster. I had to use some Start Ya Bastard (like Aero Start)
http://www.nulon.com.au/files/images/aerosol/SYB/thumbs/SYB-thumb.jpg
yesterday due to the fact it has not been out for so long. I always add fuel set and octane booster to the fuel. Fuel set should protect it and I always add fresh fuel when I can.


I'm getting confused by the two different topics :headscrat

http://www.garagejournal.com/forum/showthread.php?t=75191

http://www.garagejournal.com/forum/showthread.php?t=75181

Both with a lot of information. :thumbup:

onewaydave
09-13-2010, 01:11 AM
I too, am getting confused as a poster to the other diesel thread states.:headscrat

http://www.garagejournal.com/forum/showthread.php?t=75181

Stick, a poster at GJ states that sulfer has nothing to do with lubricity and that it is the process of removing the sulfer that lowers the lubricity. Humm. Much different than what I have heard and read, but worth investigation.
:confused:
I do note that machinists use cutting oil with high sulfer content for machining steel and when I asked (on machining forums) about using some hydraulic oil that is not good enough of hydraulic systems I was told that it would not be a good choice because of the low sulfer content and poor lubricity.

So, thanks to Stick and others, I will have to read up on this.:thumbup:

I'll stand by my other statements (until sonebody shoots them down).

And in the thread (looks and points up) there is a test of the lubricity of several commercial products and some home brew treatments that all diesel owners should read.

Dave.

D9H 90V
09-13-2010, 01:18 AM
Diesel will go bad, it will go bad before it gels, you dont want either, it does take a long time for it to go bad though, I would run the tractor almost completly out of fuel but not all the way, then as soon as you are gonna need the tractor add fresh fuel and get it started, once its started and run for about an hour change the fuel filter(s) and everything should be fine

Stick
09-13-2010, 02:13 AM
I too, am getting confused as a poster to the other diesel thread states.:headscrat

http://www.garagejournal.com/forum/showthread.php?t=75181

Stick, a poster at GJ states that sulfer has nothing to do with lubricity and that it is the process of removing the sulfer that lowers the lubricity. Humm. Much different than what I have heard and read, but worth investigation.
:confused:
I do note that machinists use cutting oil with high sulfer content for machining steel and when I asked (on machining forums) about using some hydraulic oil that is not good enough of hydraulic systems I was told that it would not be a good choice because of the low sulfer content and poor lubricity.

So, thanks to Stick and others, I will have to read up on this.:thumbup:
I'll try to explain as best as I can, but I'm not an engineer, I'm just a mechanic who spends entirely too much time reading trade journals and whitepapers.

Hydrocarbons form the basis of crude oil pumped from the ground. Refining is the process of turning those hydrocarbons into usable products. A hydrocarbon is made up of chains of molecules, and the length of that chain is part of what determines what kind of petroleum product. Think of it this way, crude oil is the longest chain, and something like natural gas is the shortest chain. The longer the chain, the thicker the byproduct of refining (and the higher the viscosity is). Also, longer chains have higher boiling points (which is how refining works, they essentially boil the crude oil until it separates).

You will note that in the other thread I stated:
Actually Sulfur is quite abrasive and has little to no lubricity. The problem with ULSD is the additional refining required to remove the sulfur, that's what reduces the lubricity of the diesel. Bio-diesel has little to no sulfur in the base oil, so the additional refining required with dino-oil is not required.

In order to refine the sulfur out of the petroleum, the hydrocarbons need to be split into smaller chains for the proper chemical reactions to take place to remove the sulfur. This is why machinists want high sulfur cutting oils, they are less refined than a hydraulic oil and as a result have a higher boiling point, in addition to being more viscous (thicker).

It's a completely different application than something like diesel fuel or hydraulic oil. Your hydraulic oil needs to be reasonably viscous to provide lubrication to moving parts in the pump, but at the same time be thin enough to move through stuff like valve bodies and ports. Diesel fuel needs to be refined even further, as shorter chains burn easier. This is why diesel was fine when sulfur levels were in the 500ppm range, but now with the 15ppm ULSD, it has lower lubricity.

Hope that helped.

CRTDI
09-13-2010, 02:45 AM
Huh! I have diesel trucks and tractors. If I don't forget to put additive before the first freeze, I pay bigtime. Have to change the filters, water extractors, warm the whole fuel system and bleed the injectors. PITA in sub zero weather with 20 mph winds in the middle of the corn field. One would think I'd learn.

If I do remember to put additive, I've never had a vehicle fail to start due to fuel reasons. One tractor hadn't been run for 2 years and cranked up like I'd shut it off yesterday. This is pretty typical for around here (midwest US).

Gasoline is a whole other nut in a vise. IME.

The major bad about modern diesel is the low sulfer content. No lubricity. Burns up pumps. Most additives have a lubricant and some put a qt of 20 w non-detergent motor oil per 30 gal or so to provide lubricity.

Notice that retail dealers change between diesel #1 and #2 between winter and summer, that's for the anti-gel properites but not the lubricity.

Deisel has the possibility of growing some bacteria that will clog up the system. Probably worse if it sits for long periods of time. I just haven't had that problem.

Dave.


Here is some interesting reading on diesel fuel quality and diesel fuel lubricity:

http://www.bosch-kraftfahrzeugtechnik.de/media/pdf/themenimfokus_1/FIEM_Common_Position_Statement_2009.pdf

http://www.arb.ca.gov/fuels/gasoline/meeting/2003/022003bosch.pdf

http://www.johnfjensen.com/Diesel_fuel_additive_test.pdf

onewaydave
09-13-2010, 04:18 AM
Stick and CRTDI, thanks for the replies. Yeah, I remember some of this stuff from inorganic chemistry, but I leave a disclaimer that I'm no engineer or chemist. I hope you are not up late just for this, I have to be up and am just passing the time learning something interesting.

From the ULSD wiki which is fairly well annotated.

http://en.wikipedia.org/wiki/Ultra-low_sulfur_diesel

Sulfur is not a lubricant in of itself, but it can combine with the nickel content in many metal alloys to form a low melting point eutectic alloy that can increase lubricity. The process used to reduce the sulfur also reduces the fuel's lubricating properties. Lubricity is a measure of the fuel's ability to lubricate and protect the various parts of the engine's fuel injection system from wear. The processing required to reduce sulfur to 15 ppm also removes naturally-occurring lubricity agents in diesel fuel. To manage this change ASTM International (formerly the American Society for Testing and Materials) adopted the lubricity specification defined in ASTM D975[8] for all diesel fuels and this standard went into effect January 1, 2005.[9] The D975 standard defines two USLD standards, Grade No. 2-D S15 (regular ULSD) and Grade No. 1-D S15 (a higher volatility fuel with a lower gelling temperature than regular ULSD).

The refining process that removes the sulfur also reduces the aromatic content and density of the fuel, resulting in a minor decrease in the energy content, by about 1%. This decrease in energy content may result in slightly reduced peak power and fuel economy.

The transition to ULSD is not without substantial costs. The US Government has estimated that pump prices for diesel fuel will increase between $.05 and $.25 per gallon as a result of the transition. And, according to the American Petroleum Institute, the domestic refining industry has invested over $8 Billion to comply with the new regulations.

ULSD will run in any engine designed for the ASTM D975 diesel fuels.

It is, however, known to cause some seals to shrink (Source: Chevron paper) and may cause fuel pump failures in Volkswagen TDI engines used in pre-2009 models. TDI engines from 2009 and on are designed to use ULSD exclusively; biodiesel blends are reported to prevent that failure (Source: HRCCC.org Biodiesel Best Management Practices).


From the Tier II wiki. A very light summary of some of the government regs that controll this discussion's subject.

http://en.wikipedia.org/wiki/Tier_(emission_standard)#Phase_2_-_2004_and_later

An interesting white paper on LSD, additives and lubricity from Standyne. It is somewhat dated (pre 1993) but may give the uninformed reader (like me) some background.

http://journeytoforever.org/biodiesel_stana.html

An interesting discussion and testing of lubricity and cetane improving additives in Diesel Power Magazine November, 2009. Scientists here may be able to pick at the methodology, but as a lifetime student of science, I'd say this is sure grounds for more testing (have you ever heard a scientist say that there were grounds for no further testing?)

http://www.dieselpowermag.com/tech/ford/0911dp_fuel_additive_test/index.html


A white paper on biodiesel and lubricity.

http://www.biodiesel.org/pdf_files/fuelfactsheets/Lubricity.PDF

Just some reading I came across tonight on the subject.

One day I might go around the county and ask old farmer friends to start up tractors/equipment that have been sitting for months-years to see if any don't run. Might be interesting. Not saying diesel doesn't go bad, just sayin does it still run.

Dave.

some zilch
09-13-2010, 05:07 AM
boy, it must be tough on places like hospitals and large office buildings to have to their diesel fuel for their huge generators going bad in 3 to 6 months.....

other than it gelling in the wintertime, diesel fuel keeps very well; especially if kept out of the sun (like not in transparent containers). my diesel genset runs just fine on 3 year old diesel

babzog
09-13-2010, 10:30 AM
So, Wally-world should have something to prevent gelling of the fuel? I was wondering the same myself as I've got a couple of (full) 5gal cans at home, plus a full tank in the tractor, none of which have had any additives put in. I've been wanting to treat it all with something to keep the fuel usable over the winter. Also wanted to keep it fresh - I always add sta-bil to a full can when I bring it home.

nate379
09-13-2010, 12:28 PM
I don't know where some of you guys get your info but it's interesting.

Diesel doesn't go bad like gas will, though it is hygroscopic and the moisture will cause algae growth after a while.

I am running stuff in my trucks right now that is about 8 years old. Funny thing is I have been getting better fuel mileage with it then "fresh" fuel.
My folks have a oil furnace for backup heat, they fill the tank once every 5-6 years.
(fuel oil... diesel.. same stuff.)

Over the winter will be fine!

s_ontario
09-13-2010, 05:36 PM
dealer tells me
gas starts to go bad after 30 days
diesel starts to lose BTU's after 60 days some say after 28 days #2 fuel starts to degrade

fourfeathers
09-13-2010, 06:08 PM
New trucks don't like old diesel. Old tractors are very forgiving, but look at the small amount of fuel they are consuming, by flow and by miles or hours.

nate379
09-13-2010, 06:29 PM
None of my stuff is that old. The oldest is a 95 and the newest is a 2010 (tractor)

HOTFR8
09-13-2010, 06:32 PM
Any one add a product called fuel set ? I am told this helps.