Corrosion and fuel blockage in Ford diesel fuel tanks

A. I strongly suggest that anyone interested in this subject view the description of changes in sheet steel plating for fuel tanks described in a patent summary at:

http://www.patentstorm.us/patents/6673472/description.html

US Patent 6673472 - Rust preventive carbon steel sheet for fuel tank having good welding gastightness and anticorrosion after forming

Summary:

1. Aluminum-silicon sheet steel plating commonly used now in fuel tanks is much more likely than earlier plating materials (lead-tin and then zinc-chrome) to crack because aluminum is more brittle than the other materials.

2. Formic acid resulting from fuel deterioration invades the initial crack(s) resulting from vibration and/or impact, corroding under the plating and causing it to separate from the sheet steel.

3. The result can be detachment of much of the tank lining as flakes, causing fuel system blockage and fuel starvation.

(Note: My earlier speculation that oxygenated gasoline was an underlying cause may not be well founded.)

This is a followup to my May 12, 2008 post on fuel tank inner plating failure in 83 and 87 Subaru DL wagon, resulting in fuel filter clogging and fuel starvation. After the 87 fuel tank contamination was cleaned out by thorough steam cleaning a month ago, the 87 has run fine. In a couple of days I'll take it in for change of fuel filters, and keep the old one for analysis (I forgot to tell the tank cleaners to keep samples) in case there is still some residue in the tank.

Additional notes:

1. A friend said the same symptoms are occurring in her guy's 1999 Lexus: runs fine when standing still, but bucks and kicks from fuel starvation when going uphill and at higher speeds. We will take it in for fuel filter check when her guy returns from travel.

2. The occurrence of these fuel tank plating failures, in Anchorage, appear to coincide to a great extent with fuel oxygenation additives required by the EPA here from 1992 to 2004 (MTBE 1992-3, ethanol 10% 1995-2004). In 2004, Anchorage attained the EPA standard for carbon monoxide (CO) and ethanol was discontinued. Is it possible the oxygenated gasoline, unanticipated by the Japanese fuel tank manufacturer(s), attacked the plating lining the fuel tanks?

3. Finding out what the Subaru fuel tanks were plated with appears hopeless: a Japanese supplier to Fuji Heavy Industries (maker of the Subaru) more than 20 years ago. Our 96 Outback does not have the symptoms. I believe it arrived in Alaska from Seattle about 2004 and avoided the 10% ethanol fuels here. Seattle went off oxy fuel in 1996; see http://www.eia.doe.gov/emeu/steo/pub/special/oxy2.html. To this vehicle's tank was not exposed to oxy-fuel.

4. We will save contaminants from the Lexus for analysis. If my 87 Subaru fuel filter is picking up some remaining liner particles, perhaps we can analyze that for zinc or aluminum.

5. Lining failure with diesel is interesting, and there is some mention, in this string, of additives in recent years which could not have been anticipated by the fuel tank manufacturer. Has anyone identified specific additives which may be causative and what is their status in diesel today?

This is partly a restatement of my May 29 post so I will shorten it up:

See the following patent description for a more complete explanation for the failure of the aluminum plating on carbon steel fuel tanks (no evidence stainless tanks have this problem):

http://www.patentstorm.us/patents/6673472/description.html

US Patent 6673472 - Rust preventive carbon steel sheet for fuel tank having good welding gastightness and anticorrosion after forming

Summary:

1. Aluminum-silicon sheet steel plating commonly used now in fuel tanks is much more likely than earlier plating materials (lead-tin and then zinc-chrome) to crack because aluminum is more brittle than the other materials.

2. Formic acid resulting from fuel deterioration invades the initial crack(s) resulting from vibration and/or impact, corroding under the plating and causing it to separate from the sheet steel.

3. The result can be detachment of much or all of the aluminum plate tank lining as flakes, causing fuel system blockage and fuel starvation.

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If you are experiencing easy engine starting and running while the vehicle is standing still, followed by bucking-kicking and fuel starvation after the vehicle is in motion and the fuel sloshes around:

1. IMMEDIATELY have the fuel filter removed and replaced.

2. You should find aluminum flakes clogging the fuel filter. Keep the filter as evidence until you resolve your warranty or insurance claim. Do not let it out of your sight unless it goes to your attorney or advocate.

3. Siphon a lot more of this material from the bottom of the tank (as close as possible to the fuel intake tube screening) into several clear, clean glass bottles or jars so as to have plenty of evidence which can go with your claim; but don't give up the fuel filter and a few of the jars as they are evidence.

4. Have a reliable witness observe the siphoning. Both of you write statements and have them notarized.

5. If you need to use the vehicle, have the fuel tank interior vigorously cleaned and immediately refilled with fuel.

6. Replace the fuel filter after a month and inspect the filter carefully. If it's clean, the tank lining may have completely detached, but keep the tank full to prevent rusting of the exposed carbon steel. Replace and inspect the fuel filter at least annually -- they are cheap.

That's it in brief. Good luck with your claim. Be assertive, wave your evidence in front of their eyes, write polite demand letters and keep a file. In the RE: line number them FIRST DEMAND letter, SECOND DEMAND letter etc. so you can document refusal to respond to your claim.

More on possible class actions later. I am willing to receive direct e-mails if you have questions.

A. I strongly suggest that anyone interested in this subject view the description of changes in sheet steel plating for fuel tanks described in a patent summary at:

http://www.patentstorm.us/patents/6673472/description.html

US Patent 6673472 - Rust preventive carbon steel sheet for fuel tank having good welding gas-tight-ness and anticorrosion after forming.

Summary:

1. Aluminum-silicon sheet steel plating commonly used now in fuel tanks is much more likely than earlier plating materials (lead-tin and then zinc-chrome) to crack because aluminum is more brittle than the other materials.

2. Formic acid resulting from fuel deterioration invades the initial crack(s) resulting from vibration and/or impact, corroding under the plating and causing it to separate from the sheet steel.

3. The result can be detachment of much of the tank lining as flakes, causing fuel system blockage and fuel starvation.

(Note: My earlier speculation that oxygenated gasoline was an underlying cause may not be well founded.)