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Fuel Tanks - Steel Or Polyethylene?

Discussion in 'Early CJ5 and CJ6 Tech' started by Oldpappy, Oct 5, 2021.

  1. Oct 5, 2021

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
    Feb 8, 2021
    I have bought two CJ replacement gas tanks, both reproductions made of steel, and I have had problems with leaks on both of them.

    The one I installed in my CJ2A leaked around the bung for the fuel line fitting. I drained and pulled the tank and put a light inside. There was a big gap between the bung and tank. I fixed that with some Permatex sealer made for gas tanks.

    The one I installed in my CJ5 seemed okay at first, no leaks for the last couple of months but the tank was only about half full during this time. Last week I drove it into town and filled it up at the gas station. By the time I got home the floor board was covered in fuel. It is leaking around a seam. I can fix it, but it really bugs me these things are no better than this.

    I am now considering a plastic tank with a pickup on top. I see one out there made in USA, "MTS" brand, which is made of 1/4" High Density, Cross-Linking Polyethylene.

    I don't like the idea of a plastic tank, but I like it better than a crappy foreign made steel tank that leaks.

    Anyone tried one of these Poly tanks ?

    I am also considering an aluminum fuel cell mounted in the cargo bed, but leaning more towards the under seat plastic tank to leave more room for gear in the bed.
    Alan28 likes this.
  2. Oct 5, 2021

    RATTYFLATTY I think you need a little more throttle

    Central MN
    Oct 23, 2007
    This is why 50+ year old nonleaking used gas tanks have value.
    Alan28 likes this.
  3. Oct 5, 2021

    EDDY ARNOLD Member

    Apr 6, 2021
    Have MTS plastic tank 6 months old no leaks
    Downs likes this.
  4. Oct 5, 2021

    jeep2003 Well-Known Member

    Upstate NY
    May 30, 2006
    I had two go bad in my 2a in a year. that was 20 years ago. got a poly tank and its been great. Then got one for my cj5 in 08 and its been good to. The only annoying thing is the caps dont fit that great. you need an original cap for sure. Routing the lines up and over isnt that bad. Youll also need to fuss with the hold down clamps for the sender to get a good seal on it. But after installation iv never had a problem. I know alot of people complain about that.
  5. Oct 5, 2021
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
    Nov 12, 2009
    The new metal tank I got for my Jeep. Coated the inside of the tank before installing it.
  6. Oct 5, 2021
    scott milliner

    scott milliner Master Fabricator

    Seattle Wa.
    Dec 17, 2002
    I found a shop that could repair the leaks I had. They also were able to coat the inside and outside of the tanks to prevent leaks and rust. Could look into it.
  7. Oct 5, 2021

    SFaulken Active Member

    Bellevue, WA
    May 24, 2011
    OEM's switched to plastic fuel tanks for multiple reasons. That they don't rust is just one of them. I'd probably replace mine with plastic, if it needed replacing.
    fhoehle and ITLKSEZ like this.
  8. Oct 5, 2021

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
    Feb 8, 2021
    After reading these responses and doing some more internet research I decided to go ahead and try one of those MTS poly tanks. I ordered one from Midwest a few minutes ago. The tank is supposed to accept the standard sender unit, which is a plus, and it sounds like the only modification I will need to do is route additional fuel line to the pickup on top.

    While I am sure I can find the leak in the reproduction steel tank and seal it, I find the construction questionable enough that I would worry about the thing springing a leak at another place later on, and I don't want to be far away from home with a floorboard covered in gasoline that is dripping onto the exhaust pipe.
    Last edited: Oct 5, 2021
    fhoehle, SFaulken and Vanguard like this.
  9. Oct 5, 2021

    Jeepenstein Me like Jeep..

    North Central FL
    Jun 15, 2003
    I'd be comfortable with a good poly tank. No rust is a bonus.
  10. Oct 5, 2021

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Aug 10, 2003
    Suspect the poly tanks are more crash-worthy too.
  11. Oct 5, 2021

    Cj5dale Member 2023 Sponsor 2022 Sponsor

    Knoxville, Tn
    Aug 19, 2021
    I have one and it works great. No leaks and no chance of rust.
  12. Oct 5, 2021

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
    Feb 8, 2021
    Noticed they make a version of this tank to use under the passenger seat. Of course that would require removing the tool box and fabrication of a new seat frame, but I have been thinking of doing that anyway.
  13. Oct 6, 2021
    Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

    I live South of...
    Dec 2, 2014
    I bought a plastic tank for my Jeep but sent it back because the filler neck was not in the center of the filler neck hole in the body. I think it was from KW and they didn't want to exchange it until I told it didn't fit correctly, they agreed that it was a factory mistake and traded me a steel tank in exchange for the plastic tank. It all came out good, the steel tank works fine and everything worked out as far as fuel gage and fuel line hook up. I needed the fuel line to come out the bottom of the tank, I put a fuel drain on the bottom so I cane empty the tank or get gas without a siphoning hose. Good luck.
  14. Oct 6, 2021
    Michael Wedin

    Michael Wedin Member

    Sweetwater, TX
    Mar 20, 2020
    With a new tank , gas tank sealer would be a good option. I did this on my old tank and worked great. I have always heard "Bill Hirsch tank sealer" is the best. Doesn't break down with gas we have to day.
  15. Oct 7, 2021
    David Allen

    David Allen New Member

    Carson City Nevada
    Jul 10, 2020
    I have used both Bill Hirsch and Eastwood sealers. If you get them cure befor use the are both very good.
  16. Oct 9, 2021
    Rust Ranger

    Rust Ranger Custom Made Antiques Tomorrow

    Nov 18, 2020
    I have inherited a Poly Tank in the bucket of bolts. Not as classic looking of course but quite durable and with the improvement of a top port and sender a great improvement. Only make sure you in-line filter as I had lots of plastic shards show up upon use. Thought I’d get an replacement metal tank but after reading this I’m pleased. Got enough other shaky stuff going on to add to the task.
  17. Oct 9, 2021
    AC Bill

    AC Bill New Member

    Vancouver Island BC
    Sep 18, 2021
    Summit Racing Equipment has a slurry of fuel cells available. They are designed to be tough as they are for race vehicles. You can get them in aluminum, plastic, steel, and steel with a bladder. Some include sender units, but I'm not sure what ohms the stock Jeep gauge are, so they may have to be switched out, or a different gauge used.

    https://www.summitracing.com/search...er=Ascending&keyword=fuel cells&kr=fuel cells
  18. Oct 9, 2021

    Alan28 Well-Known Member 2022 Sponsor

    Châtillon en...
    Oct 21, 2012
    It seems that new materials are good to keep fuel. On my John Deere lawnmower it is plastic and transparent, very useful.
  19. Oct 9, 2021

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    York, PA
    Mar 6, 2004

    Vacuum the tank out before installation.
    Rick Whitson likes this.
  20. Oct 22, 2021

    Oldpappy A.C. Fults - Curmudgeon at large 2022 Sponsor

    East Tennessee
    Feb 8, 2021
    The MTS plastic fuel tank was delivered by FedEx on October 14th, but unfortunately they delivered it to the wrong address. After filing a claim with them they did find it, and put it on my porch Wednesday.

    I installed it yesterday, with a filter mounted on the backside of the floor riser. It fit perfectly with the fill neck centered in the hole. Cap is a little difficult to get on, but seems to fit snuggly. While I would prefer a metal tank if I could get a good one, I am pleased with this tank. The material is about 1/4" thick, and it seems very sturdy.

    I put some gas in it and drove it into town to fill it up the rest of the way without any problems. Everything was completely dry when I got home, so no leaks.

    When I first tried to register this Jeep DMV said I would have to drive it in for a VIN verification.

    I had plenty of paperwork from the Estate of the owner showing a complete history, but because it had not been registered since 1968, they required I bring it in. Now I am ready to go back to DMV.

    I do not intend to drive an unregistered vehicle 50 miles, so will trailer it to a lot near the DMV and drive it into there as there is no place to park a trailer.
    Last edited: Oct 22, 2021
    Jw60, Fireball, timgr and 1 other person like this.
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