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  • Repairs


    I am new to the site. I have not purchased a CNG vehicle. My mother has a bi-fuel Ford truck and so does a guy we work with. I currently own a very nice Corrola that I purchased from sister last June. It is very good condition, but because of rising gas prices I was thinking about selling it and getting a used CNG. I can't afford a new one. However, in reading many of the threads I have noticed that the used cars seem to need a lot of expensive repairs. I added up what I would pay a year to fill up my car with gas if gas was as much as $12.00 a gallon, and one of the CNG repairs would cost just as much as the gas does a year. I was wondering how many of you have had to repair something on you car? How long have most of you had your cars? When you repair something, how long does the reapair last. I don't want to put what I would spend on gas into repairs because the savings on CNG would be pointless. Your help is appreciated.


  • #2
    Re: Repairs

    One of the problems with this site is you are going to hear from those needing help such as yourself, while there are many others registered here that you will not hear from. I have 4 CNG vehicles and have had no CNG related repairs in the last 12 months for example. So like any other used vehicle, it will be pot luck, you can get good ones and bad ones, and sometimes surprises whether it be a NGV or regular used vehicle, you shop for the best you can get and then hope for the best and cross your fingers.
    My best experience with used AFV's have been with factory Chevy's, I've had 3 and still own 2. Ford's are ok but seem to be really expensive to take care of once they get higher miles on them, especially dual fuel. Dedicated NGV's have less equipment to maintain so the odds are better too, but your driving range may be limited.
    Dave Clement


    • #3
      Re: Repairs

      leechlover (?)

      I would add that from a theoretical point of view, you should expect a longer engine life running on CNG. The higher octane (120-130) translates to a slower burn rate and a longer, smoother power stroke. The flame front follows the piston down into the cylinder further resulting in less pounding on the bottom end main and rod bearings.

      I've got over 250,000 miles on a Ford 302CID that I guarantee wouldn't have gone that far on gasoline.

      So, use the forum for other opinions and consider us a source of information and support.

      Best regards,



      • #4
        Re: Repairs

        I don't have experience with the bi-fuel vehicles. I have a 2002 Honda Civic GX (dedicated CNG). It has about 82,000 miles and the only running gear trouble I have had is the CVT transmission. It needed to be rebuilt at about 70,000. It was covered under my extended warranty. I have had no CNG related repairs.

        Of course, you may have trouble finding one now.


        • #5
          Re: Repairs

          I have had my car for a year now and the only thing that went out on it was a fuel injector. Other than that I have had no problems with my Civic GX.


          • #6
            Re: Repairs


            Many of the CNG vehicles are basically reliable (particularly dedicated CNG), but they have the normal repairs of any used car to the non-CNG components. Also, other than the Honda Civic, most are American cars with overall reliability and cost of ownership not approaching that of a Corolla. The main thing that I think you should be aware of is that you run the risk with CNG that at any time you may have a $1,000+ repair. These can be things like a like a unique main computer or fuel injector driver going bad and the part is hard to find and expensive, or the dreaded compuvalve, or as simple as a piece of road debris damaging a CNG tank under the vehicle (could be $2,000+ in that case). So, you have to do a very honest calculation of fuel savings versus purchase and repair costs over a few years. Sounds to me like you already have a pretty good bird-in-the-hand with an fuel efficient, reliable Corolla.

            Back in 2000, or even 2006, when you could find an older low mileage CNG vehicle that no one wanted for $1,000 to $2,000, you could afford to roll the dice on repairs. But CNG vehicles are selling at a high (many would say unreasonable) premium now with gasoline prices climbing and the high demand for CNG vehicles in Utah and elsewhere.



            • #7
              Re: Repairs

              Having bought and sold a numerous amount of CNG vehicles I learned a couple of pointers the hard way.

              1- If you are purchasing a bi-fuel Ford make sure that the vehicle falls within the 8 year 80,000 warranty period. The compuvalves and regulators are really expensive. I have had to replace about 40% of the compuvalves on Ford's that I have purchased to resell. And yes, I paid for 2 of the 10 out of my own pocket. About $2700 each. Also if you are purchasing a Ford that has approximately 7+ years on it you better plan on paying for a tune up with plugs and o-rings. It will run approximately $1000 at a Ford dealer or $650 at a good CNG specialty shop.

              2- A super low mileage Ford bi-fuel can often have compuvalve troubles. Bi-fuel Fords are not happy if they sit unused for long periods of time. If you find a 2000 Ford Contour with 14,000 miles on it at a GSA auction or an 2000 F-150 with 17,000 miles don't be so anxious to join in the frenzy of bidding unless you are sure that 8 years will not expire until after you have had the vehicle for a few months. Don't assume that others bidding at an auction know any more than you do.

              3- Ford bi-fuel regulators are about $1300 to have them replaced. If the Cng vehicle does not run really smooth, don't buy it.

              4- Chevy Cavaliers are great cars. 2003 and 2004 have the ECOtech engine. This is a great engine.

              5- If the cng tanks have any scratches deeper than about .030 stay away from them.

              6- If the seller tells you that the CNG system has been jerry rigged to only run on gasoline or only on CNG stay away from it.

              7- If the CNG vehicle is older than 15 years, realize that the CNG tanks most likely have expired.