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Regular Gas in a diesel

Discussion in 'Mechanic and Repair' started by rbriggs, Nov 5, 2005.

  1. rbriggs

    rbriggs LawnSite Member
    Posts: 106

    One of the other franchises in our area had an incident recently where an employee accidentally added 5 gallons of regular gasoline in their diesel trucks. They were advised by their mechanic to keep it full of diesel for a while and it should dilute the gasoline. Didn't sound exactly that easy to me, but wanted to get someone elses opinion.
    This is exactly why we lock out the regular gas on our key pump system. The keys on the truck rings only allow the guys access to the diesel.
  2. jim dailey

    jim dailey LawnSite Senior Member
    Posts: 614

    OK, there was a post about this not too long ago. Only 5 gallons, you should be safe. The mechanic is right, it will dilute. It happened to me about 15 years ago. I was driving a Ford F-350 Wrecker, on a trip to Worcester and back, towing a car. I filled-up in Milford, and headed out on Route 146. Hit the Highway and the pinging started. I couldn't figure it out. Went all the way to Worcester and back, then figured it out. The kid at the pumps put gas into the disel tank. We emptied the rest of the tank that night, and it ran fine for the next couple of years, until it was involved in an accident. The engine had just been rebuilt, with new crank bearings. They were fine. My best guess would be that 20-25 gallons of gas went thru that "new" motor, and things were fine in the end.
  3. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Any gas in a diesel is not good. The tank should be drained and refilled with diesel.
  4. grass_cuttin_fool

    grass_cuttin_fool LawnSite Gold Member
    Posts: 3,503

    Yes I would drain the tank. I was a mechanic for 20 years and our drivers allways had the fear of there fuel jelling in the winter and some would add gas instead of buying fuel conditioner. Gas is an explosive and diesel is a combustable. What can happen is the tips on the injectors can get blown away by the gas exploding instead of burning like the diesel does. Also its an old myth that gas makes a diesel have more power and that is bull, diesel fuel has alot more BTU's than gas does. Back to the subject......... Ive seen both senario's where people done nothing and seen where the tank was drained......if it were me I would drain the tank. What size diesel tank was it by the way?
  5. Brianslawn

    Brianslawn LawnSite Silver Member
    Posts: 2,004

    it'll probably start running faster and faster til it blows. thats what a mechanic told me about gas in diesel. use propane for a nos like boost on deisel engines.
  6. grass_cuttin_fool

    grass_cuttin_fool LawnSite Gold Member
    Posts: 3,503

    actually the performance is less and less with gas because of lower BTU's than diesel fuel when the fuel burns. And if the tips blow of the injectors then you do have a mess because when you do replace them, then you dont have a rebuildable core and that means even more $$$
  7. joe stihl

    joe stihl LawnSite Member
    Posts: 35

    I topped off an almost empty tank with gas. The truck had no power. Just putting the truck in drive would kill the engine, but then it would start right back up. Long story short, the fuel distributor filled up the stations diesel tank with gas and I got a new injection pump.payup
  8. rbriggs

    rbriggs LawnSite Member
    Posts: 106

    Thanks guys for the info. i will pass it along.
  9. fixer67

    fixer67 LawnSite Silver Member
    Posts: 2,100

    I posted this before on another thread about this same thing. Here it is again

    I seen this happen my self. It was some years back. I was working at a construction site. One crew was using a jackhammer powered by a Ingersoll-Rand screw compressor. It was running low on fuel and this new kid put GASOLINE in it. No one seen him do it or paid him any attention. Any way when it got to the gas it started over-speeding big time. The rev-limiter did not kick in. The old man tried to shut it off. The RPMs were off the scale. It sounded like an F-4 taking off. People started running screaming it was going to blow. As this was going on I was sitting on a log at the edge of the parking lot eating my lunch. As people ran past me I just rolled down the hill backwards. Not really sure if I was pushed or not. As I was getting up after rolling about 10 foot down the hill I heard the compressor blow. Then I heard something falling around me. It was parts of the compressor. A piston just missed be by a foot or so. There was little left of the compressor, about all that was left was the carrier frame it sat on. That poor thing must have being doing 10,000 RPMs when it let go. So while 1 gallon in 30 may not do it much harm (as others have said) I can tell you first hand that 100% pure gasoline in a diesel will do some real damage. The real sad part about this was the compressor was a rental unit with only about 20 hours on it. I hope they got the rental insurance.
  10. Brianslawn

    Brianslawn LawnSite Silver Member
    Posts: 2,004

    thanks fixer. thats similiar to stories ive heard.

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