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diesel/gas tank ??'s

Discussion in 'The Garage' started by big_truxx, Dec 26, 2004.

  1. big_truxx

    big_truxx 1/2 ton status

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    i was told a while ago that in order to swap over to diesel you also need to swap in diesel tanks. is this true? i had always thought that a gallon of either or fuel being swapped into the other really wouldnt make a big difference as it'd be dilluted at a ratio of 1/20th of the tank.
     
  2. diesel4me

    diesel4me 1 ton status Premium Member

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    not absolutely nessasary

    I think you could use a gas tank for diesel--the only real difference in the 2 is the diesel tank has a different sending unit,it has a water sensor built into it,to light the "water in fuel" light when water accumulates in the tank,they also have a built in siphon hose setup to drain the water,both are nice to have,but not really nessasary in my opinion--if you use the truck often,and fill it frequently,and use a bottle of isopropanol dry gas ocaisionally,and drain your fuel filter once in a while,I doubt you'll have any trouble.....

    I dont know how much gas you can mix in with a GM diesel and have no ill effects--I do know one guy who filled a company truck with a 6.2 with gasoline,the truck had dual tanks and he used all but a half a tank of diesel on a long trip,and afraid he wouldnt be able to make it back or get diesel after dark,he stopped at the next station and topped off the tank with regular gas!!--he didnt remember he was driving the diesel company truck until he went to start it up and saw the glow plug light!!!!-:yikes: :yikes: :screwy: -he called the company,my brother is head of truck maintenence,he asked his boss if he wanted to send a wrecker to get him,or if he should drive the 100 miles each way to drain the tanks and refill it with diesel--his boss asked the owner of the company if they should go rescue him--he said "That truck is a POS anyway--I couldnt even get it started to plow my yard last year--tell him to dive it back---if he doesent make it,then send a ramp truck to get him"!!!---So he drove it over 100 miles with a roughly 50/50 mix of gas and diesel,and the guy at the gas station told him to add a quart of 2 cycle oil for good measure,it not only made it back with no problem,he said it actually ran better than it ever had on the previous trips he made in it--my brother simply topped off both tanks the next day,and that was over 2 years ago,and the truck still runs the same as ever!!.

    I had a VW Jetta diesel,VW claims you can use up to 3 gallons of gas per 14 gallon tank in the winter!!-:eek1: -many folks add a gallon or so to make them start easier in the winter(most of them are too cheap to fix the glowplugs,and dont like using starting fluid)--havent seen any meltdowns yet,but I cant see it doing a diesel any good running it on gasoline for any length of time--bet it would clean the injectors real good though...:crazy:
     
  3. big_truxx

    big_truxx 1/2 ton status

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    :saweet: sounds like good info there to me. i am thinking ahead on my work in progress. eventually i will swap something like a CAT 3116 I-6 or a 3208 V-8 into it. it already has dual tanks for the 454 so i figured that may as well use them. I did not think about the water sensors though. or the siphon hose. just things to consider when doing a swap for sure. and when this gets all swapped over how hard is it really to change the sending unit from a diesel tank to the gas? they are the same size I would assume as I know it costs more money to retool your machinces and make a different part for a gas tank... so gm most likely used the same tnaks w/ same sized holes but different sending units.
     
    Last edited: Dec 26, 2004
  4. k204dr

    k204dr 1/2 ton status

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    when did they have a water sensor in the fuel tank? my 84 and 87 diesels don't have anything like that in the tanks. just curious? I thought all they had was the sensor on the fuel filter.
     
  5. diesel4me

    diesel4me 1 ton status Premium Member

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    got me there

    My 82 K20 has it in the sending unit,and all the ones I've looked at in the junkyards did too,they were all about the same year (82-87?)--I have seen some with the sensor on the fuel filter instead though,but I didnt think to look at the sending units on those trucks--maybe some have 2 sensors,one at the filter and one at the tank????..:confused: ---anyway,mine lies to me,the "water in fuel" light comes on sometimes,and I drained the tank,and NO WATER came out!:mad: .
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I replaced my fuel tank about 3 years ago. The tank that went in was originally from a diesel K5. I checked the sender and stuff and compared it to the gas version. There was one extra do-ma-hickey on the diesel sender with a purple(?) wire. Removed the do-ma-hickey and cut the purple wire and it worked fine.

    A year later I swapped a 6.2 into my truck:doah:

    I just drained all the gasoline from the tank, flushed about half a gallon of diesel through the tank and lines then hooked it up. Never had a problem. Obviously I don't have a water in fuel sensor...but I do run a Racor fuel filter/water seperator.

    Rene
     

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