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  1. #1

    Default 4720 Engine Problem

    First of all, let me say that I have owned several pieces of JD equipment (6x4 Gator, F911, etc.) but never a utility tractor. about a year ago, I purchased a new tractor to replace my 30+ year old Ford 3000 which my father purchased new.

    I decided that this was a once in a lifetime tractor, so I went all out. I got a 4720 and equipped it quite nicely: confort guard cab (w/ ext. mirrors, work lights all around, horn....all the goodies), iMatch, 400cx loader (self-leveling) and a 4-in-1 bucket, pallet forks. Needless to say, I was envied....

    Last Sunday, I was driving my tractor to go get diesel (I was going to grade a parking lot of an organization that I belong to). When I left, I had 1/4 tank. I drove the tractor about 10 blocks, and saw the low fuel light come on. I was driving the tractor at about 3/4 throttle and was in C range. Well, I was close to the gas station at that time, and when I pulled in, the needle was darn near on empty.....I knew then that there was a problem.....

    I go out, and noticed that there was a trail of diesel behind me....something I knew was not good. As it turned out, there was diesel coming out of the overflow hose from the right side of the engine. I pulled the dipstick out, and diesel came flowing out of it as well....

    I called my father, and he came with his 1 ton truck and pulled me out of the way and to a nearby tire shop that my family member owns. We decided to pull the plug on the crankcase and see how much was in it turned out there was over 4 gallons of diesel/oil in the 2 gallon crankcase....and the filter was bone dry.

    The next day (1 week ago), my dealer came and picked up the tractor. After tearing the engine apart, they said that the tip of the injector had popped off, and had somehow fallen into the cylinder......and that allowed the diesel to freeflow into the engine. What noone can figure out is how the tractor ran essentially fine for several blocks.

    When I spoke to the service manager, he said they had contacted an engineer from Deere, and that they were advised that a new motor was being shipped from the factory....they didn't want to take any chances with the old one.

    The reason that I share all of this is that I am wondering if anyone has heard of this (or any other) problems with the Deere diesels in the 4x20 series tractors......or is mine just a fluke.

    I went to the dealer on Saturday to get a set of blades for my F911, and when I went back there, my new engine was already sitting there. I am not entirely sure how involved the engine swap is going to be, or if they have to remove the cab to do the work.

  2. #2
    Super Member Kyle_in_Tex's Avatar
    Join Date
    Oct 2002
    Giddings, Texas
    JD 4310,JD5420

    Default Re: 4720 Engine Problem

    Sounds like they are trying to take care of you. I don't think they have to pull the cab but not 100% sure. Keep us posted on outcome. I'm guessing here, but for 2+ gallons of fuel to leak past the rings would probably take hours. It probably had leaked the fuel past while sitting and you then ran it not knowing about the problem. This could have happened over the last few outings. Good thing a new engine is coming. Fuel is hard on bearings.

    Lets hope for a good ending.
    there are 2 kinds of oats. Oats in front of a horse, and oats behind the horse.

  3. #3

    Default Re: 4720 Engine Problem I had stated, we had pulled the crankcase plug and drained the contents and put fresh oil and a filter on the engine.

    The service manager said that they got the tractor fired, pulled it off and ran it long enough to take the loader off of it and pull it into a bay, that there was already diesel coming out the overflow and dipstick......

  4. #4

    Default Re: 4720 Engine Problem

    Well, it has been just short of 2 weeks now without my tractor. I just called the dealer, and the service manager said the new engine is in, but the radiator isn't back on the tractor. I also had them install a block/coolant heater while they had it there. This past winter I kept it in my heated shop most of the time.

  5. #5
    Gold Member
    Join Date
    Jun 2006
    South of Seattle
    Dad's=JD4440;IH1066;JD4020;JD3010;2 JD"B" 1949 & 1937(hand-crank)

    Default Re: 4720 Engine Problem

    I think there is an internal fuel leak somewhere between their high pressure fuel pump (plunger and barrel assembly) and their injection nozzles. Yes, they may have from a nozzle tip blew out and went into the cylinder, BUT I don't believe that ALL that fuel gets passed the rings while running and ends up in the oil pan/crankcase area. I have seen this failure (blown tip) on CAT engines and that extra "raw" fuel (unburnt) goes out the exhaust manifold ,then into the turbo, then in the exhaust pipe to the muffler. There is lots and lots of white smoke and banging sounds coming from the engines during this type of failure.
    I have looked at the 4720 fuel injection nozzle system under JD online Parts catalog, this is why I feel that excessive amount fuel in the oil pan came from an internal (under valve cover) fuel leak verses just a nozzle tip that came off in the combustion area(above the piston).
    Now, If it melted a hole thru an alumimun piston, then fuel could get directly to the oil pan going thru the nozzle tip. [Note: I have only seen that once in 25 years on CAT diesel engines. That engine was under a heavy load with lots heat and pressure in the cylinder when that tip blew and melt thru the piston.] Glad to see JD is going with a new engine for you.

  6. #6
    Veteran Member BTDT's Avatar
    Join Date
    Sep 2006
    North Texas
    IH M Farmall-propane powered, H Farmall (father-in-laws), Ford 1300 diesel

    Default Re: 4720 Engine Problem

    Where is the injector pump? We used to have some LeRoi air compressors with JD and Perkins engines, sometimes the seal on the injector pump shaft would go bad, and the fuel would go right to crankcase via the gear drive where it mounted to engine. You wouldn't know it was happening because it was still feeding the injectors, but internally in pump it was dumping fuel. Then like you say, you see fuel/oil coming out dipstick.
    Praise is not something you do to get closer to God, praise is a response to God being close to you.

  7. #7

    Default Re: 4720 Engine Problem

    I just stopped by the dealer....they were charging the ac, and all they had left to do is bolt the hood back on, attach the loader, and bring the tractor home.....they said they hoped to deliver it this afternoon!

  8. #8
    Silver Member
    Join Date
    Mar 2007

    Default Re: 4720 Engine Problem

    It sounds like they're really taking care of you! It can be frustrating the two weeks without a tractor, but on the other hand it is spring and it probably rained the whole time.
    Puget Island, Washington
    JD 4120

  9. #9

    Default Re: 4720 Engine Problem

    Update: After calling the dealer yesterday just after lunch (they had told me that they should have it back to me on Tuesday afternoon after I stopped there in the morning), they admitted that they forgot to deliver it back (there were a few excuses thrown in there, but the point was they dropped the ball). I just go the tractor back yesterday (Friday) at 4:00. They did fill the tractor back up with diesel and gave me a couple new Deere hats though.....

    Now I need to find some time when it isn't raining (so I don't tear up the grass) and get some things done!
    JD 4720, Comfort Guard Cab, 400cx Loader, 4-in-1 bucket, iMatch

  10. #10
    Elite Member
    Join Date
    Jul 2006
    JD 4520, Toolcat 5610, Bobcat S300, Case-IH 125 Pro, Case-IH 245, IH 1086, IH 806

    Default Re: 4720 Engine Problem

    What was the problem that caused the fuel in the crankcase?

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