Inspecting John Deere 6068 Accessory Drive Belt and Bearings

An important annual service check on a diesel engine is to check the drive belt and bearing condition on all engine-driven accessories including the alternator and coolant pump. The video below steps through this simple service check on our John Deere 6068AFM75. The engine is a 266 hp, M2-rated marine diesel that is just over 10 years old and is approaching 11,000 hours of service.



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11 comments on “Inspecting John Deere 6068 Accessory Drive Belt and Bearings
  1. Bjørn Alexander Nitter says:


    Thank you for your informative video. I am installing an Balmar 97 EHD as a secundary alternator and trying to figure out what type of serpentin pulley to mount. We have tree options; 1 A solid alternator pulley, 2; a One Way Clutch pulley (OWC) and 3; a Overrunning Alternator Decoupler pulley (OAD). Do you know the type and brand of the pulley mounted on your Balmar alternator ?

    Kind regards

    • We were using a simple solid alternator pulley. I can’t think of a reason why you would want or need a one way clutch or an overrunning alternator decoupler pulley. Ours was just a simple serpentine belt pulley likely installed by Balmar on supply to Cascade Machinery (Deere Distributor) who did the alternator install and final configuration prior to shipping to Nordhavn.

  2. Christine McClintic says:

    Hello James and Jennifer!

    You may recall that I wrote an article about your vessel and John Deere engine in 2010 for the John Deere Marine PowerSource magazine. I’m so happy that you are still cruising with your 6068AFM75. Is it still running well for you?

    • Great hearing from you. Yes, the 6068AFM75 is running like a champ with 11,073 hours. It’s been around the world and, in all this use, it’s only had new fuel injectors at 8,000 hours, a drive belt idler bearing, and consumables. Same water pump, alternators, turbo, etc. It have never failed to start and has never caused us to need to redirect or change plans for service. It’s a winner. Thanks for checking in.

      • Christine McClintic says:

        That’s wonderful to hear, James! John Deere Power Systems would love to share your story (again). We would like to learn more about your and Jennifer’s passion for adventure and traveling aboard your boat. I know that you’re off the coast of Scotland, but would you be available for a phone interview? Or, perhaps I could send you some questions for you and Jennifer to answer at your leisure? Let me know your thoughts.

  3. Jack Apple says:

    James, I love your helpful videos like everyone else!
    I think I noticed a screw/bold on the back of the alt that looked like it was loose at 22:26.

    • Good eye. I agree it does look like that machine screw is loose but it’s actually just a screw with integral washer where the lock washer underneath the integral washer is smaller than the washer and makes it look like the machine screw is not pulled up tight.

  4. Mike Ukena says:

    Directly below the tensioner, there appears to be a water hose with a missing clamp. Am I seeing it correctly? Or is it just out of view?
    Also, what a dream changing a serpentine belt on that engine compared to a car with a tight fitting V8!

    • Your right about the maintenance access on this engine being a dream compared to some cars. It’s pretty nice. There are some jobs that are still difficult but, generally, we have good access. On your question on the unclamped hose, it’s probably just behind something in the video. There is a 2″ cross over pipe visible at that location and a heater hose and both are properly clamped. Thanks for asking about it though.

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