Preview: Marine Diesel Engines, Part 3 – Changing the Impeller

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The rubber impeller in the raw water pump pushes water through the cooling system.  Learn how to inspect this critical part and how to change an impeller if necessary.

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30 Responses So Far to “Marine Diesel Engines, Part 3 – Changing the Impeller

  • Avatar

    David Green says:

    This website is worth EVERY SINGLE PENNY of the monthly fee. I’m getting back into sailing after 40+ years away from it and the amount of information and the level of quality of the material is just fabulous. Thank you so much!

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    George Lippitt says:

    Thanks for the videos. They helped me learn about my engine and i have referred others to OCH. Can you do a video on changing out the seawater pump.

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    Terry Billard says:

    I have learnt more watching these first 3 videos than I did when I took a Engine Maintenance with the Canadian Sail and Squadron course …. and at cost 1/4 the price of the course .. Great videos…..Thanks.

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    Andre Beneteau says:

    Great video….I’m not sure if we are allowed to talk about products on here but I use the Speedseal product and my impellers last twice as long and are 5x faster to change out. Great product and I have no shares in the company….lol.

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    Ben Zehnder says:

    Thanks for a great series. I am a first time diesel marine engine owner and the information is very well presented.

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    John Thompson says:

    These videos on Diesel engine systems are great. I would love a series on changing the primary and secondary fuel filters, and bleeding the fuel system.

    Thanks
    John T

    • Steve Stone

      Steve Stone says:

      That’s on the way John. Please stand by, we have a couple other videos we want to get out first. Steve

      • Avatar

        Steve Bryant says:

        Your videos are excellent and nicely done, thank you. Looking forward to the bleeding video and hope that you will use the Yanmar engine too. I’ve been aware of your site and have enjoyed limited access in the past. Now, in time for Christmas, I have joined and am looking forward to wearing my Off Center Harbor.com hat on Christmas morning!
        Thank you again,
        Steve

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    Cheryl Strohmeier says:

    Great videos on diesel engine maintenance. Thank you for making it so easy to understand and apply. I had an overheating problem early this season after changing out the raw water impeller before launching. Thinking that it could not be the raw water impeller I went ahead and checked the fresh water impeller and found that with a broken vane. Replaced it and the anti freeze and still had the overheat problem. Then I changed both thermostats figuring that must be the problem. Still had the problem. Then I checked the new raw water impeller I had just replaced a few weeks prior and found that had broken vanes also. Well, I changed that out and she’s run fine since. Although it took a while and some brain storming from fellow sailors, I felt a great sense of achievement to fix it myself! I’m really looking forward to more of your videos Jon.

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      Jon Bardo says:

      Cheryl,
      Is your engine a Volvo? If so, be very aware of a problem with engine coolant rubber water pump impellers, I have seen them disintegrate prematurely and ruin the engine. The vanes get caught in the cylinder head coolant passages and the engine overheats, not good.

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        Captain Nemo says:

        Is this because the ethylene glycol (collant) is not compatible with the rubber, or is it another issue, and has Volvo fixed the problem in the two years since this comment was posted?
        Thanks
        Greg

  • Steve Stone

    Steve Stone says:

    Lovin’ the uproar for more diesel videos. This series is just beginning. Still to come is the fuel system etc. Jon will take us through pretty much everything you can see on this engine. Hang on, we’re editing as fast as we can, and trying to keep a variety coming out too. Thanks!

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    Allen Dodge says:

    Sil Glyde from AGS corp. is the o-ring and rubber lubricant we use in our shop. (diesel and heavy equip.) Available at most auto parts stores. Silicone based, compatible with almost all rubber, works great in a wide variety of applications.

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    Robert Green says:

    Be careful that the lubricant on the impeller tips is not incompatible with the rubber of the impeller. Some lubricants will decompose the rubber.

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    Daniel Culpepper says:

    Yes! Bring on the systems videos. Loved the Electrical series and am enjoying this as well. Experts plainly explaining. Thanks!

    • Avatar

      Jon Bardo says:

      I also very much enjoyed the elec videos and plan on enhancing my Diesel Class with a few added tips from Don.

  • Larry Venezia

    Larry Venezia says:

    Another great how to video for the do it yourselfer, whether a wooden boat or a boat of any material. Videos like these more than make membership to OCH a good investment. Thanks.

  • Avatar

    Steph Smith says:

    This is for me what OCH is best at, making experts available and being asked the right questions, to help me be a more knowledgeable boater. That discounts the inspirational work that you guys do to get me beyond non boating work. I am extremely satisfied with my OCH membership. BRAVO keep up the good work!

  • Avatar

    Gino Del guercio says:

    These videos are very good. Let’s see more like these. The videos about wooden boats are nice, but I have a modern boat. Practical videos on how to repair and maintain modern glass boats will keep me coming back.

  • David Tew

    David Tew says:

    Might it help to put the gasket in warm water (to keep it from shrinking) while replacing the impeller?

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      Jon Bardo says:

      Yes, I guess you could soak the gasket in water to help slow the shrinking problem. However, the instructor always tries to present possible problems that can happen when attacking a repair in hopes that the student will foresee the need for spare parts ( in other words, one should always have a spare gasket to go with your spare impeller)! Plus a tube of silicone, just in case. ThankYou for your comment.

  • David Tew

    David Tew says:

    Good tips. I have to do this before winter. Does he have any suggestion about a particular grease to use (or not use) on the vanes when installing the impeller? Thanks.

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      Jon Bardo says:

      Most any grease, I like to use synthetic grease (sparingly of course) , this also gives the impeller a little lubrication until the water arrives!

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      David Gruendel says:

      On the recommendation of a fairly knowledgeable dockmate, I used liquid soap the last time I changed my impeller. I didn’t have any grease, and it’s been my understanding that once the motor starts running, the impeller is lubricated by the water it’s pumping. In other words, grease or soap, the purpose isn’t long term lubrication, just ease of installation. Am I correct?

      • Avatar

        Jon Bardo says:

        David,
        Yes you are absolutely correct, the grease or soap quickly washes away, it’s use is for ease of installation. Note, Most impellers are made from neoprene rubber which is not disturbed by grease or engine oil.

        JCB

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