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Oil change with full flush?

Discussion in 'Engines' started by TahoeJohn, Nov 1, 2020.

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  1. TahoeJohn

    TahoeJohn Member

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    I'm looking through the receipts that I inherited with our new-to-us boat and found this service from last year, performed by N&G in Hollywood, FL:
    temp.png

    Is there a legitimate reason to do a complete flush (i.e. drain, fill, run the engine, drain, fill)? I suppose you would get a more complete oil change out of it, but it seems like a lot of extra work. $3521 for the two mains (Cat 3412Es) and two Onan generators, so the total cost isn't that outrageous.
  2. TahoeJohn

    TahoeJohn Member

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    (Sorry for the too-large picture -- I'm trying to figure out how to fix it but can't seem to find an "edit post" button...)
  3. NYCAP123

    NYCAP123 Senior Member

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    Possibly the previous oil analysis showed contaminants?
  4. Beau

    Beau Senior Member

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    I've done that type of flush when I've done engine work, like valves and head work. to make sure all the "dropped" debris is removed, But its unusual IMO for a regular oil change.
  5. TahoeJohn

    TahoeJohn Member

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    Good idea. I just checked on this and the previous samples (from 2017) from each engine show all green.
  6. TahoeJohn

    TahoeJohn Member

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    The other work done that same visit was to drain the coolant (from only the port engine) and replace a leaking raw water cooling pump. Perhaps they were concerned about that, somehow. In any case, it's good to know that this isn't the "norm". Thanks!
  7. Capt J

    Capt J Senior Member

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    N+G engineering is an excellent Cat repair shop. If you call them, speak to Gabriel and he'll remember the boat and tell you why. I could see doing a flush IF somehow water got into the oil (aftercoolers leaking etc.), after major work, or if there's bad oil samples. The total cost is very reasonable.
  8. Brian G

    Brian G Member

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    I have a related question. It's that time of year again and I'm about to change the oil in my 3412e's as well. I've used Rotella T4 in the past but wanted to see if anyone would recommend either a different brand or a different Shell product such as the synthetic options. I put 425 hours on the engines this past year. Thanks.
  9. Capt J

    Capt J Senior Member

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    Yes, CAT 15w-40 DEO is what I use in CAT's.......Mobil would be my second choice. Rotella isn't what it used to be. That's a lot of hours in a season.
  10. Slimshady

    Slimshady Member

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    J what are your concerns with Rotella? We use it in most all our diesels motors( over 15). We use synthetic blend at 250hrs religiously. Just bought $500 more this morning
  11. NYCAP123

    NYCAP123 Senior Member

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    It's so good to hear of a boat getting used, however that's way too many hours to go without changing your oil. Most places recommend changing the oil each season, but that's because most boaters only put on way less than 200 hours. Check your manual for recommended intervals. If it says seasonally consider that 200 hours. Nothing wrong with Rotella. It's been the standard for a long time. Others have just gotten better. If you switch to synthetic that would be a reason to flush the motor as you'll want to get the old oil out. They don't blend.
  12. Brian G

    Brian G Member

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    Thanks for the feedback, Capt J and NYCAP123. Rookie mistake on not changing the oil sooner. It won't happen again!
  13. motoryachtlover

    motoryachtlover Senior Member

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    Brian G, part of what I do involves heavy equipment and for whatever reasons manufacturer’s are moving to extended oil change intervals. Some manufacturers are saying you can sample the oil and if all is well keep running. If you have an engine person that you have confidence in run it by him/her and see what they think. Let’s see what the rest of the forum thinks about the sample routine. I am sure I will get some pushback on this but I change my oil in my personal vehicles every 5000 miles. I think the 3000 miles is a bit much.
  14. Brian G

    Brian G Member

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    Thanks for the suggestion, motoryachtlover. Your post reminded me that I need to do a sample oil analysis for both engines and the genset. After doing a simple internet search, I came up with Blackstone Labs. Does anyone else have any other suggestion?

    Thanks in advance.
  15. Pascal

    Pascal Senior Member

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    The reason oil change intervals in cars have been extended to 5000 miles and more in many cases is that tolerances on new car engines are much tighter than they used to be years ago along the fact that the electronic management allow for more efficient running engines

    I m not sure the progress in diesel technology has been has big except maybe in the last few years.

    400+ hours without an oil change is pushing it I think

    I really can’t think of a reason to do an oil flush unless something happened like water ingestion. Even a minor amount of coolant or raw water getting in the oil during maintenance should not be enough to do a flush.
  16. NYCAP123

    NYCAP123 Senior Member

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    When I got a new car in 2016 the 2nd oil change was scheduled for 10,000 miles and then every 5,000 after that due to synthetic oil being changed. However with regular oil I'd stick with 3,000 although the recommendation is now for 5,000. I suspect the 5,000 recommendation for regular oils has more to do with the government and energy independence than changes in oil.
  17. mapism

    mapism Senior Member

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    Cat DEO is just Mobil Delvac MX with a yellow label.
  18. mapism

    mapism Senior Member

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    Unusual on pleasure boats maybe, but I wouldn't be concerned at all, considering also the one year timeframe.
    On any commercial boat, oil changes at less than 500 hours are unheard of.
    And for instance, off the top of my head 600 is the manufacturer recommendation for all FPT engines.
    Some of which are nowaydays also rebranded as Cat.
  19. Capt J

    Capt J Senior Member

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    Yes CAT. Go to your local dealer and buy an S.O.S. oil sample kit, it's around $30 and comes with the sample bottle, shipping bottle, tubing, pre-paid shipping label etc. (make sure to fill out the label prior to attaching it to the sample bottle). They also sell a hand pump that the bottle screws on, also around $30. Start the motors and let them run 10 minutes, then pull the sample from each motor. I cut the sample tubing about 3" longer than the dipstick for each motor. Then just stick the bottle in the mail and you'll get e-mailed results within a couple of days.
    Last edited: Nov 2, 2020
  20. Capt J

    Capt J Senior Member

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    Mobil is also the oil of choice of Cummins, MAN and other Marine diesel manufacturers.

    A large DD/MTU dealer told me they've been seeing a lot more ring wear on engines running Rotella over other brands. I've personally noticed that it tends to lose 10 PSI of oil pressure after 50-100 hours on it on various motors. I stick with the manufacturers oil generally, or if not, use Mobil.......

    All of the yachts I manage, the oil gets changed annually because none of my customers put those kind of hours on their yachts. I just had a set of MAN 1200's synthetic oil changed and it has 70 hours on the oil (and a year).

    NYCAP- the additive packages on modern oils are acres ahead of what was 10 years or so ago and the newer engines burn much cleaner, both causing the extended mileage intervals. My expedition oil change light comes on around 7500 miles (or 1 year) and the oil looks pretty darn clean at that time if you put it on a white paper towel. You generally change oil because it is contaminated with hydrocarbons (unburnt fuel) and wear metals, not because the oil itself is bad.