What’s The Best Way To Clean Dirty Engine Oil?

Discussion in 'General Maintenance/Repair Questions' started by Alex F, Dec 13, 2007.

  1. Alex F

    Alex F Well-Known Member

    Nov 14, 2006
    East Coast
    2005 420DB with AB 11 DLX Tender, Raymarine Dual E120 MFD/Radar/XMWeather, ST7001 A/P, AIS, SeaLift
    T-Cummins 450Cs Straight-Drives, 9KW Onan Generator, 40HP Yamaha for tender.
    During the first introduction to our 320DA I’ve checked the engines oil and noticed that it’s was dirty (black), but the it didn’t feel like it lost it’s quality, just the color. I’ve seeing oil in this condition few times in cars and simply changing the oil with filter fixes most of the discoloration. So, when we purchased the boat I’ve changed the oil and installed performance (larger) filters. After that I ran the engines for about 10 minutes and when I checked the oil I was very surprised to see that the color didn’t become any lighter. So, I got few question:

    • What would make the oil get so dark other than not changing it on time?
    • What would be the best way to restore the clean color? I’m thinking that it would take about 3 (2 to flush and 1 final) additional oil changes, which is about 11 4gal. bottles to do both engines. Would anyone any other than Quicksilver SAE 25W-40 (based on the manual this is recommended oil) just for flushing it or should I just eat the cost of over $200?
    • Would I have to change the filter again, or by flushing it with new oil will keep the filter clean?

    So far, my plan is to drain current oil (leaving new performance filter unchanged with the assumption that it’ll get cleaned with every fresh oil I put in), refill and run the engines for 5-10 min. Then repeat the same steps until the oil is clean (hopefully, no more than 3 times). Does it sound like proper way of handling this?

    P.S.
    When I checked generator the oil was a little dirty as well, but as soon as I changed the oil with filter and ran the genny for 10 min. the color of the new oil remained crystal clear.

    Thanks,
    Alex.
     
  2. ghuskin

    ghuskin New Member

    Jul 10, 2007
    Lake St. Clair, DYC
    SRV225 Cuddy Cabin, 1983
    228 Mercruiser w/ pre-Alpha1 "R" Drive
    Alex,

    I'm not a chemist, and do not pretend to be an expert on engine oil, so I won't even try to explain. I can only give my understanding as I see it.

    1) after changing oil, there is always residual in the block, heads, oilpan, etc., that sticks to internal engine parts, and collects in little gulleys.

    2) after draining (as much as you can), replacing with new oil and filter, the viscosity and cleaning properies (if any) in the oil are what you are after, not the color.

    There should be no reason to process that much oil through an engine just for the sake of "color".

    When you take your car to "Jiffy Lube", they don't run excess oil through you automible engine until they achieve the desired "color". the same would apply, I think, to your marine engine.

    Gregg
     
  3. Dave S

    Dave S Well-Known Member TECHNICAL Contributor

    Oct 3, 2006
    Upstate South Carolina
    Boatless
    Boatless
    Were you able to get all the old oil out of the crankcase? Many times if you are sucking oil out via the dipstick tube it is not possible to get it all removed. Then that (dirty) oil mixes with the new stuff. On my 350 MAG there is always roughly one quart that I can't get out since it only takes 4 quarts to refill the cranckcase.
     
  4. Alex F

    Alex F Well-Known Member

    Nov 14, 2006
    East Coast
    2005 420DB with AB 11 DLX Tender, Raymarine Dual E120 MFD/Radar/XMWeather, ST7001 A/P, AIS, SeaLift
    T-Cummins 450Cs Straight-Drives, 9KW Onan Generator, 40HP Yamaha for tender.
    Gregg,
    I 100% agree that the viscosity and cleaning properties is the goal. However, with any oil change you would expect the oil to be somewhat clearer, considering the fact that it's hard to get it all out via tube. But, in my case it looked like I didn't changed the oil.

    Dave,
    When I bought this boat I had an opportunity to talk to very experience mechanic who advised me with a different method doing an oil change. He suggested not running the engine to warm up the oil prior changing it (as most people do, including myself in the past), but instead let it sit for a while and drain to the oil pen. The pump is strong enough to get that cold oil out. His explanation was that when you run the engine all the acids that was at the bottom is now around the whole engine and it’ll take few hours for everything to get back on the bottom. In the mean time one is proceeding extracting the oil via tube and this takes minutes not hours. So, two things take place, 1-bad acids are lifted and distributed back to the engine components, 2-more of old oil is left and not being able to extract (may be just 4 qrts). Therefore, only 4 quarts of new oil can be added.

    So, I had the oil sitting for two weeks, due to boat transporting delays. I think when I had extract it there was much more than 4 qrts, almost 5. I added 5qrts to get the mark on full. I think in my case the old oil was just too dirty and as soon as whatever was left mixed with new oil it absorbed the same black color.

    May be I’m being too picky and over estimate the number of oil changes. It could be that with next oil change I’ll see the immediate effect. Also, one of my friends told me that I could try using the plug at the bottom and drain the oil like we do in cars instead of using the tube with pump. I’m not sure though if the plug is there on every marine engine and if I have the room to put a container to hold the draining oil.

    Thanks,
    Alex.
     
  5. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    Don't sweat the color. My 400 hour 8.1 Crusaders make dirty colored oil in no time. For some reason, the genny does not. It's the hours not the color that are important. Unless your engine has a long history of no oil changes, there is nothing to gain from trying to make its oil pristine looking. The look won't last.
     
  6. Weave

    Weave New Member

    Jun 1, 2007
    Western, MA
    200 Sundeck 2005
    4.3 MPI Alpha I Gen II
    Just a side note....Would carbon build up cause dirty oil? Not saying its the sole cause just curious is all
     
  7. Alex F

    Alex F Well-Known Member

    Nov 14, 2006
    East Coast
    2005 420DB with AB 11 DLX Tender, Raymarine Dual E120 MFD/Radar/XMWeather, ST7001 A/P, AIS, SeaLift
    T-Cummins 450Cs Straight-Drives, 9KW Onan Generator, 40HP Yamaha for tender.
    My engines have only 268 hours on them and the last 100 hr. service was done at 200 hours. This would make the oil be used for 68 hours.

    On my 240 the color change is normal from light brown to darker brown. But on 320 it just like black. I understand what you're saying, but I just expect it to be a little lighter than black.
     
  8. ghuskin

    ghuskin New Member

    Jul 10, 2007
    Lake St. Clair, DYC
    SRV225 Cuddy Cabin, 1983
    228 Mercruiser w/ pre-Alpha1 "R" Drive
    Would operating conditions dictate the break down of the oil? Like in an auto/truck, you change the oil more frequently if towing a trailer, lots of city driving, etc. vs. highway?

    I them could imagine lots of time spent under planing speeds & WOT operation would break down oil faster vs. cruising speed?

    Just a thought.
     
  9. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    As long as you use a high quality oil ( Rotella T is suggested by Crusader for 8.1s ) that has the properties required for demanding conditions such as boating, and you change the oil and filters at the recommended intervals, you will be fine. For some reason, my 8.1s have always made dirty oil. The compression is good and they burn no oil. After an oil change, it's back to black within 15-20 hours. The only thing I would add is the importance of not overloading the engines. I see lots of posts where people talk about running at 3800-4000 RPMs. This is seldom good for an engine unless it is part of a break in schedule. Make sure the engine turns at the high end of the spec'd WOT and then cruise at no more than 75-80% of that number. Properly maintained, a gas engine will run a few thousand hours without breaking if it is not overloaded.
     
  10. Nehalennia

    Nehalennia Well-Known Member

    Aug 22, 2007
    Marysville, WA
    2001 310DA twin 350 MAGs, Westerbeke 4.5KW
    Twin 350 MAG V-drives
    Alex,
    It may be that at some point either during the 100 service or prior to that someone put a Oil flush product in there, to show a "shiny-clean" oil and backfired. What that may have done is busted free all of the carbon. This isn't that good of news because if that's the case some or a lot of that carbon can get into the bearings, rings or elsewhere(which may cause damage). It may explain why your oil has returned to dark/black nearly immediately.
    My advice is that you just change oil at more frequent intervals and hopefully the oil itself is eventually clean out the grime. Your Performance filter may be overkill if you intend to change more frequently but it should hurt. I like to run with a clean engine as well and change oil every 30 hours. By pumping out of the dipstick I yeild just under 5 quarts.
    If you decide to do several changes at one time, you should run the engines at minimum of 30 minutes before pumping or draining out.
    Best of luck
     
  11. Alex F

    Alex F Well-Known Member

    Nov 14, 2006
    East Coast
    2005 420DB with AB 11 DLX Tender, Raymarine Dual E120 MFD/Radar/XMWeather, ST7001 A/P, AIS, SeaLift
    T-Cummins 450Cs Straight-Drives, 9KW Onan Generator, 40HP Yamaha for tender.
    sbw1,
    From what I understand 3800 is the cruising range for 320. From couple of rides I got on mine I felt like if I lower under 3400 it starts get off plane.

    Alex.
     
  12. Alex F

    Alex F Well-Known Member

    Nov 14, 2006
    East Coast
    2005 420DB with AB 11 DLX Tender, Raymarine Dual E120 MFD/Radar/XMWeather, ST7001 A/P, AIS, SeaLift
    T-Cummins 450Cs Straight-Drives, 9KW Onan Generator, 40HP Yamaha for tender.
    Nehalennia,
    Thanks for suggetions. Do you think even with the flushing and 30 min running engines I still need to change the filters?
     
  13. Nehalennia

    Nehalennia Well-Known Member

    Aug 22, 2007
    Marysville, WA
    2001 310DA twin 350 MAGs, Westerbeke 4.5KW
    Twin 350 MAG V-drives
    Definitely. That's what is filtering the carbon out.
     
  14. jg300da

    jg300da New Member

    Oct 9, 2006
    None
    Your
    Business
    I'm with Todd on this. During a normal 60-70 hour season I'll use the pump thru-the-dipstic method about halfway through the season, then the remote drain tube method at seasons end when the boat comes out of the water. Use a fresh filter both times. Any more frequency than that is in my opinion wasteful.
     
  15. Nehalennia

    Nehalennia Well-Known Member

    Aug 22, 2007
    Marysville, WA
    2001 310DA twin 350 MAGs, Westerbeke 4.5KW
    Twin 350 MAG V-drives
    I'm adding the tube out of the bottom oil pan to my engine before they re-install it later today. Since I will be trailering it will be easy to change oil frequently.
     
  16. Alex F

    Alex F Well-Known Member

    Nov 14, 2006
    East Coast
    2005 420DB with AB 11 DLX Tender, Raymarine Dual E120 MFD/Radar/XMWeather, ST7001 A/P, AIS, SeaLift
    T-Cummins 450Cs Straight-Drives, 9KW Onan Generator, 40HP Yamaha for tender.
    In that case I think it's better to change the strategy a little. I'll put few hours on the current oil I just replaced, so I get to use it a little and work it in more. If there's no short cut in this, then might as well get to use some of it.
     
  17. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature

    There are really two issues. One is how the hull goes through the water and the other is what power settings are required to get a good ride. When the engine and the hull are properly matched, you get a good ride without overloading the engine. Your 350s have a spec'd wot of 4600-5000 rpms. Some companies look at the top number as a never excede number and shoot for the middle of the range. Crusader recommends this approach to propping. So....using that logic your ideal wot target is 4800 rpms. 75% of that is 3600 and 80% is 3840. Your number of 3800 is at the top end of the ideal range and you should easily get 2000 hours from those engines with proper maintenance. You might increase engine life by 33-50% by cruising at 3600 max. A knowledgable friend told me many years ago that 350s would never wear out if run at no more than 3000 rpms. I put that advice to the test with a 1979 26 foot SR Express. It had close to 4000 hours on it when I sold and it was still running strong and used no oil. A friend bought my 1986 30 foot WEr and did not have any problems with those 350s until they had about 2600 hours on them. He ran the boat much harder than I did and cruised it at 3500+. Still, with a valve job it went several hundred more hours before he sold it. Loading is as important as oil changes and many inexperienced boaters fail to understand that while being obsessive about oil changes. You need to do both.
     
  18. Alex F

    Alex F Well-Known Member

    Nov 14, 2006
    East Coast
    2005 420DB with AB 11 DLX Tender, Raymarine Dual E120 MFD/Radar/XMWeather, ST7001 A/P, AIS, SeaLift
    T-Cummins 450Cs Straight-Drives, 9KW Onan Generator, 40HP Yamaha for tender.
    sbw1,
    Many thanks for the advise. I'll be sure to keep it in mind. As you can see I've moved up from smaller boats and speed was something I liked. But, I got to the point that I'd like to enjoy the actual cruising on a larger boat instead of getting from point A to point B. In case with my 320, the key question is if the optimum numbers point to slightly higher RPMs. Based on statistic posted by other members:

    "averaged .9 mpg at 26 mph/3600 RPM (350 MAG V-drives)"

    Boat test has the following results:
    Top Speed: 35.4mph
    Cruise Speed: 24.8mph
    Cruise Range: 170miles
    Time to plane: 5.1sec.
    0 to 30mph: 16.8sec.

    Looks like I may manage to be in the range of 3200-3400 RPMs to hold the suggested cruising speed and hopefully keep the fuel burn at optimum level. 24-25MPH sounds to me like comfortable cruising speed.

    By going with your suggestion to keep it close to or under 3000RPMs I'll have to play with it next season and see how the boat performs.

    Thanks,
    Alex.
     
  19. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    You do need to experiment to find out what works for you. I suspect that you will experience reduced performance close to or under 3000. You may find 32-3400 works well but the deep v hulls SR uses for good sea keeping trade off effeciency for a better ride. (still 1 mile per gallon is empressive.) You should also check your wot once a month to make sure that number has not gone down. Gear and bottom dirt degrade wot. You need to compute 75-80% of any new lower wot numbers to avoid damaging the engines through overloading. Generally a boat that gets used a lot will hold its wot number all season. I've notice virtually no change in my numbers and this is on a boat that gets launched on April 15 and gets pulled on October 15. We keep our clothes and supplies on the boat all season so that gear weight does not change. And the bottom stays fresh through the use of a good ablative paint. Fuel, waste and water account for most of the weight variation. At 3000 rpms I lose mpg. At 3200 the hull lifts higher out of the water and mpg improves. My ideal cruise is about 3500.
     
  20. top*prop

    top*prop Member

    68
    Jun 28, 2005
    my own little world
    boatless
    boatless


    i agree, this is one of my biggest complaints after changing a customers oil. have had several this year that swear we didnt change it becasue it is as black as when they brought it in. very hard argument to win.
     

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