Cummins Marine Diesel Repower Specialists Forums Cummins Marine Engines Very High Oil Consumption on QSB 5.9

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    Topic
  • #25396

    tod
    Participant

    Hi All – I am moving this topic here from boatdiesel.com because of minimal response there –

    I have very high oil consumption on one of my two engines on a 2005 Tiara Open cruiser. Here are some of the details:

    – Both engines have appx 980 hours.

    – Starboard engine uses appx 1 quart per 1,000 gallons of fuel.

    – Port engine uses appx 40 quarts per 1,000 gallons of fuel.

    – The high oil consumption has probably been going on quite a while but has been masked because we had been going on very short trips (in the Canadian Northeast) and because consumption is lower at idle than cruise. This summer we have done some high speed cruising in the Northwest.

    – I calibrated the dipstick and am running 15 quarts of Rotella 15-40 in the pan. I tried running with only 12-13 quarts but did not observe any change in the high oil consumption.

    – Little to no oil under engine

    – Consumption seems significantly higher at cruise than when traveling slowly.

    – A very small amount of oil evidence around the back of the engine on Air Sep stuff and gear cooler area.

    – No smoke from engine during operation except for a small “puff” when power is applied after a long time idling.

    – A small number of oil droplets are visible on the water when the engine isn’t “hot” and is run up to 2000 rpm in neutral.

    – A small amount of blue smoke visible in the exhaust when the engine is run up to 2000 rpm in neutral after running at cruise conditions (i.e. the engine is “hot”).

    – Possible causes identified by a Cummin´s tech (quick visit in Canada this summer) included a failed turbo oil bearing seal and valve stem seal failure(s).

    I have removed the in/out on the turbo and both are clean.

    The Cummins tech in Canada did a qualitative blowby test by removing the valve cover hose going to the AirSep system and putting his hand over each He said they were both similar but it was a pretty quick and dirty test.

    I know I probably need to get a mechanic involved (Cummins or other) but would really appreciate thoughts from the experts before I start down that path.

Viewing 7 replies - 1 through 7 (of 7 total)
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  • #25508

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    All is good!

    #25485

    tod
    Participant

    Stand down

    I am on travel for a couple of months starting on December 4th. I’ll try and get this information gathered before that time but it is somewhat unlikely.

    I’ll repost when I get this info but until then I guess you all should stand down on this issue.

    Thanks, Tod

    #25475

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    To do this right, you need to do 3 things at this time..

    1) I want to see the engine (all of it) including the air intake system, exhaust system and oil drain line from the turbo to the engine

    2) Let’s see the air side of the after cooler as removed from the aftercooler.. No cleaning allowed.. That’s going to tell us where this oil may be coming from

    3) A Properly done blow by test.. I’d do that last as 980 hours does not equal a blow-by issue unless you had a piss poor install that allows lots of things to take out an engine that way early on..

    Tony

    #25436

    tod
    Participant

    Math is Right

    I burn about 12 gallons/hour of fuel at cruise and consume a quart of oil every couple of hours at cruise.

    The local Cummin$ folks want to do a sea trial and measure blowby. A local mechanic (not factory) wants to do a similar thing but his blowby test is to undo the oil filler cap and put his calibrated hand over it.

    I suspect that major surgery will be recommended after this. I would like to be armed with the thoughts of the experts on this forum regarding credible scenarios before I start down that path.

    Thanks to all, Tod.

    #25419

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    40 QUARTS per 1000 gallons of fuel ????? That would be 1 qt per 25 hrs or maybe 1 qt per 25 gallons of fuel??? Is my math right?

    Are you sure???

    Tony

    #25410

    tod
    Participant

    High Oil consumption – Additional Information on

    As suggested by Jason Leslie (thanks), here is some additional information:
    1 – CPL is 8464
    2 – S/N is 46365672 (port engine)
    3 – History of Use – I bought the boat in Connecticut in Fall of 2015 with 450 hours on both engines. Used for offshore fishing and some cruising before I bought it. I cruised it over to Green Bay Wi through Canada and the Great Lakes. I trucked the boat to Seattle in Fall of 2016. I had both gears replaced in fall of 2016 because the starboard engine had “black” oil. I replaced both gears because of the difficulty in getting set up to do the gear replacement (pull genie etc. Long story) was so difficult and I got some help on the price from the ZF rep.
    4 – RPM at WOT before and after the problem was 3050 (controlled electronically). The boat comes right up to WOT when loaded with gear and fuel.
    5 – I went through the raw water system in fall of 2016. I replaced the aftercooler on the subject engine (sbmar OEM) because the core was ugly however it didn’t leak.
    6 – Photos of the installation – I have attached a photo showing the engine area with the hatch open and a mechanic between the two engines. This is a standard Tiara installation. I can take more photos if that will help but this is what I have right now.

    #25399

    Jason Leslie
    Participant
    Vessel Name: PierFection
    Engines: Detroit 6V92TA
    Location: Channel Islands, California
    Country: U.S.A.

    Homework before advice.

    I see a future in photography and historian for you. If you look at about 99% of the posts on this site where people are looking for assistance, you will see the same response, “CLEAR IN FOCUS PICTURES OF THE ENTIRE ENGINE INSTALLED FROM ALL ANGLES AS IF I WAS THERE, CPL NUMBERS AND SERIAL NUMBERS, HISTORY OF USE, WHAT IS YOUR RPM WOT IN GEAR FULLY LOADED NOW AND BEFORE PROBLEM, WHEN WERE YOUR AFTERCOOLERS TAKEN OFF AND SERVICED PER PROTOCOL?).

    I’m just trying to save Tony some time.

Viewing 7 replies - 1 through 7 (of 7 total)

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