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Thread: 15W-50 instead of 10W-40?

  1. #1
    Registered User bluegrasspicker's Avatar
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    15W-50 instead of 10W-40?

    OIL THREAD!

    Will the sun fall from the sky if I use 15W-50 in my K1600GTL? I have couple gallons left from my RT.
    Last edited by BluegrassPicker; 06-29-2012 at 02:36 PM.
    Tom Barrie
    http://bluegrasspicker.blogspot.com/
    2012 K1600GTL
    2002 R1150RT (sold)

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    It depends who you talk to, or in this case who responds to your question.

    Rick H.

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    I have serious doubts, the engine will recognize the difference. Depending on where you live and what temperatures you ride in, the 15-50 may actually be a better choice (high temp advantage). I use 20W50 in all my bikes except my old HD shovelhead sidecar rig, which only gets 60W.

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    Unfunded content provider tommcgee's Avatar
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    Quote Originally Posted by BluegrassPicker View Post
    OIL THREAD!

    Will the sun fall fro the sky if I use 15W-50 in my K1600GTL? I have couple gallons left from my RT.
    Every vehicle owners manual I've ever looked at has an oil weight vs. temperature chart.
    Salty Fog Rally 2007, 2009, 2011, 2012, AND LOOKING FORWARD TO 2014!

    -Tom (KA1TOX)

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    Registered User lkchris's Avatar
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    It does and you should check your owners manual.
    Kent Christensen
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    '12 R1200RT, '02 R1100S, '84 R80G/S

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    Registered User bluegrasspicker's Avatar
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    Quote Originally Posted by tommcgee View Post
    Every vehicle owners manual I've ever looked at has an oil weight vs. temperature chart.
    It specifies 10W-40 for warm weather , but says nothing about the sun falling out of the sky...
    Tom Barrie
    http://bluegrasspicker.blogspot.com/
    2012 K1600GTL
    2002 R1150RT (sold)

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    Registered User dmftoy1's Avatar
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    I wouldn't hesitAte in the summer around here but I wouldn't want it in the cold

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    Cave Creek AZ 85k100lt's Avatar
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    Talking Warranty

    Ask the BMW dealer-

    You will Void your Warranty!!!


    All dealers have a viscosity checker if you use the incorrect weight oil they will know right away.

    Believe it!!!

    It's your bike you need to do what is best should not hurt the engine.
    1974 R75/6 W Sidecar
    1989 R100GS


  9. #9
    Touring Rider
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    What a drag

    I agree that it should not hurt the engine, but they specify a certain weight for a reason. At the least, the engine (or at least the oil) will run a bit hotter, and there will be a very slight decrease in fuel mileage.

    Heavier oil is thicker... thicker oil increases friction... friction = heat and drag... heat and drag reduce mileage.

    You may not even notice it, but it will be there. Personally, I'd sell the oil to a buddy who needs that weight, and use what the factory recommends. However, it's your bike...
    Gary
    Casa Grande, AZ
    2011 R1200RT

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    liquid cooled engines generally use lighter oil. They have tighter clearances.

    The flow rate of 15W50 is lower, this can cause bearings to overheat, also reduces and delays the flow of oil to the heads.

    Get the right oil. Odds are it would be fine but risking warranty on a new EXPENSIVE motorcycle over some leftover oil, I would not do it.

    Rod

  11. #11
    Registered User bluegrasspicker's Avatar
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    Sold my RT today and gave the 15W-50 away with it...
    Thanks for the comments..
    Tom Barrie
    http://bluegrasspicker.blogspot.com/
    2012 K1600GTL
    2002 R1150RT (sold)

  12. #12
    Registered User andreb's Avatar
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    Owners Manual

    The owners manual also specifies 10w-50 weight oil. I'd use it in summer months, if I could find a supply. The problem is that it is expensive. The BMW brand 5w-40 is a whole lot cheaper than other 10w-50 and BMW doesn't make 10w-50 motorcycle oil.
    Andre Boening
    2010 F800GS and 2012 K1600GT

  13. #13
    Registered User lkchris's Avatar
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    BMW doesn't "make" any engine oil.

    And, the USA is the only place it sells BMW-labeled oil.

    In the rest of the world, BMW recommends Castrol.

    Here's the chart: http://www.bmw-motorrad.co.uk/media/...66_low_res.pdf

    The six isn't there yet, but I'd guess the recommendation is same as S1000RR, K1300, etc., i.e. Power 1 Racing 5W-40. The USA version of this oil is called Power RS Racing: http://www.castrol.com/castrol/secti...tentId=7040544
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

  14. #14
    Rally Rat
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    Quote Originally Posted by tommcgee View Post
    Every vehicle owners manual I've ever looked at has an oil weight vs. temperature chart.
    I think you mean "oil viscosity vs. temperature."

    The numbers 0, 5, 10, 15 and 25 are suffixed with the letter W, designating their "winter" (not "weight") or cold-start viscosity, at lower temperature.

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    Oil viscosity

    I believe the first number in a multigrade oil is an indication of viscosity grade (weight - not winter) of the base oil without the viscosity improvers (VI). The second number is the resultant weight with the VI additives. Multigrade oils with VI additives maintain a more consistant viscosity as the temperature of the oil changes. Modern engines are designed with bearing clearances and cam/follower profiles that require the multigrade oils. The synthetics also retain a flatter viscosity vs oil temperature and they don't break down as rapidly. However, they still get dirty just as fast and they are just as susceptable to fuel dilution as non-synthetics. I just had a used oil sample from by GTL (5w40 synthetic) analyzed after 5000 miles and the viscosity had dropped from 14.5 to 10.4 due to fuel dilution. Time for an oil change.

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