Results 1 to 15 of 15

Thread: K75S Oil pressure light stays on after oil change

Hybrid View

  1. #1
    Registered User detbmw's Avatar
    Join Date
    Feb 2005
    Location
    Deep East Texas
    Posts
    61

    K75S Oil pressure light stays on after oil change

    So I bought my '88 K75S in September and it has been on a buddy's lift ever since. The drive splines were shot and I sent them to Bruno in Canada. Should have them back next week.

    So, in the mean time we have flushed and replaced the coolant, replaced the fuel filter and fuel pump damper, sent the instrument cluster to Austin, TX to have the odometer repaired, and then replaced the instrument cluster and fairing. The back of the bike is still all apart.

    So tonight we put the gas back in the tank and cranked it up and let it run for quite a while. Everything is looking good. Then I drain the oil, replace the filter, and add four quarts of oil. When we cranked it back up, the oil pressure light stayed on, even after a minute.

    Did I break something during the change? The light was not on before the oil change.
    Rich
    Night Black 2000 R1100RT
    Marakesh Red 1988 K75S "The S is, by far, the finest-handling BMW we have ever ridden." Motorcyclist, November 1986

  2. #2
    Benchwrenching PGlaves's Avatar
    Join Date
    Oct 2003
    Location
    "Big Bend" TX
    Posts
    8,717
    Check the oil pressure wending unit wire under the little rubber boot at the oil pump at the front of the engine.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  3. #3
    Aspiring Profligate jeff488's Avatar
    Join Date
    Apr 2007
    Location
    Nacogdoches, TX
    Posts
    794
    Thanks, Paul

    OK, I pulled the wire off the sending unit and the oil light went off.

    Apparently the unit opens the circuit when pressure reaches a certain minimum, but I can't check that on the schematic because SOMEONE took the manual home with him tonight!

    Is there a way to check the unit after removal? Maybe clean it or poke something up in it to free it up?

    If you haven't guessed, the bike is on the lift in my garage.
    '04 Silver R1150RT "Big Oel". '05 Yellow KLR 650
    '00 Red Suzuki Bandit 600
    '65 Allstate/Puch 250 twingle
    "I just want somewhere to ride and food when I get there."

  4. #4
    3 Red Bricks
    Join Date
    Jan 2007
    Location
    Pleasanton, Ca.
    Posts
    3,400
    Wending=Sending


    If the wire to the sending unit is not the problem, I would suspect that there was a problem with your filter. Did the old filter o-ring come out with the old filter? If it stuck to the block and you put the new filter in on top of it, it would blow out allowing all the oil pressure to be dumped back into the sump.

    DON'T RUN THE BIKE UNTIL YOU ARE SURE THAT YOU HAVE PRESSURE!!!!

    Sounds like the oil pressure light is working correctly. Sounds like you don't have pressure. Drain oil, check filter.

    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  5. #5
    Dum vivimus vivamus ted's Avatar
    Join Date
    Mar 2003
    Posts
    2,587
    Quote Originally Posted by 98lee View Post
    Did the old filter o-ring come out with the old filter? If it stuck to the block and you put the new filter in on top of it, it would blow out allowing all the oil pressure to be dumped back into the sump.
    There is a thread here from some time ago with these exact symptoms, and this was exactly what happened. Matter of fact, Lee I think called that one too Now I always check the top of the filter coming out to make sure the o-ring is there. If it isn't on the filter it is stuck inside the engine and you'll need to get up in there to pull it out.

    You might want to go back in, pull the filter and see if there is an o-ring stuck in there from the old filter, or even an o-ring from a filter from a prior change. Remember when putting a filter in, hand tight with a filter cup wrench then 1/2 turn with a socket wrench.
    Ted
    "A good stick is a good reason"
    1994 K75RT
    Moto Pages

  6. #6
    Aspiring Profligate jeff488's Avatar
    Join Date
    Apr 2007
    Location
    Nacogdoches, TX
    Posts
    794
    Checked the old filter and it still has its o ring attached.

    I suppose there could be one stuck up in there from a previous oil change , but wouldn't this symptom have occurred then?

    I would think that those o rings stacked would blow out immediately.

    I guess going back in is the next step.
    But not tonight.

    BTW, thanks for all the responses.
    '04 Silver R1150RT "Big Oel". '05 Yellow KLR 650
    '00 Red Suzuki Bandit 600
    '65 Allstate/Puch 250 twingle
    "I just want somewhere to ride and food when I get there."

  7. #7
    Registered User detbmw's Avatar
    Join Date
    Feb 2005
    Location
    Deep East Texas
    Posts
    61
    Okay, the bike is running with no oil pressure light on!

    Turns out someone (who will go unnamed but I believe he started this thread) fat fingered getting the new oil filter on and it was not seated properly.

    Once again, thanks for the advice.
    Rich
    Night Black 2000 R1100RT
    Marakesh Red 1988 K75S "The S is, by far, the finest-handling BMW we have ever ridden." Motorcyclist, November 1986

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •