Results 1 to 3 of 3

Thread: M20 Oil leak diagnosis help needed...

  1. #1
    Join Date
    Jan 2007
    Location
    Granite Bay Ca,20 miles NE. of Sacrqmento
    Posts
    5

    Default M20 Oil leak diagnosis help needed...

    My kid's '90 525/5 started running really rough and dying recently after she overheated it. It starts easy but stumbles and sometimes dies when activating the throttle pedal. I brought it home and began trying to diagnose: Check to be sure the coolant had no signs of oil contamination; cleaned plugs; cleaned AF sensor; checked compression (approx 160# per cyl). I have yet to spray some cleaner on the Crank Pos. Sensor and check the idle ctrl valve.

    I found a streaming oil leak on the Exh. side of the head, which seems to be coming from the fwd side of the #3 exhaust port, right above where the block bulges up like there is an oil passage cast into the block (this "bulge" seems to run from bottom to top).

    Does it sound like the oil leak is from a leaking head gasket due to the overheat, even tho the compression is okay? And The stumble- could that be from a bad sensor somewhere or ICV? Seems to me to be two different problems, am I headed in the right direction?

    TIA

    Mitch

  2. #2
    Join Date
    Aug 2006
    Location
    Jersey, Channel Islands
    Posts
    65

    Default

    Quote Originally Posted by mitchc
    I found a streaming oil leak on the Exh. side of the head, which seems to be coming from the fwd side of the #3 exhaust port, right above where the block bulges up like there is an oil passage cast into the block (this "bulge" seems to run from bottom to top).
    Does it sound like the oil leak is from a leaking head gasket due to the overheat, even tho the compression is okay? And The stumble- could that be from a bad sensor somewhere or ICV? Seems to me to be two different problems, am I headed in the right direction?
    It is looks like gasket gone. The compression can be o.k. because it is leaking from oil gallery (most probably).
    Jan

  3. #3
    Join Date
    Mar 2006
    Location
    Derbyshire, UK
    Posts
    871

    Default

    The stumble could be due to the crankcase vacuum leak caused by the failed head gasket, assuming it is a failed head gasket. Make sure the oil isn't drizzling down from a baked and failed valve cover gasket, which will also cause a vacuum leak.

    1997 535i V8
    5spd, OBC, A/C, cruise, BMW phone, factory M-Tech wheel & suspension, 18" Alpinas

Similar Threads

  1. help needed on a growing fuel leak
    By bigtallsam in forum 5 Series BMW
    Replies: 2
    Last Post: 02-12-2008, 03:25 PM
  2. Got my 3rd E34,need some help on diagnosis
    By takumidrift30 in forum 5 Series BMW
    Replies: 6
    Last Post: 10-18-2006, 12:04 AM
  3. Parts needed for vacuum leak fixing
    By ra_pro in forum 5 Series BMW
    Replies: 2
    Last Post: 05-10-2005, 09:32 AM
  4. Fuel(gas)pipe leak - help needed
    By lotus88 in forum 5 Series BMW
    Replies: 1
    Last Post: 10-10-2004, 05:26 PM
  5. 93' 520i water leak - Advice needed.
    By PVO_Dave in forum 5 Series BMW
    Replies: 2
    Last Post: 04-13-2004, 09:00 AM

Posting Permissions

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