Announcement

Collapse
No announcement yet.

M3 E46. Oil leak / Origin?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    M3 E46. Oil leak / Origin?

    Hi All!

    For the last 2-3 years we have had an oil leak somewhere under the hood that drops into the botton plastic protector, even through the sway bar. This leaking only happens when a reasonable number of kilometers are driven. Not when 5-10km.

    We firstly replaced the top gasket in the motor and the top part of the motor is dry since then. However, oil kept dripping. So we replaced the oil filte housing o-ring. Later it was the time for a bolt in the back side of the motor that seems useless (kinda as to cover a casting hole or similar), and the backside of the motor never was humid again.
    Since the oil pan was really wet, the next to be replaced (in last Christmas indeed) was the related gasket. But we kept having oil in the lowest corner of the oil pan to motor connection edge. So we added some silicone to that corner to grant (or try to grant) this would not leak. But the oil dripping persists... and such an oilpan-motor edge is still wet over the silicone.

    A couple of days ago we cleaned the best we could with brake cleaner to try to identify any fresh oil coming out, but it is not possible to remove all the dirt without disassembling many parts. The vanos lower area seems to be dry (still dirty though). So we wonder if the problem could still be the oil pan gasket, or maybe the cylinder head gasket? The oil is dripping from the mid-front left side; this is clear.

    I tried to provide some pictures in case these help, but cannot find how to load them from the PC... I am sorry for this.

    Any suggestion on how to identify the origin of the leak? Where this may come from?
    Thanks a lot!
    Kate
    Last edited by Katerin; 04-22-2023, 12:15 AM.

    #2
    Drop the pan and get under the car and see what is went, and what is dry. Then start zeroing-in an the source.

    Comment


      #3
      Originally posted by Estoril View Post
      Drop the pan and get under the car and see what is went, and what is dry. Then start zeroing-in an the source.
      We tried looking from underneeth (and also from the top) the car many times, but there are some tricky places where it is not possible to see properly, or even see at all... By touch, we suspect it could be the cylinder head gasket lower corner, but cannot confirm though. Is there any way to reach those tricky areas without dismounting all the front?

      Comment


        #4
        Post all your photos here too if you're going to post in multiple places.

        Comment


          #5
          Check the CPV

          Comment


            #6
            Inline with about cylinder 6, about 10cm down from the head gasket is the CPV which is a very common source that will coat the entire rear and make the oil pan appear to be leaking.

            Was silicone added to the proper spots during the oil sump gasket replacement? Who did the work?
            This is my Unbuild Journal and why we need an oil thread
            https://nam3forum.com/forums/forum/m...nbuild-journal

            "Do it right once or do it twice"

            Comment


              #7
              There's no shortage of locations on these motors from which oil will seep. In my experience (and from reading), common sources include:
              • Valve cover gasket
              • VANOS high-pressure line (can develop micro cracks)
              • VANOS gasket
              • CPV (video)
              • Oil separator return pipe (valve cover connection)
              • Timing chain tensioner (can loosen and back out)

              Comment

              Working...
              X