BlueHorse

I have had a slow oil leak in last 12 months on my 2004, 525i.

Thought it was stripped oil plan plug, but today crawled under the car and noticed the leak came from a higher location. Basically, to the left side (driver side) of the oil pan, at the top facing up, there is a rubber hose coming out of the oil pan (I think that is the upper oil pan?). This hose immediately splits into two hoses. The one goes to the left has black fiber material shielding it starting from a few inches away. The oil leak appears to be where the main hose connects with the oil pan top surface. Attached are a few pictures.

The hose going straight up is pretty clean and no oil dripping down from there. I am not sure how clean the hose going to left is, and whether there are traces of oil dripping down along its line. The last picture below does seem to show some oil on this lefty hose (at the bottom only, so might be spill over oil), but when I was down there I did not see that. I did not use hand to feel hoses to confirm if the higher end of them are clean, and for that I am hitting my head now.

1. Is the aluminum block in the pictures the upper oil pan?
2. What are those two hoses? Where are they going, esp. the hose going to the left? Wander if that hose going to the left could be leaking? I probably need to go in there to take another look again.
3. From the pictures, would you think the leak comes from where the main hose connects with the oil pan?
4. Any idea if this is a DIY to fix? And wander how much roughly it could cost to bring to a shop?

Thanks!

BlueHorse

Oh, one clarification, the pictures were taken from the front wheel driver side facing the engine, so the hose going left is actually going to the front of the car. I am wandering if it is moving (or receiving) oil to the radiator for cooling.

DavidF

The metal tube assembly is sealed to the oil pan with an o-ring and it held in place with a tab (up higher) bolted to a bracket. The verticle tube is for the oil dipstick. The other tube coming off the side is for the crankcase ventilation valve to drain oil back into the sump. The crankcase ventilation valve is a bear to change and not a job to start DIY fix. More than likely, the rubber hose from the valve to the metal tube is what is leaking...they get soft.

BlueHorse

David, can you point out where the metal tube is in my picture? I can't see it.

Regarding the comment above, should the entire rubber jose from valve to the metal tube be replaced, or only a section of it can be cut off and connected with a new short hose?

Any idea how much cost to have a shop to do it, or a dealership?

BlueHorse

I am going to take another look, and see if the rubber hose going to crankcase is leaking. If it is leaking where it joins the metal tube, my plan is to drain the oil, and cut that section of the rubber hose, and re-attach the rest rubber hose back to the metal tube. Then tighten up with a clamp. Any thoughts this may or may not work?

DavidF

Not sure why you asked where the metal tube is in your picture and then you talk about the metal tube. the dipstick tube is metal along with the portion "y"ed off for the crankcase ventilation valve. I think you need to replace the entire rubber hose and, while you are at it, replace the failure prone crankcase ventilation valve.

BlueHorse

Thanks David. I guessed where the metal tube is after I sent my follow up question. Sorry for the confusion.

As you mentioned, there is an o-ring where the metal tube joins the aluminum block. Could that be where the leak is? That was my guess when I first saw and sadly I did not double check if there is oil along the tube branching forward. Googled Oil Dip Tube and found some E39 owners replaced their o-ring. Not sure why or how. Seems to be an easier task to start IF I am not sure where the leak is exactly.

DavidF

Yes, replacing the o-ring might be the easiest task. You will need to unbolt the dipstick tube from the bracket support and try to lift the tube out of the "block". The tube is inserted into the block about an 1.5" or so. The o-ring slips over the end of the tube.

BlueHorse

I saw one bracket holding the oil dip stick tube in place. Seems pretty hard to access. Anybody removed it on E60 M54 model before, pls give me some tips on how to get there.

Maybe time for me to shop for a Bentley manual...

BlueHorse

Turns out the hose between CCV and the dip stick tube was leaking where it connects the CCV. Unplugged a few harnesses (to the oil filter housing, alternator, and two others) so I can reach the hose at the CCV end. The hose felt like melting chocolate and my finger could feel a cut even with gloves on. Bought replacement hose from BMW dealer for $40. The end connecting the dip stick tube can be accessed after taking off the plastic guard covering the CV boot. I had to use a utility knife to carefully cut the old hose in order to pull it off from the tube. Coated the inside of the hose with a bit new engine oil before push it over the dip stick tube. The other end of the hose has plastic retainer, just push in till it clicks. Then cleaned the area.

Drove 30 miles so far, no oil leak found as of now.

If there were oil leak from the o-ring, one can access the bracket holding the dip stick tube by same step of removing the splash guard covering the CV boot.