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Discussion Starter · #1 ·
I have seen several posts where the hose coming from the front of the valve cover going to the oil separator was damaged during removal of the valve cover. Below is DIY on how to replace the hose out of a 2001 325i.

This replacement can be completed in 30 min to an hour.

Background: the plastic hose gets brittle with age. The older the car, i.e. more than 7 years old, the more likely it will be brittle. If your car is older than 7 years, I recommend replacing the oil separator and all associated hoses to the separator. Failure timeframe for cars in northern or colder climates are shorter than given. The extreme hot and cold cycle shortens the life expectancy of the plastic components. Should you decide to do the oil separator as well, check this out: http://www.bimmerfest.com/forums/showthread.php?t=323335

Warning: The older the oil separator, the more likely it could break doing this procedure. However, the plastic to the oil separator is thicker compared to the hose so it should be more durable. Do this project at your own risk. All information given are for reference only.


Dissassembly

Remove front air duct

  • Remove 3 plastic expanding fasteners. Raise middle pin and pull out expanding fastener.
  • Remove air duct

Remove air filter box assembly

  • Remove 2 10mm bolt holding the air filter box assembly
  • Disconnect the electrical harness to the MAF sensor
  • Loosen hose clamp between MAF and upper air intake boot

Set aside the power steering reservoir assembly

  • Remove the 2 bolts (13mm) holding the power steering assembly
  • Move steering reservoir out of the work area

Disconnect 4 electrical connectors

  • Oil pressure sensor
  • Alternator (depending which alternator came with your car, this may not apply)
  • Fuel breather valve
  • Oil temperature sensor

Move fuel breather valve to increase access area

  • Disconnect lower fuel breather valve hose from clip
  • Remove fuel breather valve from mount bracket

Optional. If you have large hands or need more room, remove the oil pressure switch. Use an adjustable wrench to take it out. Tip: Scribe a line across the nut to the frame using a marker. During installation, you have a reference mark on how much torque to use. Do clean the copper washer and mating surface before installation. It is best to replace the washer, if available. Dimension of washer: 16.1mm o.d., 11.7 mm i.d.


We now have more room to access the lower connector with the electrical wirings and fuel breather valve assembly out of the way. Pictue 2.

The upper and lower hose connectors are identical. Study, understand, and practice on the upper connector how it works.

Squeeze the ring by the ribbed section of the connector ring and pull connector out. These ribbed sections are on opposite sides of the ring. If you run into any difficulty, the rubber o-ring seal may have seized. Twist the connector slightly clockwise and counter-clockwise from its pivot point to dislodge any obstructions.

Connecting the new hose is simple. The 90-deg. elbow of the hose goes to the valve cover while other end connects to the oil separator. Push the connector in until you hear it snap. Pull lightly to be sure the connection is secure.
 

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Thanks for the excellent write up :thumbsup:
The hose elbow of my 01 330i was completely destroyed as you said, while doing the valve cover gasket. It's now held on by gorilla tape and zip-tie. I'll have to do this soon.
 

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Thanks here for the write up too - I shattered mine on Saturday and it's held together with some insulation tape at the moment, need to do a proper replacement really!

Don't suppose you have the part number for the replacement pipe handy?
 

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Same thing happened to mine while changing the valve cover gasket. Getting the valve hose disconnected from the oil separator was not very easy and I was afraid of causing a leak or breaking the oil separator. I followed the DIY instruction but I used my soldering knife to cut off the locking mechanism of the old valve hose then I wiggled it off very carefully. Luckily, I did not burn myself or anything else close to it. It was a success!!!
 

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Discussion Starter · #6 ·
I followed the DIY instruction but I used my soldering knife to cut off the locking mechanism of the old valve hose then I wiggled it off very carefully. Luckily, I did not burn myself or anything else close to it. It was a success!!!
Wow, good thinking!
 

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Thank you sir! I will be using this in a few days when my new valve cover vent hose arrives.

Experience note: This vent broke when I replaced my Vanos Seals about 1 year ago. The hose cracked, and I secured it with black electrical tape. It worked! But is starting to fail now about 1 year later. If I used a lot more tape I could make it last a few more years, but its time for a real fix and not a band aid.
 

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It's difficult to disconnect that hose from the valve without breaking the valve. The valve can be very brittle and any force on it will cause it to crack. This is my experience.
Taping over the crack with electrical tape is very functional. He could even leave it like this till something else cracks in the system.

This is just what I think.
Rajaie is the brains behind the Beisen system seals.

Reading that makes me not want to touch this repair.

What do you guys think, is it worth replacing this 1 hose, or should I just put a crap load of black tape on it?

140k miles on this car, I suspect the O-Ring will be plasticized.
 
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