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Thread: 1991 e32 735i pan gasket replacement m30 engine

  1. #11
    Join Date
    May 2004


    Comment from Gale after I posted it on another forum: Good info, Thanks Erich. I've done this twice now, once on my 735i and once on my sons 535i. Both times I combined the job with a full upper/lower control arms, idler arm, and tie rod replacement. Dropping the subframe was worth the extra minimum effort for full easy access to the pan gasket.

    Trick: when dropping the subframe, pre-lube the nuts in the chassis by removing the plastic plugs from above and soaking with PB Blaster or 50/50 acetone-ATF mix a few days in advance, 3 on each side. The subframe locator dowels will be rusted in place. Put a crushable cardboard box under the subframe and knock it loose from above with a heavy sledge hammer.

    and one more info from a former site of a member here, recovered with the wayback machine:
    M30 Oil Pump removal and rebuilding

    Lubrication is critical for any engine. Good condition of the oil pump is essential for provision of adequate lubrication. Negligence of timely oil changes affects oil pump as well as the rest of the system resulting in permanent wear. Here I provide simple procedure for removal of the oil pump from M30 engine without the need for engine lifting hardware. I also show internal parts of the pump in order to provide information on what needs replacement in oil pump rebuilding procedure...
    Components of oil pump:
    Clockwise from top left corner:

    - Main body of the pump
    - Rotor housing
    - Bolts
    - Inner rotor
    - Outer rotor
    - Gasket

    Worn out get four parts:
    1 - Rotor housing - this is seen on the picture as light color discoloration inside the cavity. As the part rubbed against the rotors that spun inside, the outer layer of the cavity lining got shaved off.
    2 - Rotors - both inner and outer rotors get to be worn especially at the sides. As mentioned one side of each gets to rub against the housing cavity. Other side of each gets to rub against the gasket.
    3 - Gasket...

    Minor Theory...
    hown above is the position of the rotors inside the housing. Both spin about own center, counter-clockwise. The shapes are matched in such manner that three cavities that are created are mutually liquid tight avoiding leakage and consequential low oil pressure. Once the gasket is placed on top, the biggest cavity creates a chamber bearing the brunt of oil delivery. The cavity on the right is shown in the position of creating suction. After the oil is replaced during the change, the suction is pneumatic during first few cranks of the engine. It is obvious that suction is created - spinning counter-clockwise this cavity is expanding while turning into the position of the biggest one on top. As the rotors turn, the biggest cavity contracts while turning into position of the cavity on the left, expelling the oil.

    Shown above is covered rotor cavity by the gasket that precedes main oil body during assembly. Top rotor cavity is fully enclosed providing liquid tight chamber for oil translation within the pump.

    On the condition of the parts...

    Scored rotors must be replaced as they are incapable of provision of desired oil pressure. The rotors shown below are scored as well as worn to the point of being narrower than specifications call for. The rotor shaft having been grabbed could be moved alternatingly forward and backward within the pump before the desassembly.

    The rotor housing must be replaced as well. The chain that pulls oil pump sprocket creates torque about the point that sits the butt of inner rotor within main body of the oil pump. Pulling the axis up, the chain forces the rotors to rub more against bottom half of the housing creating clearance with time.

    The gasket must be replaced as well, it is intermediate part that participates in movement. It may be noted that sealing of the chamber created on top of the housing may be imperfect as the gasket provides small openings on both ends of the chamber. Designing custom gasket that ensures good coverage of that chamber by 1/32 of an inch may be interesting idea.

    Pump removal...
    I used this technique by myself a couple of times on the street in order to expose and remove oil pump of m30 in e34:

    1 - Set the engine at TDC of cylinder #1
    2 - Dismount the exhaust by removing the hangers at the resonator and the muffler.
    3 - Drain the oil.
    4 - Disengage connectors for these sensors - oil pressure, idle control valve, coolant level.
    5 - Dismount coolant expansion tank and push away to the left.
    6 - Remove the plate that supported coolant expansion tank.
    7 - Remove top nuts from engine mounts.
    8 - Raise the car onto jackstands supporting at front mounting points.
    9 - Disconnect exhaust at transmission.
    10 - Remove the bolts that mount oil pan to transmission. Regular 8mm socket will do.
    11 - Remove 10mm bolts along the perimeter of oil pan.
    12 - Disengage the connector for oil level sender.
    13 - Disengage steering pump from its bracket and push away to the left.
    14 - Remove steering pump bracket.
    15 - Remove bottom nuts from engine mounts. KEEP the mounts in place.
    16 - Use the jack under front cross member to raise the car.
    17 - Remove jack stands, placing one to support the engine directly under the engine mounting BANK for the bracket of air conditioning compressor.
    18 - The jack stand should be extended about a foot and a half for sufficient room.
    19 - SLOWLY drop the car, observing placement of compressor bracket and coolant expansion tank. The engine should not move too much to the side as the car is lowered. Drop only much enough for the engine to stop moving with respect to the car. The jack must be under cross member supporting the car. Lift just a bit to make sure that the car's body does not recline on the engine BUT is fully supported by the jack.
    20 - With enough extension of jack stand the engine rises with respect to the car providing enough room to remove oil pan through minor maneuvering.
    21 - Withraw the pan.
    22 - Slowly raise the car using the jack at cross member. Watch for engagement of engine mounts with engine stands.
    23 - Remove jack stand, place both jack stands at front mounting points, and drop the car on them.
    24 - Undo the nut that holds oil pump sprocket, and slowly pull the sprocket off the rotor shaft.
    25 - Undo 3 bolts that secure oil pump to the engine, finalizing removal of the sprocket off the rotor shaft.

    Remember: I bear no responsibility for negligent and/or harmful actions of individuals in relation to this information...
    Last edited by shogun; 02-29-2016 at 09:30 AM.

  2. #12
    Join Date
    Dec 2003
    Eastern Tennessee USi


    Pictures would help.
    95 E34 530I V2.37
    Those who make peaceful revolution impossible will make violent revolution inevitable.

    John F. Kennedy

  3. #13
    Join Date
    May 2004


    pics are in the link I posted above from wayback machine

  4. #14
    Join Date
    May 2004


    Reparaturanleitung / Motorschmierung / Ölpumpe aus- und einbauen/prüfen / M10/M30 Motor
    Befestigungsmuttern für Antriebskettenrad abschrauben und Kettenrad abnehmen. Paßscheibe abnehmen.
    Ölpumpe abschrauben und herausnehmen - Pfeile-. Vorher gegebenenfalls Sicherungsbleche an den Schrauben durch umbiegen öffnen.
    Antriebswelle der Oelpumpe von Hand drehen und dadurch Oelpumpe auf Leichtgängigkeit prüfen. Oelsieb in Kraftstoff reinigen. Ölpumpendeckel abschrauben und Gehäuse sowie Rotoren auf Riefen und Abnutzung prüfen. Mit Fühlerblattlehre Radialspiel zwischen Außenrotor/Pumpengehäuse prüfen. Sollwert: 0,1 - 0,15 mm. Axialspiel Rotor/Pumpengehäuse mit Lineal und Fühlerblattlehre prüfen, Sollwert: 0,04 - 0,1 mm. Spaltmaß zwischen Innen- und Außenrotor wie in der Abbildung gezeigt prüfen. Sollwert: 0,12 - 0.20 Mm. Gegebenenfalls Oelpumpe ersetzen. Ölüberdruckventil aus der Oelpumpe herausnehmen. Kolben auf Leichtgängigkeit prüfen und Länge der Druckfeder messen. Sollwert in entspanntem Zustand: 68 mm.
    Überdruckventil mit neuem Dichtring einsetzen. Ölpumpendeckel anschrauben. Ölpumpe ansetzen, dabei neuen o-Ring zwischen Gehäuse und Oeldruckleitung einsetzen. Darauf achten, daß die Oelbohrung im Distanzblech mit der Oelbohrung im Motorblock fluchtet. Kettenrad in die Antriebskette einsetzen und auf die Pumpenachse aufschieben. Paßscheibe auf die Pumpenachse aufschieben. Befestigungsmuttern für Pumpenrad mit 9 nm festziehen. Pumpe mit 22 nm festschrauben. Spannung der Antriebskette durch Daumendruck prüfen. Bei leichtem Druck muß sich die Kette etwas eindrücken lassen. Achtung: die Kettenspannung wird durch unterlegen mit entsprechender Anzahl Distanzbleche - 1 4 - zwischen Pumpe und Motorblock eingestellt, siehe Abbildung w-1216. Wenn die Spannung der Kette zu gering ist, dickere Distanzbleche einbauen. Ölwannenunterteil einbauen. Link mit Zeichnung
    Repair instructions / Engine lubrication / Remove and install/check oil pump / M10/M30 engine

    Unscrew fastening nuts for drive sprocket and remove sprocket. Remove shim washer.
    Unscrew and remove oil pump - arrows-. If necessary, open the locking plates on the screws beforehand by bending them over.
    Turn drive shaft of oil pump by hand and thus check oil pump for smooth running. Clean oil strainer in fuel. Unscrew oil pump cover and check housing and rotors for scoring and wear. Check radial clearance between outer rotor/pump housing with feeler gauge.
    Nominal value: 0.1 - 0.15 mm.
    Check axial clearance rotor/pump housing with ruler and feeler blade gauge, nominal value: 0.04 - 0.1 mm.
    Check gap dimension between inner and outer rotor as shown in the figure. Nominal value: 0.12 - 0.20 mm.
    If necessary, replace oil pump.

    Remove oil relief valve from oil pump. Check piston for ease of movement and measure length of compression spring. Nominal value in relaxed state: 68 mm.

    Insert pressure relief valve with new sealing ring. Screw on oil pump cover. Fit oil pump, inserting new o-ring between housing and oil pressure line. Make sure that the oil hole in the spacer plate is aligned with the oil hole in the engine block. Insert the sprocket into the drive chain and push it onto the pump shaft. Push the shim washer onto the pump shaft. Tighten the fastening nuts for the pump sprocket with 9 nm. Tighten pump with 22 nm. Check the tension of the drive chain by thumb pressure. It must be possible to press the chain in slightly with light pressure.

    Caution: the chain tension is adjusted by placing the appropriate number of spacer plates - 1 4 - between the pump and the motor block, see figure w-1216. If the chain tension is too low, install thicker spacer plates. Install oil pan lower part. Link with drawing
    Translated with (free version)

    The German repair manual from Bucheli for the E32 series has following info for the oil pressure for the M30B30 and M30B35
    oil pressure in idle 0.5-2.0 bar
    oil pressure at max RPM 4.0-6.0 bar.
    radial tolerance outer rotor/pump housing 0.1-0.15mm
    axial play
    rotor/pump housing 0.04-0.1mm
    space inner/outer rotor 0.12-0.20mm
    length of the over pressure spring without tension 68mm

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