OIL FILTER HOUSING LEAK REPAIR

1998 - 528i (Tip applies to All E39 528's) by Bryan H

Getting Started:

Remove the battery positive terminal from the battery. (YOU MUST DO THIS)

1. Remove the Air cleaner assembly and air meter by removing the a) 10mm
bolt b) 2 clips c) and loosen band clamp d) remove screw below arrow
shown. Disconnect electrical connector to air meter. Arrow 2 shows
alternator. Arrow 1 shows oil filter housing (This is what we are
after). See Picture1 (above)

2. Remove the plastic covers (they pry off) on the spring loaded belt
tensioner and the idler pulley with jewelers or other small screwdriver
located just above alternator. Use 5/8 socket and ratchet to apply
downward pressure on the tensioner pulley and slide off the belt from
these pulleys and the alternator pulley. Use 13mm socket and remove the
idler pulley, notice how the tab and notch fit together on the back of
this pulley. (Sorry, no pictures) This is also the bolt that attaches
the top of the alternator to the oil filter assembly.

3. Use 5/8 socket and remove alternator bottom bolt. Unplug wire at
back of alternator and peel back rubber and using 12mm socket remove
battery cable from alternator (This is why you disconnected the
battery). Push these wires back out of the way. Pull the plastic air
cooling duct from the back of the alternator and then rock the
alternator back and forth and pull it from the car.
On the workbench remove the two screws holding the black plastic duct
onto the back of the alternator. Clean out any leaves debris and
replace. See Picture 2

Arrows show debris, and air flow to alternator.

4. Use 13mm and remove the two bolts that hold on the Power Steering
fluid tank and move it out of the way. We will deal with it later.

5. Picture 3 shows the Oil Filter Housing without the power steering
tank and the alternator. Arrow 1 points to where the oil leak would
show. Arrow 2 points to the alternator mountings and arrow 3 points to
where the tension pulley mounts. I removed it to check the bearings. If
yours rolls rough, now is the time to get a new one.

6. Now lets remove the Oil Filter Housing from the engine block. See
Picture 3. Using 13mm remove two bolts to power steering pump bracket
(See yellow arrows). Using ¾ box wrench remove banjo fitting to oil
supply hose (See yellow arrow) and unplug wire to oil pressure sending
unit. Remove the six bolts shown with yellow dots on them. Gently tap on
the housing or using a large screwdriver or tire iron pry gently on the
top of oil filter housing and it will loosen. Rock the housing out of
the power steering bracket letting the housing pivot at the bottom and
remove it from the engine. Now this is what you have left. See Picture 4 (above)

7. In Picture 5 (above), arrow 1 points to the banjo fitting oil line to the top
of the engine. Arrow 2 points to oil passages from the Oil Filter
Housing to the engine block. Arrow 3 points to radiator overflow tank I
removed and moved out of the way. I figured out you don't have to mess
with the fan, shroud or any of that.

8. Picture 6 (above) shows the Oil Filter Housing on the bench. Notice I didn't
remove the filter. Also notice I made a paper template and punched the
bolts in the same pattern as the Filter Housing so I would remember
which holes the bolts came out of so I would put them back in the same
hole (In red circle). Yellow arrow points to idler pulley and alternator
top bolt. Purple arrow points to tensioner pulley and where it mounts.
Red dots are the six boltholes.

9. Picture 7 (above) shows the engine side of the housing. Green arrow is where
the filter is. Red dots are the mounting boltholes. Blue arrow shows
void space. Purple arrow points to oil pressure sending unit. Red arrow
points to plugs in the casting that are weeping small amount of oil. I
put a thin coat of black sealer on them to slow down the weeping. Yellow
arrow points to backflow valve. Keep this clean and dont damage it.
Notice the deep groove where the formed gasket goes. Clean all the
excess oil off of and out of this groove. Install the new gasket and be
sure to push it down into the groove evenly. It should barely stick up
out of the groove when finished.

10. Picture 8 (above) shows the banjo bolt and alumn. Crush washers (yellow
arrow), the formed gasket ($23, blue arrow), the power steering pump
bracket bolts (red arrows), the bottom alternator bolt (green arrow),
and the belt idler pulley and tensioner pulley (purple arrow).

11. Clean the engine mounting area clean as shown in Picture 9. Apply a
small amount of sealer, just a film, on the flat surfaces. Notice the
two alignment pins in the lower left bolt position and the top right
position. The wavy arrows indicate where the oil leak film was and where
the oil would go down the side of the engine.

12. Install the Housing back onto the engine block in reverse of the
removal process. Start by inserting the bottom of the Housing into the
power steering mount and rocking it onto the engine. BECAREFUL and make
sure you use the alignment pins in the bottom left and top right
boltholes to align the housing with the engine block. Push on snug and
install the six bolts as shown with yellow dots in Picture 3. Tighten
just snug with a ratchet. Using a torque wrench, tighten to 10 ft.lbs.
In a crossing pattern first. Then I tighten them to 24 ft.lbs., doing
the bottom left, then the top right (remember the alignment pins?) and
then continued in a crossing pattern. NOTE: The best spec. I could find
for these bolts was 16 ft.lbs. But it still leaked. My BMW Mechanic
friend said M8 bolts could go only as high as 26 ft.lbs. Also depending
on the length of the socket extension you use could also affect the
torque wrench settings. I would investigate this completely and use a
setting particular to your setup.

13. Now that the Housing is on, now is a good time to remove the factory
clamps on the bottom of the power steering tank and replace them with a
screw type to stop leaks. Take the top off the tank, pour the fluid in a
container, and remove the factory clamps. Remove the hoses and pour out
the little left in the hoses. Clean everything up, and dry out the
inside of the hose where it will go back on the tank nipples. Apply just
a film on the nipples, just behind the ridge, where the clamp will be on
the hose. Leave the ridge clean and dry. Put the screw clamps over the
hose and slip it on the tank outlets. Tighten them appropriately.
Picture 10 shows the factory clamps to be replaced.

14. Now install the new alumn. Crush washers on the banjo bolt and
install the oil hose back onto the Housing. Tighten appropriately, not
too much. Install the electrical connector back onto the oil
pressure-sending unit. In Picture 11, the dots are the bolts to be
torque. Arrow 1 points to the banjo fitting. Arrow 2 shows where the
banjo fitting goes, and arrow 3 points to the oil pressure-sending unit.

15. Now replace the two power steering bracket bolts. Replace the
alternator remembering to attach the battery cable with the rubber cover
and then the electrical connector on the back. Connect the air-cooling
duct to the back of the alternator. Install the bottom alternator
mounting bolt and then the top bolt with the idler pulley, remember the
tab on the back of the pulley and align it with the recess.

16. With a 5/8 socket and ratchet, apply downward pressure on the belt
tensioner pulley and install the belt to its original alignment.

17. Mount the power steering fluid tank back onto the Housing using 13mm
socket. Put in new power steering fluid to its proper level. Picture 12
shows screw type clamp used on power steering fluid tank.

18. Replace air filter housing and install screws, clamps, and clips as
shown in Picture 1. Make electrical connection to sensor in air intake.

19. Check all connections and look for tools. You should be done. I hope
this works for you. I have not had a leak here after replacing the gasket.