E28 Fans

I’m new to the digest and see quite a few questions about E28’s. I had a 528ea for 14 yrs & 280,000km. Bought it new in 1982 and traded it last year for an E39 540ia.

I experienced many of the issues I see on the digest, and more. Before I forget what I did to fix these problems I will share it with you. I am not an expert, so my information may not be as complete as you desire - but hey, this is as good as it’s going to get.

1. Charging lamp on very dimly - could only see at night. Caused by corrosion in the battery cable, just behind the battery clamp. This was the small cable feeding the fuse box.
2. Cruise Control cutting out. Poor electrical contact in rheostat
   • inside actuator unit mounted on the front fender. Take it apart, and use contact cleaner. Caution - there are springs inside, and take a close look to remember the direction of the cable wind up.
3. Cold start problems - turns over, might sputter, but doesn’t start. Usually this is due to the cold start fuel injector (on the intake manifold) not firing. Problem was always the sensor switch. It is the first one at the front - on top of the water thermostat jacket. This switch activates injector if coolant is cold, but also cuts out after a short period of cranking to prevent flooding. This is a mercury switch, and their contacts tend to corrode after awhile. Replace the sensor, or as a quick fix, tap the base of the sensor with a small hammer (percussive maintenance). This usually disturbs any contamination on the contacts, and the sensor will work for a while.
4. Erratic Idle (not Erotic Idol) For several years I experienced idle hunting - sometimes wild swings & roughness. Finally cured by a recall in 85 that upgraded to a new version of the idle control computer and air valve. It also replaced the throttle and removed the purge valve control. But to keep a good idle I also had to do the following each year:
   • - Clean the spark plugs, distributor cap and wiring.
   • - Clean the interior of the throttle body - whip clean.
   • - Clean the dirt out of the idle air valve control (take off - fill with WD40, shake plenty, drain the dirty liquid, dry & replace).
   • - Clean interior of the Air Intake flow valve. (pre HFM)
   • - Remove oxygen sensor and clean with a wire brush - make sure the interior slots are not plugged. Never did replace my sensor and the CO2 readings stayed in limits though out the life of the car.
   • - Always used a brand name gas (I always used Shell sliver)
   • - Changed engine oil 5 times a year, or max every 3-5k KM. In winter I would sometimes change after 1000km. Used Castrol GTX (10w30 winter, 10w40 spring/fall, 20w50 summer) I do not recommend adjusting the air flow meter, the idle valve or the throttle stop unless you know EXACTLY what you are doing since they tend to compensate for each other.
5. Brake pad warning light flickering on bumps. Caused by lead to the rear sensor starting to go open- corroded wire. Dealer installed a sensor with a short lead wire (rather than the one with the long lead). To get it to reach the connector he removed the connector from its support. The cable dangled, and suspension movement eventually caused the wire to deteriorate. I had to cut into the connector, solder splice a new piece of wire, and wrap it in a water tight sealant.
   • - USE THE RIGHT SENSOR!
6. NO STARTER Every so often, usually on a hot day, or after a 2-3 hr drive (even the next morning) the starter would pretend it wasn’t there - not even a click. Dash lights & fuel pump OK, but no starter. I checked the entire circuit many times, - always had voltage on the lead to solenoid, but no start. Wait a while and it would sometimes start. If I did not want to wait I left the ignition on, and used a short jumper wire from battery + to the starter lead (pin 11 in the diagnostic plug) - always started immediately. Obviously there was enough resistance in the circuit to lower the voltage to the point that the starter would not pull in - I checked everything on the + and ground sides and never found it. So - if you have this, at least you can tell your passenger "they all do this", then get out your trusty jumper wire and show what a genius you are.
7. Coolant Disappearing Here is one that I wish I was not familiar with, but, since I see some digest items about dirty coolant I thought I would include it. My coolant was always full when I checked it, but every so often I would get a low coolant warning, and find the coolant down "just a bit". Never noticed any coolant in the oil or visa versa. One night the coolant light came on again, just as I was slowing down from a short burst of speed (160 kph for 3-5 min). Since this had happened before, I waited till I got home (60 km) to check it. This was the wrong time to ignore it. The head had become porous, and through an invisible leak much of the coolant had gone into the crankcase. BMW thought this may have been the ongoing cause of occasional drop in coolant - SO YOU MAY WANT TO CAREFULLY INVESTIGATE ANY COOLANT LOSES. AS MENTIONED IN THE DIGEST - LOOK FOR SIGNS OF TRANSFERS BETWEEN OIL AND COOLANT.
8. Steering Wheel Shimmy Lots of info in the digest on this - occurs when braking from higher speed, or at about 85 kph. It is truly one condition were you can say "they all do that". From my experience there are several items that must be maintained. Wheels balanced, rotors not warped, and most important the lower control arm bushings MUST be in good shape.
9. Rear Wheel Steering - sort of. Another common problem is the mounting bushing on the rear suspension. This is the round canister unit you can see under the body - just in front of the rear wheel well. These eventually begin to fail internally, allowing fore and aft movement. First sign is a slight clicking as you change from forward to reverse, or a better indicator is the seat of your pants at highway speed - over 100 kph. If you lift off the accelerator suddenly and notice that the car seems to twist slightly - then the rear mount is shifting to the point that you now have "rear wheel steering". Leave this long enough and you can eventually do lane changes "real quick" - NOT RECOMMENDED !
10. Blower Whining Sound. The E28 has 2 blowers. The main one is behind the cowl panel (behind the engine) and the AC blower is behind the grill in the centre console. Both mine would whine at times, more so when turning a corner. It’s the shaft bushings. I kept mine quiet by doing the following. Pull out the main fan (remove cowl panel, pull off plastic end caps to the squirrel cage, undo centre holding clamp and electrical connector & pull out ) Spray clean the commutator and bushings with WD40. Repeat yearly. Since it is difficult to pull out the AC blower, I drilled a small hole in the plastic grill - centre of the console directly in front of the fan motor. With the blower running at lowest speed (AC switch on & blower switch off) spray WD40 through the hole - back and forth till fan goes quiet.
11. Musty Smell, and wet rear floor - under carpet. Probably a rear drain tube from the sunroof. There are 4 tubes - 1 at each corner. The rear tubes come down the C pillars and discharge into the exhaust air vent - the outside vent panel on the pillar. If a tube has shifted it may drain inside the car, or if it is blocked with dirt so that water froze in it, then it cracked and is now leaking. These need to be cleaned periodically with a long wire. Check by pouring some water through - should come out the bottom.
12. Fuel Leaks:
    • - fuel tank - had it relined - works great.
    • - hoses from tank to pump, and pump to metal line. - these go porous and start to leak - replace if more than 8 years old.
    • - fuel line as it crosses the rear underbody - corroded since it was not cleaned very often like the ones along the side.
    • - cold start injector - you will smell fuel in car.
    • - T connector in fuel line to the fuel rail - replace connector, and install clamps on the fuel lines at all connections.
13. Instrument Lighting The amber lighting of the instruments becomes dimmer as the bulbs age. Replace the 2 bulbs in the back of the instrument cluster every 3-4 years - you will notice the improvement.

Modifications are in separate posting.

Cheers
Jim Cash
London Ontario Canada
519-657-4839 - j.cash_at_sympatico.ca

current E39 540ia