Getting EDGEucated: The “75k Mile List”
E38 7 Series (1995-2001) Edition
After years of working on BMW’s, we have begun to see common problems and maintenance concerns that need to be addressed on nearly every middle-aged BMW. Like all BMWs, 7′s have certain areas that need to be inspected regularly, and prospective owners should always have a pre-purchase inspection done to verify the condition of these items.
In this list, you will find items that should have been replaced or at least inspected by 75k-100k miles. Some are model specific, and will be noted as such.
Areas of Concern:
Thrust Arm Bushing Failure
The most common suspension problem on the E34. Common symptoms for torn or cracked thrust arm bushings are shimmy under braking at freeway speed. vague or rubbery feel in the steering, and excessive front tire wear. Extreme examples will also produce a clunking sound. EVERY 5 and 7 series car we have ever seen needs these replaced by 75k.
Tie Rod Wear
5 and 7 series cars share the same basic front steering components, consisting of a tie rod end attached to each end of the center tie rod. All three components contain ball joints and any one of them may cause steering shimmy. If any of the ball joint boots is cracked (you’ll see grease coming out) then expect that component to need replacement. All components should also be checked for excessive play, and replaced if out of BMW spec.
Worn or Blown Shocks and Struts
Factory BMW shocks work great for about 30k. By 60k they are completely shot. Most folks who have been driving their cars since new hardly notice the deterioration as it is gradual. Symptoms include:Diving under braking and acceleration, excessive lean and suspension compression during cornering. Bouncy and uncomfortable ride. Shocks and struts may visibly leak shock oil. EDGE generally recommends replacing the factory units with quality shocks from Koni whenever possible. When replacing shocks and struts, keep in mind it is a great time to install lowering springs or freshen up other areas of the suspension. You will be amazed at the difference a good set of shocks can make in both comfort and performance!
Worn or Failed Swaybar Endlinks
Worn swaybar endlinks can compromise handling. A worn swaybar can sound like a metallic clicking noise. There is no critical danger in a failed swaybar endlink, but the handling of the car is compromised.
Torn Subframe and Subframe Bushings
Torn or Worn subframe bushings may lead to subframe failure. Common symptoms of subframe failure are erratic handling and unidentified clunks, squeeks and bangs from the rear of the car. Early detection of a torn or cracked subframe bushing can prevent costly subframe repair and welding.
Ripped or Failed Guibo
A torn guibo (Flex Disc) will result in a perceivable ‘drivetrain elasticity.’ Acceleration will be preceded with a loud clunk as the guibo bolts bind together.
Dirty Automatic Transmission Fluid or Clogged Filter
Hesitation and/or hard shifting could be the result of dirty and old automatic transmission fluid or clogged transmission filter.
Water Pump Failure
Water pump failure is without a doubt the easiest way to cause extensive and expensive damage to your BMW. The main symptom will be a rapidly overheating motor. What occurs is that the bearing or impeller on the stock pump, breaks, completely disabling the cooling system. If you ever see the temperature gauge on your BMW climb above the 3/4 mark.
TURN THE CAR OFF IMMEDIATELY AND CALL A TOW TRUCK!!
We can’t stress this enough. Failure to catch the overheating motor in time can result in a warped head or even more severe engine damage. We recommend changing out the waterpump in six cylinder cars every 60-80k.
Cracked Radiator Necks
BMW loves their plastic radiator tanks….Unfortunately…The plastic around the radiator necks become brittle and crack with age, often without warning (see warning above.) Radiators should be thought of as 80-100k mile wear items. Trust us, this is cheap insurance!!
Fan Clutch Failure
Most fan clutches fail between 80 and 100k miles. They provide the primary cooling for your car, and are easy for us to diagnose.
Accessory Belt and Tensioner Failure
Worn tensioners and idler pullies will sound like a squealing noise from the engine bay. Belts should be inspected for cracks regularly. If a belt happens to snap, the cooling system will fail as the water pump will cease to operate. Power steering and the alternator will also fail to work. Again, pull over and shut the car off immediately should you suspect a belt failure or see the temperature gauge rise past the 3/4 mark.
O2 Sensor Failure
Poor mileage, poor idle and flat spots in the power curve could be caused by bad O2 sensors. Even if your car isn’t throwing a check engine light, they may not be performing optimally. BMW recommends replacing the O2 sensors every 100k miles. Extended high-RPM running/racing and high-performance chips may shorten the replacement cycle.
Electrical Relay Issues
The relays throughout the car were soldered with an automated process that wasn’t designed with solid-state components in mind. The lugs on the relays, especially those for the headlights (located in the LKM) and the taillights (the mustard relay) are much more massive and never got enough heat or solder to form a good joint at the factory. They can easily be resoldered, saving over $400 for the LKM or $60 for the mustard-colored relay. (Thanks to MichaelY)
Power Seat Issues
The cable- housings in the power seat assemblies also stretch, creating all sorts of problems. (Thanks to Michael Y) Parts are readily available, but somewhat pricey. We recommend this as a DIY project as paying someone like us to fix a problem like this can be quite pricey!
If the flow of air out of the air conditioning and heater system is not as strong as it used to be, it strongly suggests the pollen microfilter of your car has become dirty and clogged over time. A damp and musky smell can also indicate a dirty filter. This is a service II replacement item.