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BMW E28 Five Series - Problems & Buyer's Guide
Body & Fittings
A common rust spot is the front of the footwells. These get all the splashback from the wheels and it shows. Ensure yours are well undercoated if they're still OK.
The rear shock towers are a common weak spot in old BMWs but the E28 isn't as bad as the 2002 or E21, worth a check though. I'd also remove the rear seats and check underneath.
If the door drains clog the bottom of the door will rust out. Rust can also start behind the trim strips on the door where the metal is perforated but this can be stopped if caught. It's not a biggie on the E28 but worth a check.
If the sill drains clog the sill will rust, they start at the back.
Check the four sunroof drains aren't rusty as they are very difficult to fix if they leak. If they become clogged you'll get water in the footwells. A bad windscreen seal can also cause this.
The chrome effect plastic lock strip on the rear window fades badly, any competent windscreen installer can renew it cheaply.
If the electric windows are slow it's due to lack of use. Get some silicone spray with a straw attachment and use it to lubricate the runners. Put them up and down a few times a day and they'll recover.
It's a good idea to remove the tail lights to check for rust as there will probably be some. E28s tend to suffer from a bit of condensation in the boot.
The headlamp wash / wipe motors always gunk up. Remove them (grilles have two screws hidden on the inside behind the indicator housing) and clean everything that moves.
Carefully check fuel lines and tank for corrosion, especially where the filler pipe meets the fuel tank.
The bonnet catch can be a pain to adjust so that it opens easily but doesn't open at one corner when you over a bump. It's often down to a sticky cable in which case the best remedy is replacement of cable and sheath, BMW call it a Bowden cable.
Engines
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Four cylinder 8 valve 1.5, 1.6, 1.8 and 2.0 1961 - 1987 |
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Six cylinder 12 valve 2.0, 2.3, 2.5 and 2.7 1979 - 1991 |
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Six cylinder diesels 2.4 1983 - 1991 |
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Six cylinder 12 valve 2.5, 2.8, 3.0, 3.3, 3.4 and 3.5 1968 - 1993 |
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Six cylinder 24 valve 1978 - 1994 |
For the 518i see M10 engine problems.
For the 520i and 525e / 528e see M20 engine problems.
For the 525i, 525i, 533i and 535i see M30 engine problems.
For the M5 see S38 engine problems.
For the diesels see M21 engine problems.
One of the biggest causes of intermittent stalling on old BMWs is dying relays or dirty wiring. For peace of mind replace the aging main, fuel pump and unloader relays for 10 quid a time. Also a good idea to unplug and clean all wiring connections and body grounds. Only proper Bosch single electrode spark plugs should be used.
BMW approve unleaded only in post 6/87 cars, in practice most people run unleaded on older cars too and I've never heard of pinking or valve seat problems.
The high pressure (3.0 bar) fuel lines don't last forever. Ten years of heat and vibration will have caused cracking inside. They should be replaced with the correct BMW hose (20 quid a metre) to avoid a fire hazard, at the very least trim 10mm off the end. Don't forget the biggest culprit for fuel smells, the 6" line from the fuel rail to the cold start injector on M30 cars. Best changed by someone with small fingers and a little Vaseline on the ends of the new hose.
Poor idling can have two causes. A sticking idle control valve can be cured with white spirit and a toothbrush. Vacuum leaks are harder to find but even the small hoses, such as the one to the top of the fuel pressure regulator, can cause problems. If in doubt remove, check and clean the entire intake tract as it's not a big job.
M30s have a slightly exaggerated reputation for eating camshafts. This isn't the case unless oil changes have been neglected or the "banjo" bolts on the oil spray bar have worked lose. The head must be removed to change a bad camshaft so make sure any ticking noise isn't major expense. Remember that you need to manually adjust the valves every 30k miles so some ticking may be due to that. M30s seem to have a small oil leak from the front of the block, live with it.
M20B27 in a 525e automatic with cruise control.
M20s have a timing belt, regardless of mileage it should be changed at least every five or six years.
Overheating can cause the alloy head to warp. This may be caused by a bad viscous coupling leading to overheating in traffic. The 15 year old radiator is often the real culprit though. Non-UK cars with air conditioning use a two speed fan in front of the radiator, this can be a further cause of overheating in traffic.
If an M30 engine seems tilted forwards or out of line with the air flow meter housing suspect failing front engine mounts, not expensive.
Alternator rubber mounts fail around 130K, costs pennies and takes an hour to fix. Circlip pliers are handy. This can be the cause of squealing.
The 286bhp S38 24 valve DOHC engine is derived from the 1979-81 M1 super car and has six throttle bodies. It's very reliable indeed and is a huge tribute to Paul Rosche it's designer. Many people advise a new timing chain at 100K miles but BMW have no such policy. This is an expensive job and unless the car has a lot of track time many owners leave it unless it gets noisy.
On all of these engines you need to manually adjust the valves but on the S38 this must be done with shims.
On Motronic cars such as most Etas and the 535i a worn distributor cap and rotor arm can cause poor performance and economy as this is the only way for the computer to control the timing. If in doubt replace them.
EH automatic gearbox with S/E/1-2-3 knob.
Transmission and Drivetrain
Manual E28s normally had a five speed overdrive gearbox but the much loved five speed dog-leg close ratio box was available on larger engined cars, my M535i had one. All are very reliable. At very high mileages the shift can become sloppy, this is cured by new bushings for the linkages. Don't worry about a little noise at idle when the oil is fully warmed.
Clutches last well but hydraulics can be tricky to bleed. The clutch should feel pretty stiff but if it's VERY stiff then one of the fork arms may have snapped.
The ZF 4 HP 22 E/H automatic transmission is another story. All E28s had a four speed version and electronic control with a Sport/Economy/Manual switch next to the gear lever was optional on the Eta and standard on the 535i.
On an automatic check the fluid with the oil (Dexron III) warm and the engine running or you'll get a reading which can be way out. The fluid should be clear and not burnt. It must be changed every 30K or else. Failure to change the fluid means a new tranny around 150K miles so insist on proof. If it's not been changed for a long time then leave it. Changing it now will let all sorts of crud circulate back into the tranny and wreck it, this is why my own car is now a manual. There is also a filter screen under the tranny which should be changed every 60K, a good chance to check and clean the magnets in the drain pan too.
Never ever rev an automatic car at high rpm in park or neutral. This will cause over pressure on the A clutch pack and burn it out, time for a new trany. A pressure relief hole was added in the late 80's to reduce the problem.
Vibration under acceleration means it's time for a new centre bearing which isn't expensive. Other drive shaft vibrations can be caused by worn flex discs at either end. Post 82 cars had a more robust design.
Many cars had limited slip diffs fitted, these have an S or Z in the part number tag. Several ratios were used over the years and early cars had a different design. It's worth checking the diff mounting on early cars but to be honest the diffs are very reliable.
Brakes
All E28s except for the M5 have the same single piston front calipers, so a 518i and M535i have the same front brakes! M5s have four pot brakes. At the back the 518i and 520i had drums, the rest had discs. ABS was optional on larger engined cars from the Eta upwards and standard on the 535i / M5. The brakes aren't bad because this isn't a heavy car, it's lighter than a 635CSi which has similar brakes and they're not up to the job.
The bigger brakes from the E34 five series are a truly massive improvement. If you have an M535i and drive fast they're a bolt on upgrade and totally worth it.
Watch for vibration when braking very hard from 70mph. This can mean worn tie rods, centre tie rod, control arm bushings or warped discs.
M30 engined cars use a Citroen style hydraulic accumulator affectionately known as "the Bomb" due to it's appearance. I once had a power steering pump drive belt snap at 100mph. The residual pressure in the bomb kept the brakes working for ten times of country roads. If the bomb fails it can result in a very hard brake pedal and dangerously poor emergency stop performance.
Check the ABS light glows yellow and then goes out when the engine starts. Many owners will remove it to hide dodgy ABS (ask me how I know). ABS faults are often caused by rusting stators on the wheels. The front ones are built into the wheel bearings (45 GBP) the rear are separate (22GBP).
Seized brakes can be due to collapsed brake hoses, nothing lasts forever.
If the brake lights won't go off it's maybe not an electrical problem if it's a right hand drive car. A bad on the engine side of the firewall takes the braking force from the pedal to the master cylinder on the other side of the car, it's pivots can become dirty and stick.
Steering
Expect some play in the steering, it's just a consequence or not using a rack and pinion system. It can be adjusted out a little but if that's not enough you'll need a new steering box. Power steering isn't overdone so don't be surprised if the steering seems a little heavy.
If the steering goes hard under full lock cornering (especially when cold) it's time for a new filter in the bottom of the ATF reservoir and a fluid change.
The steering box mounts to the front subframe. The mounting isn't as strong as it could have been and has been known to crack. It can be reinforced by welding in some supports.
M535i TRX alloy, spare in my garage if you need one!
Suspension & Wheels
Rear subframe rubber bushings perish with age and cause the car to wander. Not that dear to replace but you'll need a special tool to remove the old ones.
If you lower an E28 more than 25mm the rear trailing arms will never have the correct geometry and it'll be horrid to drive. A 25mm lowering with good Bilstein shocks is the best option. A strut brace is a good idea if the suspension has been stiffened. Get the brace from Demon Tweeks.
The anti-roll bar links and rear Pitman arms (dog-bones) are cheap and easy to replace, just do it. The car will feel more planted and wander less.
Cheaper cars had 14" steel or alloy wheels. A few had the TRX style which were good in their day but expensive and outdated now, the M535i had it's own distinctive TRXs. Best idea these days is to run 16" wheels and 225/50/16 tyres all round. Wheels from any five bolt BMW fit except the E36 three series (wrong offset). New E39 five series wheels need a hub ring to fit but the offset is OK. I particularly like the 16" cross spokes from the E38 seven series but beware as those tyres are a much larger diameter.
Tyres wider than 225 front / 235 rear can cause the car to tramline, 225s are enough. If you fit 17" wheels you'd better have good steering and suspension components or the car will wander all over the place. Don't even think of using 18s.
Interior
Electric seats can fail, especially headrests. They're not normally hard to fix.
The sports seats are much nicer than the normal flavour, some of the best seats BMW ever made.
If the heater fan only works on full speed it's transistor is shot, not uncommon. The A/C has a separate fan behind the centre console. A/C adds about 50kg to the car's weight and removes the centre storage bin.
Seat mountings can crack slightly around the bolts and need welding. If your seat seems wobbly this may be why.
The back light on the onboard computer often dies, a new one just slots in from the side.
It's not uncommon for the heating to go haywire. Often it's the heater control valve showing it's age. It's easy to replace (it lives on the firewall on the engine side) but try to buy just the innards as the whole unit it 70 quid. If that's not it then check the wiring to the heater sensors in the heater core and above the driver's foot.
If the tachometer doesn't work or the service indicator lights are all screwed up it's time for repairs. Don't pay 160 quid for a new SI board, get a pair of PCB mounted NICAD batteries and solder them into the dash for a tenner. You must charge the batteries before installation. Some people use the SI lights for remote mounted radar detectors.
These cars can be converted from auto to manual. You need the box, driveshaft, flywheel, pedal box and a few other bits. I've done this and like the result. The auto is better if you only do town and motorway work and has a lovely kick down. Ask me if you want more info.
Check all the electrical goodies work, bits for these ain't cheap but they are generally reliable.