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BMW E30 Three 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 Six isn't as bad as the 2002, worth a check though. I'd also remove the rear seats (two bolts below front lip) 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. E30 doors aren't as bad as E24/E28 doors.

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.

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 buy generally E30s aren't too bad here. Unlike some other 80's BMWs the boot should be bone dry. It's not uncommon for the rear valance to rust a little and this can make a hole into the side pockets on the boot floor.

Headlamp wash / wipe motors always gunk up. Remove them and clean everything that moves.

The hydraulic headlight aim height adjusters never work. I had a three year old 318iS with 5000 miles and they didn't work on it.

Carefully check fuel lines and tank for corrosion. E30 tanks are metal and they tend to rust half way up where the filler pipe joins. If buying an E30 used it's worth filling it with petrol to check for leaks. To fit a new tank you need to drop the driveshaft and exhaust so it's a pain.

E30s are one of the few BMWs where the bonnet catch mechanism still works properly after 20 years!

Check the sill jacking points as using them with the factory jack often breaks the underseal and lets rust start.

BMW E30 rust

Classic rust spot at base of A pillars.

Check the area where the bottom corners of the windscreen meet the scuttle and wings (fenders) for rust, common spot.

If the car has a silly rear spoiler it'll be too heavy for the boot struts to support it when open.

Cars with chrome arch lips are using them to hide rust.

If a two door car has hinge opening rear windows that leak or whistle at speed try some rubber restorer. Let loads of it soak in with the windows open to let the rubber puff up a bit. As a bodge to stop leaks use loads of Vaseline.

Remove the rubber strip under the rear window on tourings to check for rust.

If the wipers judder on intermittent it's because the grease in the gearbox on the end of the motor has dried out or the disc that's in there is very rusty. You might get away with using new grease of making a new electrical contact disc from a can lid! If not it's new motor time.

Central locking faults can sometimes be traced to rust in the connectors between the door and body. In severe cases this can cause a short circuit which is verging on a fire hazard.

It's not uncommon for the metal link between the boot's central locking solenoid and lock to fall off at one end.


M10 (chrome bumper cars)

Four cylinder 8 valve

1.5, 1.6, 1.8 and 2.0

1961 - 1987


Six cylinder 12 valve

2.0, 2.3, 2.5 and 2.7

1979 - 1991


Six cylinder diesels


1983 - 1991

M30 (South African 333i)

Six cylinder 12 valve

2.5, 2.8, 3.0, 3.3, 3.4 and 3.5

1968 - 1993

BMW m40 engine

M40 (plastic bumper cars)

Four cylinder 8 valve

1.6, 1.8 and 1.9

1988 - 2001

BMW m42 engine


Four cylinder 16 valve

1.8 and 1.9

1989 - 1998

BMW s14 engine


Four cylinder 16 valve

1986 - 1991

For the chrome bumper 316 and 318i see M10 engine problems.

For the plastic bumper 316i and 318i see M40 engine problems.

For the 318iS and US 318i see M42 engine problems.

For the 320i, 325e and 325i see M20 engine problems.

For the 333i see M30 engine problems.

For the M3 see S14 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 (twin electrode NGK for M42).

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. On the M40 and M42 there are two one inch lines under the intake manifold, you need to remove the top half of the manifold to see them but it's not a big job.

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. The vacuum lines on the M40 and M42 weren't made from a fantastic grade of rubber, it's worth removing the top half of the intake manifold (easy) and examining it all.

On the M20, M40 and M30 it's vital the distributor cap and rotor arm are in good condition as this is the only way Motronic can control the timing. Lack of power at high rpm or poor economy can be the symptoms.

BMW E30 Engine bay

Engine bay from a four cylinder right hand drive manual car.

M20s and M40s have a timing belt, regardless of mileage it should be changed at least every five or six years. It's not that bad a job although access it tight on the M20, removing the radiator helps a lot.

Overheating can cause the alloy head to warp. This may be caused by a bad viscous coupling leading to overheating in traffic. An old radiator is often the real culprit though.

Oil leaks on the M42 and M40 are often due to stripped threads on the rocker cover caused by overtightening.

Chain noise on a cold M42 can often be cured by a new tensioner, if you ignore it it'll get worse. Very easy to fit.

The M20 has a pretty basic exhaust manifold, nice tubular headers can make a big difference. The M42 has a much nicer set.

Cooling systems on these engines are much better than on modern BMWs but still need a fluid change every two years.

If you have a Pierburg carburettor on a 316 throw it away and replace it with a nice new Weber.

Sticky tappets on an M40 or M42 may respond well to an oil flush before your next oil change.

If your M40 ticks like an annoying sewing machine don't worry, they all do.

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.

On the M10, M20 and M30 engines you need to manually adjust the valves every 30k miles. On the S14 this must be done with shims.

Transmission and Drivetrain

Manual E30s normally had a five speed overdrive gearbox but the five speed dog-leg close ratio box was available on M20 cars as an option. I've seen it on 320i's and 323i's but never on a post-facelift car. 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.

A noise when the clutch pedal is pressed can be a bad release bearing. But on a warm car some noise is normal, even on very low mileage cars.

The M42 and M40 could suffer from hot clutch shudder after extended periods of spirited driving. I've seen it three time on my last 318iS. It's caused by the use of non-asbestos clutch linings and even a newish clutch can do it.

The four speed ZF 4HP22 automatic transmission was used on almost all E30s although some early cars were three speed. The EH (electro-hydraulic) version with electronic control and a Sport/Economy/Manual switch next to the gear lever was optional on the 325i. On non-EH cars a mechanical kickdown linkage is connected to the throttle body.

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. There is 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.

You really want a manual.

Driveshaft centre bearings can fail but it's not that common. When mine went it make a strange knocking sound under hard cornering.

Some cars had limited slip diffs fitted, these have an S or Z in the part number tag.

Don't assume a noise from the back is a bad differential. I bought a cheap 318iS with a "bad diff" that was fixed by two new rear wheel bearings.

BMW E30 abs brakes

ABS valve pack and a badly mounted cone filter.


E30's don't have the best brakes in the world. For this reason you need to fit decent quality pads and discs. You also need to change the fluid every two years.

The fact that almost all E30s have four bolt hubs (except the M3 and some South African cars) means there's no easy upgrade path for the brakes. This sucks hugely. You can fit five bolt hubs using Z3 / E36 Compact parts but it's a hassle and you'll need new wheels.

If you have rear drums you can convert to discs but don't expect a massive improvement as the drums aren't bad and the discs aren't that big.

If the brakes seem to need a lot of force to work check the non-return valve on the vacuum line that runs from the intake manifold to the servo.

It you hear a rubbing from the back it may be that the brake backing plate has rusted and the pin holding the brake shoes in place has popped out. This allows the handbrake shoes to rub on the disc's inner drum.

If laying up a car for the winter leave the handbrake off or the shoes will stick to the brake disc.

Watch for vibration when braking very hard. This can mean worn tie rods but it more likely to be lower control arm bushings or warped discs. If fitting new bushings use harder polyurethane ones.

Check the ABS light glows yellow and then goes out when the engine starts. Many owners will remove it to hide dodgy ABS. 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.

Right hand drive E30s still have the master cylinder on the left. It's connected by a bar running from one side to the other but unlike the E24/E28 it's inside the cabin so doesn't gum up.


E30 steering should be direct and free from play. If it's not the rack is worn or you have badly worn tie rods.

Early E30s didn't have power steering. Some say removing the power steering buy taking off the drive belt gives the car more feel but personally I don't see the need.

If the steering goes hard under full lock (especially when cold) it's time for a fluid change. If it's bad you may need to remove the reservoir and try to clean it (good luck). Prevention is better than cure, change the fluid.

E30 steering has too many turns lock to lock, this is compounded by overly large steering wheel designs. This was done as they didn't all have power assistance in the beginning. You'll get used to it. If you don't you can fit E36 parts. M3s have a quicker rack but only in left hand drive.

BMW E30 16 inch Alpina alloy wheel

Rare 16 inch Alpina alloy, the locking cap means it's not a fake.

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 E30 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. The //M-Tech suspension is about 15mm lower than stock. Please don't fit coil overs, it's not the right thing.

E30s are stiffer and smaller than E24/E28s and I don't really see the need for a strut brace on a road car unless it's a touring or cabriolet.

The anti-roll bar links are cheap and easy to replace, just do it. The car will feel more planted and wander less.

Fitting poly lower control arm bushings helps feel under braking and is a great idea. Solid bushings from the M3 fit and give an offset increasing the camber and track.

The largest factory anti-roll bar was 14.5mm. Anything larger can snap the mounting points on the trailing arms so you need to reinforce them. Poly bushings on the anti-roll bars are a great idea.

Cheaper cars had 14" steel or alloy wheels. 15" cross spokes were perhaps the most common upgrade and look great, they wear 205/55/15 tyres. 16" wheels were available from the usual suspects such as Alpina, Hartge and AC Schnitzer - these are worth a ton on money now. 15s are all you need and they work well. Please don't fit 17s, they look wrong and kill the ride quality without gaining anything.

BMW E30 Interior from Motorsport Design Edition cabriolet

Interior from Motorsport Design Edition cabriolet.


The sports seats are much nicer than the normal flavour, some of the best seats BMW ever made.

The back light on the onboard computer often dies, a new one just slots in from the side.

If the tachometer doesn't work or the service indicator lights are all screwed up it's time for repairs. It's possible to replace the batteries rather than buy a new SI board. I think early cars may have used NICADs (charge before installing them) but my '90 had a smaller pair which from memory were some type of lithium battery.

Check all the electrical goodies work, bits for these ain't cheap but they are generally reliable.

Very little goes wrong with E30 interiors. They're much more solidly built than those on earlier BMWs.