BMW E36 3 SERIES – 10 MOST COMMON MOT FAILS

BMW E36 3 SERIES – 10 MOST COMMON MOT FAILS

Posted by Glenn Rowswell on 2nd August 2018

Putting any car in for a MoT can be a daunting experience but a quick check before turning up at the garage can often mean the difference between a pass and a fail. Here we look at the main reasons for MoT failure for the BMW E36 3 Series…

The BMW E36 is now an old car, with the very last convertible and estate versions being built in 1999 and the final compacts in 2000. The oldest ones were built in 1991 and they’re all old enough to cause headaches at MoT time.

However, parts are cheap and they are still quite easy to work on, often easier than the previous E30 model, as well as the E46 that replaced it.

Rust, brakes pulling to one side or the other, emissions, corroded brake pipes and worn suspension components are all common to older cars like these, but listed below are the ten most common MoT dramas for the E36.

MOT FAILS BMW E36 3 SERIES

1. EMISSIONS: Virtually all E36’s are now subject to an emissions test, although pre-August 1992 cars (H and J plate) can avoid this and even cars up to 1995 can scrape though a BET (basic emissions test). Later ones can still fail and all E36’s have catalytic converters. Only original BMW ones are any good and the cheap ‘Euro Cats are generally very flaky. A good used original will still work after 20 years.

MOT FAILS BMW E36 3 SERIES

2. RUST: Whilst E36’s were less rot prone than the E30, they are all old enough to be in trouble. The sills rot out – the E36 had a smooth underside with the sill seams flat against the floor but the rear sills rot, and rust strikes around the circular lifting pads underneath. The rear trailing arm mounts can rust away behind the bush mounting bracket, whilst front anti roll bar mounts can rust merrily away largely unseen.

MOT FAILS BMW E36 3 SERIES

3. BRAKE PIPES: E36 brake pipes rust like any other. The rear ones are the worst and they need to be routed over the fuel tank – drop one side at a time and it’s not too bad. Pre-1998 cars used rear metal pipes with two short flexies and an ‘S’-shaped pipe but you can replace that with the later E46 type long single flexible hose. The front ones run behind the engine and are a pig to change. Use a Draper hand held flaring tool and splice a new pipe in under the wheel arch.

MOT FAILS BMW E36 3 SERIES

4. ABS: Most E36’s have standard ABS except the early 316i and 318i models until 1992/3. There are two systems – the type used on pre 1995 fours and all sixes with the ABS block in the rear right of the engine compartment. These cars also have the ABS ECU behind the glovebox, and later fours hve a combined ABS block and ECU under the battery. Faults are worn sensors, faulty ECU’s and occasionally expanding rust behind the stainless ABS trigger rings on the CV joints.

MOT FAILS BMW E36 3 SERIES

5. REAR TRAILING ARM BUSHES: These rubber-bonded bushes at each end of the trailing arm wear out and delaminate, resulting in movement and clonking. Fitting new ones is okay as long as the 18mm bracket bolts comes out and the metal behind isn’t rotten – many are. Compacts use the E30 type semi-trailing arm suspension and the axle beam bushes wear out. Unlike the E36 trailing arm bushes, you will definitely need the special tool to replace these.

MOT FAILS BMW E36 3 SERIES

6. DAMPERS: E36 front dampers will eventually leak but like most, they will be finished long before then. Fluid leaks are laughably called ‘misting’ on the MoT sheet and that means past there sell-by date. If the bump stop is falling to bits, then the dampers will be ruined and anything rusty and tatty will be worn out. New ones – even a good budget brand like Anschler – will give a huge improvement.

MOT FAILS BMW E36 3 SERIES

7. BROKEN REAR COIL SPRINGS: This has been a common BMW fault on just about every 3 Series built. They are simple to change – unbolt the damper and with a long bar between the hub and the upper arm, force the suspension down and wriggle the spring out. You’ll need both rear wheels off the ground though to avoid the rear anti roll bar (except the 316i) counteracting it.

MOT FAILS BMW E36 3 SERIES

8: HEADLIGHTS: Headlight condensation has always been an E36 bogey and there’s not a massive amount you can do about it, although removal (four 8mm bolts), a good clean up and dry out and new seals will go a long way to helping. Severe condensation will affect the beam pattern. Get the adjusters working as well, as they will normally need to be adjusted at MoT time.

MOT FAILS BMW E36 3 SERIES

9. AIRBAG LIGHT: All E36’s after December 1994 had a standard airbag containing inside the three spoke steering wheel with SRS on the bottom spoke. They don’t give a lot of trouble but the light will come on if the wheel has been removed – even with the battery disconnected. Diagnostics can reset this though. Pre-1995 cars often came with a dealer fit accessory airbag wheel with a red light in the lower spoke – the control unit is inside the steering wheel. Replace with a standard wheel if you can’t resolve this issue in time for the test.

MOT FAILS BMW E36 3 SERIES

10. OUTER FRONT BALLJOINTS: The E36 used E30 style forged steel lower wishbones but with a rubber sleeved outer balljoint. These both work loose (it won’t pull out, so don’t worry) and will just develop play. It’s best to replace the complete arm when it comes time to replace a balljoint. If you have the special tool, you can replace the balljoint and you can fit solid E30-style joints (standard E30 ones don’t fit – they’re too small) but a pair of brand new arms isn’t that expensive and saves the hassle of swapping the joints.