BMW 850 and 840 (1991 - 1999) Fault Guide

Evolutions

Year Change or development
1991 850 and 840 launched in UK
1993 840 Ci (286 bhp) and 850 CSi (380 bhp) launched with uprated suspension. Revisions: airbag; 12-speaker audio system.
1994 All models have passenger airbag.
1995 840 Ci now has Servotronic power steering.
1996 840 Ci now has 4398cc 286 bhp engine.
1997 840 Ci Sport: M-Sport suspension, front spoiler, sports seats.

Bodywork and External Checks

Area What to look for What it means What to do
Corrosion Inspect the car carefully for corrosion. The earlier cars are beginning to show minor signs of rust. The rust needs to be cut out and the bodywork made good. Negotiate a £100 discount per spot of rust.

Engine Checks

Area What to look for What it means What to do
V8 engines Leave the engine on and listen for the engine misfiring (rather than the revs being constant when on idle and the engine making a consistent noise, it splutters and spits). Drive the car to see if the running remains lumpy and poor. Poor running and misfiring, on earlier V8 engines in particular, can indicate that the Nikasil engine block is suffering bore wear. The engine will need rebuilding if that is the case with new pistons and a new block. Negotiate a £2,500 discount or have the repair completed.
V12 engines Start the engine from cold with the bonnet open. Listen for a ticking noise at the top of the engine. The ticking means the hydraulic lifters are in need of repair. Negotiate a £400 discount or have the repair completed.
Exhausts When the engine is cold listen for rattles from the exhaust. This is an early warning sign that the exhaust and catalytic converter are going to fail. Negotiate a £465 discount for each of the two 'cats' or have the repair completed. Total exhaust cost: £2,000.

Interior Checks

Area What to look for What it means What to do
Gearbox Test-drive the car and see if it accelerates smoothly or delays when you press the accelerator and then surges forward. The gear change will also feel clunky. The automatic clutch is slipping so the gearbox will need a rebuild. Negotiate £1550 price reduction or have the repair completed.
Displays Check that the digital displays work. If the display is breaking up or hard to read it needs replacing. Negotiate a £250 discount or have the repair completed.
Steering When driving on a good flat road, check that the car holds a straight line easily and doesn’t wander to the side of the road. Then turn the wheel from side to side to test how precise the steering is. It should be firm and decisive, not vague and woolly. If the car wanders or the steering is vague, the problem is usually the power assisted steering box. Negotiate a £1000 discount or have the repair completed.

Wheels, Brakes and Suspension Checks

Area What to look for What it means What to do
Shock absorbers Look up inside the wheel arch at the suspension springs. Inspect the spring and leg for grease, wetness or oil weeping out. The shock absorbers or self-levelling dampers are leaking and need to be replaced. Negotiate a £500 discount per side or the repair completed.
Ball joints As you drive the car over rough surfaces or bumps (e.g. speed bumps) listen for a knocking noise coming from the suspension. A knocking noise from the suspension usually indicates that a ball joint or bush needs replacing. Negotiate a £600 discount or have the repair completed.
Brake pipes Look under the car for metal pipes that run almost the complete length of the vehicle. Check that there is no rust on these pipes. These are the brake pipes and need to be replaced if rusty. Negotiate a £300 discount or have the repair completed.

Recalls

Date Model Recall
19 Mar 1999 Built before: 30/11/1994 Overloading may occur in the coolant circuit which encompasses the engine, radiator and heat exchanger. Should the heat exchanger be affected, hot water and steam may suddenly escape into the vehicle interior. This could seriously impair visibility through the windscreen. Injuries to the feet and lower legs may also result.

Recommended Garages

Name Phone Address Website
MOT ANGEL (Nationwide) 0800 131 0030 3 The Minster, Portman Road, Reading, RG30 1EA. http://www.motangel.co.uk