BMW 5 Series E28 525e (1983 to 1988)

The E28 was BMW's second-generation 5 Series, launched in 1981. It looked like a careful update of the E12 it replaced, but it was largely new underneath, and it ran until the E34 took over in the UK in June 1988. The 525e was the economy model of the range, introduced in Europe in 1983. The "e" stands for eta, the Greek letter engineers use for efficiency.

Before diesel was acceptable to British executive car buyers, BMW took a different route to economy. It stroked the small M20 six from the 520i to 2.7 litres, gave it a high compression ratio, a low-friction cylinder head and Bosch Motronic management, and tuned it for torque at low revs rather than power. Peak power arrives at only 4,250rpm and there is little point revving beyond 4,500rpm, but the torque is equal to the bigger 528i's and comes in much lower down. Tall gearing then lets the car cruise at very low engine speeds.

The result is a relaxed, quiet and surprisingly brisk saloon that suits an automatic gearbox, which is how UK cars were sold. Road testers, then and now, praise its refinement, smoothness and solid build. It lacks the sporting appeal of a 528i or 535i, but that tends to mean the 525e has had gentler lives. The main risks are age-related rust, tired electronics and gearboxes that have not had their fluid changed.

• Years built: 525e from 1983. E28 production ended in late 1987 (Auto Bild says October, Classics World December), and the E34 replaced it in the UK in June 1988.
• Body style: four-door saloon.
• Engine: M20 2,693cc straight six, 84mm stroke, 11:1 compression, single overhead camshaft driven by a cambelt, Bosch Motronic 1.1.
• Power and torque: 125PS without a catalytic converter, 122PS with one, and 129PS from late 1986, according to Auto Bild; torque 240Nm at 3,250rpm on the non-catalyst version. Classics World quotes 125bhp. The American 528e, its sister model, was rated lower.
• Gearboxes: a five-speed manual was standard in Germany, but UK 525e cars were automatic only, using a ZF 4HP22 four-speed with a lock-up torque converter and economy and sport modes. Some cars have the electronically controlled EH version.
• Final drive: 2.93:1, with some sources also listing 3.07:1.
• Production: Auto Bild gives 683,924 E28s of all types. Motor1 Germany gives about 40,621 525e cars for Europe and 89,853 528e cars for the USA and Japan. Treat these as approximate.

• 1981: E28 launched in 518, 520i, 525i and 528i form. The US 528e, which used the same idea, arrived first; Motor1 dates it to autumn 1981, BMWBlog to 1983.
• Spring 1983: 525e launched in Germany. Getrag manual gearboxes had been phased in from late 1982.
• March 1984: catalyst version of the 525e.
• September 1984: facelift with a deeper front valance and wider tyres. Early E28 automatics were three-speed ZF units, but the UK 525e was tested with the four-speed 4HP22.
• Late 1986: Lux versions arrived in the UK, and the 525e gained power.
• 1987: final full year of production.

Bodywork and structure

Check the leading edge of the bonnet, front wings, suspension turrets, sills and jacking points, and the A-posts and door seal areas. Front footwell floors rot from wheel spray, and rear damper towers and the floor under the rear seat are also vulnerable. Blocked drains rot the door bottoms and rear of the sills, and leaking sunroof drains put water into the footwells. Look at the double-skinned mounting points for the rear axle beam, the tail lamp areas and the boot for damp. The fuel tank can corrode around the filler neck. Watch out for poor past welding.

Engine

The cambelt and tensioner need renewing at about 30,000 miles or every few years whatever the mileage, ideally with the water pump and cam seal. Ask for written proof of when it was done. Overheating can warp or crack the alloy head, so check the coolant for oil, look at the radiator and viscous fan coupling, and ask about annual coolant changes. A sharp "chuffing" exhaust note means a cracked manifold or broken studs. Intermittent non-starting or stalling usually points to the fuel pump or main relays, or to one of the two crankshaft position sensors. Spare Motronic control units are scarce. A rough idle often comes from a sticking idle valve or small vacuum leaks.

Gearbox and drivetrain

Ask for proof of automatic fluid changes, roughly every 30,000 miles. A neglected box may fail around 150,000 miles. With the engine running and warm, the fluid should be clear and not smell burnt. Never let anyone rev the engine hard in Park or Neutral, as that can burn out the forward clutch. On EH gearboxes most faults trace back to damp control units and corroded connections. Vibration when accelerating usually points to the propshaft centre bearing or flexible couplings.

Suspension, steering and brakes

A wobble around 55mph or shake under braking is usually worn front upper control arm bushes, though sticking calipers can cause it too. Check the front strut lower spring cups for rot, and listen for knocks from the rear subframe and beam bushes, which make the car wander. Some play in the steering box is normal, but the box mounting can crack. Brake hoses can collapse internally and make brakes stick. If ABS is fitted, the warning lamp should light and then go out; rusty sensor rings are the usual fault.

Electrics and interior

Leaking batteries on the instrument circuit board can damage the instruments and the service indicator. A heater fan that works only on full speed usually needs a new resistor or transistor. Check the electric windows, seats, check panel and on-board computer if fitted. Look for cracked dashboard tops, worn driver's seat bolsters and shrunken door trim fabric.

Identity and paperwork

Check the VIN on the V5C against the car and confirm the engine is the eta unit. A 1987 car does not qualify for the historic tax class, which requires a build date before 1 January 1986. It will become eligible for MOT exemption only when it is more than 40 years since it was built or first registered, so for now it still needs an annual MOT. Check the MOT history online.

Service parts are generally easy to get, as the M20 was used widely, but body panels can be expensive and good dashboards, seats and Motronic units are getting scarce. Independent BMW specialists familiar with older models can do most work. The main UK club is the BMW Car Club of Great Britain, founded in 1952, whose website is given as bmwcarclubgb.uk (opens in a new tab).

• When were the cambelt, tensioner and water pump last changed, and is there an invoice?
• Has the automatic gearbox fluid been changed regularly, and is it the EH version?
• Has the car ever overheated or had a cylinder head replaced?
• What rust repairs have been done to the front footwells, sills, turrets and rear axle mountings?
• Do all the instruments, the service indicator and the electric equipment work?