BMW 540i
Large-displacement V8 with effortless power delivery. Timing chains and their guide rails are the main weakness; replacement is labour-intensive and expensive.
V8 Gentleman
4.4-litre NA V8 — relentless pull, sonically in a class of its own.
Engine Weaknesses 7
The timing chain and plastic guide rails on the V8 wear at high mileage. Replacement of all timing chain components is recommended from around 150,000 km.
Symptoms: Rattling on cold start, rough engine running, risk of engine damage at advanced wear.
The V-deflector rail and guide rails on the M62B44 V8 break from around 180,000–200,000 km. The timing chain knocks against the housing causing rattling and whining.
Symptoms: Whining sound similar to a failing alternator, cold-start rattling, wear marks on the inside of the chain housing
The O-rings in the VANOS system harden and shrink. Pressure loss leads to inaccurate camshaft phasing and power loss in the lower rev range.
Symptoms: Rough idle, power loss in the lower rev range, increased fuel consumption.
The M62B44 VANOS solenoid valves leak or become fouled with age. Camshaft phasing fails or operates imprecisely.
Symptoms: Engine warning light with VANOS fault code, rough running between 1,500–2,500 rpm, power loss especially when accelerating from low revs
The M62B44 water pump as well as the expansion tank and intake manifold gaskets lose coolant at high mileage. The V8 is very sensitive to overheating.
Symptoms: Coolant level drops without visible puddle, overtemperature warning under full load, coolant stain at intake manifold gasket area
The valve stem seals on the M62B44 wear at high mileage, especially when the engine has had extended periods of standing. Oil is drawn through the valve guides into the combustion chamber.
Symptoms: Blue smoke on cold start or after extended idling, increased oil consumption without visible external leaks, blue deposits on spark plugs
Both cam cover gaskets on the V8 become porous and leak. Oil drips onto hot exhaust components and produces smoke. A typical maintenance item at higher mileages.
Symptoms: Oil smoke from the engine bay when hot, oil smell inside the cabin through the ventilation, oil spots under the vehicle.
Vehicle Weaknesses 7
Water enters through porous door seals, collects in the sills, and can't drain. Rust forms from inside; jacking points collapse. Structurally safety-critical.
Thermostat housings, coolant pipes, and the expansion tank become brittle with age. A crack on the motorway leads to overheating within minutes.
The plastic impeller detaches from the pump shaft without the pump appearing visibly faulty. Coolant stops circulating and overheating follows quickly.
Diesel models are fitted with the GM automatic gearbox, which is significantly more failure-prone than its ZF counterpart. Shift delays and overheating often lead to total failure.
Rear integral arms wear regularly. When the ball joint is worn out the rear wheel loses lateral support. Typical problem over 100,000 km.
The steering rack develops leaks on older examples almost as a rule. Power steering fluid drips from the seals; steering feels sluggish or makes noise when turning.
The butyl tape behind the door membranes ages and lets water into the cabin. Rear footwells and the Touring boot are particularly affected. Mould and electrical damage can follow.