Mercedes-Benz E 55 AMG Kompressor
5.4-litre V8 with Eaton Lysholm twin-screw supercharger — the legendary 'Kompressor' AMG. 476–500 hp depending on model, 700+ Nm from 2,650 rpm. The sound is unmistakable: a deep V8 rumble overlaid with the characteristic supercharger whine under load — at full throttle a mechanical scream that's instantly addictive. Torque arrives like a wave: gently swelling then brutal. No turbo lag, no throttle delay — the supercharger delivers boost from idle. Tuning potential is enormous: a pulley swap (83 mm instead of 87 mm) adds 40–50 hp at the rear wheels, and the community has pushed the engine beyond 800+ hp. Critical maintenance points: supercharger magnetic clutch (check air gap 0.35–0.45 mm), charge air cooler pump (low-temperature circuit), rear crankshaft seal. Oil changes with 0W-40 every 10,000 km. Pre-2004 engines had more teething problems — noticeably more mature from 2004. One of the most robust AMG engines ever built when maintained properly.
Family + Madness — 476 hp Estate with 1,950-Litre Boot
The most extreme sleeper concept in the M113K lineup: pram and bicycle in the boot, overtaking sports cars on the motorway. 4.8 seconds to 100, Brembo 8-piston front brakes, Airmatic standard. Technically identical to the saloon; the estate body gives a slightly different resonance — more damped. Rarer than the saloon, rising collector value. 20–22 L/100 km in town is the price for the family madness.
Engine Weaknesses 9
The Eaton supercharger bearings wear after 100,000+ km — mechanical noise increases, in worst case the supercharger seizes. Check supercharger oil (120–130 ml) regularly. Replacement supercharger from 1,200 EUR, complete with installation 2,500–3,500 EUR.
Symptoms: Increasing mechanical whining/howling from the supercharger even at low rpm, metallic grinding under load, supercharger oil loss.
Coolant hoses become brittle after 10+ years and can burst without warning — particularly critical on a supercharged V8 with high heat rejection. Thermostat occasionally sticks open. Complete coolant hose set as prevention from 60,000 km recommended.
Symptoms: Coolant temperature rises above 100°C, coolant steam under the bonnet, coolant loss, sweet smell from vents.
The Eaton supercharger magnetic clutch wears over time — friction material wears, supercharger sporadically fails to engage. Air gap (clearance) must be 0.35–0.45 mm; above 0.8 mm the clutch no longer engages reliably. Aftermarket pulley modifications worsen the problem if air gap is not correctly set.
Symptoms: Sporadic power loss at full throttle, supercharger does not engage (no supercharger whine audible), EPC fault message in instrument cluster, releasing and re-applying throttle helps briefly.
The separate low-temperature coolant pump for the charge air cooler fails — charge air temperature rises, engine loses noticeable power under sustained load. No engine damage, but frustrating power loss especially in summer and on motorways.
Symptoms: Creeping power loss with warm engine under sustained load, charge air temperature rises above 60°C (visible on scan tool), no fault message — only subjectively less power.
The rear crankshaft seal becomes leaky over time — oil drips onto the gearbox flange. Repair requires gearbox removal, hence high labour cost. Best combined with another gearbox service.
Symptoms: Oil spot under the vehicle at the bell housing, visible oil film at the engine/gearbox interface, slightly rising oil consumption.
The OEM crankshaft pulley has a rubber damper that detaches after 80,000+ km — belt jumps, engine stops. Aftermarket steel/aluminium pulleys (e.g. Fluidampr, NS Custom) as a permanent solution. Due anyway with a pulley modification.
Symptoms: Squeaking noises from the belt drive, visible belt misalignment at the crankshaft pulley, pulley wobbles on visual check.
Rubber engine mounts wear faster than on the naturally-aspirated M113 due to the higher torque (700+ Nm). Torn mounts cause noticeable vibrations at idle and stress the driveshafts and gearbox. Preventive replacement every 60,000–80,000 km.
Symptoms: Vibrations at idle felt at steering wheel and gear lever, dull thudding on throttle on/off, engine visibly moves when revving.
The 8 ignition coils and ignition leads age faster than on the naturally-aspirated M113 due to the higher thermal load of the supercharged engine. Balance deviations >3.5 per cylinder indicate ignition problems. Replace all 8 at the same time; Bosch quality recommended.
Symptoms: Rough idle, cylinder balance deviation >3.5 on balance test, misfire fault codes P0300–P0308, slight hesitation at part throttle.
Various vacuum hoses and the fuel tank vent hose become brittle and fall off — false air causes rough idle and hesitant pull-away. Often overlooked because symptoms are subtle and the engine runs normally under load.
Symptoms: Hesitant pull-away below 1,500 rpm, rough idle after warm-up, hissing from engine bay at idle, sporadic power fluctuations.
Vehicle Weaknesses 7
Sensotronic Brake Control on pre-facelift models (2002–2006) suffered hydraulic failure. Approximately 1.3 million vehicles were recalled worldwide. Repair cost €2,200–3,500.
Airmatic air suspension fails due to compressor failure and defective air reservoirs. Replacement is only possible with the rear axle removed.
The Signal Acquisition and Actuation Module (SAM) fails, particularly when water ingress occurs. Leads to loss of lighting, windscreen wipers and instrument cluster.
SBC electrohydraulic brake (2002–2006) suffered from faulty high-pressure pump control. Two recalls in 2004 and 2005. SBC vehicles require specialist workshop.
AIRMATIC air suspension wears heavily. Air reservoir and compressor fail frequently. Replacement requires complete rear axle disassembly — very costly.
Control arm and track rod end bearings develop play. A common MOT failure point. Regular cause for failed MOT inspection.
SAM modules (front and rear) control lighting, wipers and door functions. Moisture damage and ageing lead to complete failures.