The following torque figures have been gathered through work we have undertaken on all smart models. This list is not exhaustive and has been based on record information made available to us. These figures are subject to change and should be used with care.
| Pistons / Crank | Applicable Models | Torque |
|---|---|---|
| Piston conrod bolts (2x per piston) | All 450, 451 & 452 engines | 15Nm + 90° |
| Piston conrod bolts (2x per piston) | CDI | 5Nm + 25Nm + 180° |
| Lower crankcase bolts (8x M8) | All 450 & 452 | 21Nm + 90° |
| Lower crankcase bolts (8x M8) | CDI | 55Nm + 90° |
| Lower crankcase bolts (13x M6) | All 450 & 452 | 9.5Nm |
| Oil Pump System | Applicable Models | Torque |
| Oil pump sprocket (1x) | All 450 & 452 | 20Nm |
| Oil pump bolts (3x) - Initial Torque Oil pump bolts (3x) - Final Torque |
All 450 & 452 | 12Nm 9.5Nm |
| Oil pick up pipe bolts (3x) - Initial Torque Oil pick up pipe bolts (3x) - Final Torque |
All 450 & 452 | 14Nm 9.5Nm |
| Oil baffle bolts | All 451 | 24Nm |
| Oil filter body bolts - blind hole (3x) | All 450 & 452 | 12Nm |
| Oil filter body bolts - through hole (2x) | All 450 & 452 | 9.5Nm |
| Oil filter case | All 450 & 452 | 23Nm |
| Oil cooler water line to crankcase (2x) - initial torque Oil cooler water line to crankcase (2x) - retightening torque |
450 Brabus (55kW) & 452 | 12Nm 9.5Nm |
| Timing chain oil sprayer to crankcase (1x) | All 450 & 452 | 20Nm |
| Piston oil sprayer (1x per cylinder) | All 450 & 452 | 20Nm |
| Oil plug to crankcase (accessed behind clutch) | All 450 & 452 | 30Nm |
| Engine Timing | Applicable Models | Torque |
| Timing chain tensioner bolts (2x) | All 450 & 452 + 450 CDI | 12Nm |
| Timing case oil duct bolt (1x) | All 450 & 452 | 30Nm |
| Timing case bolts - Initial Torque Timing case bolts - Final Torque |
All 450 & 452 | 12Nm 9.5Nm |
| Timing case bolts M6 | All 451 | 10Nm |
| Timing case bolts M8 | All 451 | 23Nm |
| Bolt connecting end of crank sealing ring to crankcase | All 451 | 10Nm |
| Timing case plug | All 451 | 50Nm |
| Drive plate / Pulleys | Applicable Models | Torque |
| Belt pulley bolt into crankshaft (1x) | All 450 & 452 + CDI | 140Nm + 90° |
| Bolt holding drive plate to clutch end of crankshaft (6x) | 450 599cc engines only | 47.5Nm + 90° |
| Bolt holding drive plate to clutch end of crankshaft (6x) | All 698cc engines only + CDI | 45Nm + 90° |
| Clutch and Gearbox | Applicable Models | Torque |
| Clutch module to drive plate bolts (3x) | All 450 & 452 | 20Nm + 90° + 10° |
| Clutch pressure plate to flywheel bolts | All 451 | 20Nm |
| Clutch release bearing to gearbox (2x) | All 450, 451 & 452 | 10Nm |
| Clutch actuator bolts (3x) | All 450, 451 & 452 | 10Nm |
| Gearbox bolts (gearbox to engine 2x) | All 450 & 452 | 23Nm |
| Gearbox bolts (gearbox to engine) | All 451 | 45Nm |
| Gearbox oil fill and drain plugs (2x) | All 450, 451 & 452 | 43Nm |
| Gearbox assembly bolts | All 450 & 452 | 27Nm + release + 25Nm |
| Cylinder Head | Applicable Models | Torque |
| Cylinder head bolts (8x) | All 450 & 452 | 21Nm + 90° + 90° + 10° |
| Cylinder head bolts (8x) | CDI | 30Nm + 90° + 90° + 90° + 10° |
| Cylinder head bolts | All 451 | 25Nm + 90°+ 90° |
| Cylinder head bolt to timing cover (2x) | All 450 & 452 | 27Nm |
| Sump | Applicable Models | Torque |
| Sump bolts (14x) - Initial Torque Sump bolts (14x) - Final Torque |
All 450 & 452 | 12Nm 9Nm |
| Sump bolts - Initial Torque Sump bolts - Final Torque |
All 451 | 10Nm 10Nm |
| Dipstick tube bolt (1x) - Initial Torque Dipstick tube bolt (1x) - Final Torque |
All 450 & 452 | 12Nm 9Nm |
| Sump drain plug | All 451 | 65Nm |
| Cam Shaft | Applicable Models | Torque |
| Camshaft sprocket bolt (1x) | All 450 & 452 | 21Nm + 90°+ 10° |
| Camshaft cap bolt (2x per cap) - Initial Torque Camshaft cap bolt (2x per cap) - Final Torque |
450 599cc engines only | 11Nm 8.4Nm |
| Camshaft cap bolt (2x per cap) - Initial Torque Camshaft cap bolt (2x per cap) - Final Torque |
All 698cc engines | 12Nm 12Nm |
| Rocker Cover | Applicable Models | Torque |
| Rocker cover bolts (6x for 599c or 5x for 698cc) - Initial Torque Rocker cover bolts (6x for 599c or 5x for 698cc) - Final Torque |
All 450 & 452 | 12Nm 9.5Nm |
|
Rocker cover breather channel plate bolts (2x) - Initial Torque Rocker cover breather channel plate bolts (2x) - Final Torque |
All 450 & 452 |
12Nm 9.5Nm |
| Rocker cover bolts | All 451 | 10Nm |
| Load bleed plate to crankcase bolts | All 451 | 10Nm |
| Ignition Coils | Applicable Models | Torque |
| Coil pack bolts (2x per coil pack) | All 450 & 452 | 14Nm |
| Coil pack bolts (2x per coil pack) | All 451 | 10Nm |
| Starter Motor | Applicable Models | Torque |
| Starter motor bolts (2x) | All 450 & 452 | 23Nm |
| Starter motor bolts | All 451 | 42Nm |
| Constant live connection to starter motor (1x) | All 450 & 452 | 8Nm |
| Constant live connection to starter motor | All 451 | 10Nm |
| Water pump system | Applicable Models | Torque |
| Water pump to carrier bolts (7x) | All 450 & 452 | 9.5Nm |
| Water pump carrier to crankcase bolt (4x) | All 450 & 452 | 20Nm |
| Water pump pulley to water pump (4x) | All 450, 451 & 452 | 10Nm |
| Turbo water pipes banjo bolts | All 450 only | 19Nm |
| Turbo water pipes banjo bolts | All 452 only | 20Nm |
| Thermostat to cylinder head (2x) - initial torque Thermostat to cylinder head (2x) - final torque |
All 450 & 452 | 12Nm 9.5Nm |
| Water supply connection to carrier (2x) - initial torque Water supply connection to carrier (2x) - final torque |
All 450 & 452 | 14Nm 9.5Nm |
| Water pump to timing case - M6 | All 451 | 10Nm |
| Water pump to timing case - M8 | All 451 | 23Nm |
| Thermostat housing bolts | All 451 | 10Nm |
| Coolant pipe bolts (crankcase & oiil pan) | All 451 | 10Nm |
| Coolant Drain Plug | All 450 & 452 | 12Nm |
| Inlets | Applicable Models | Torque |
| Fuel rail bolts (to inlet manifold - 2x) | All 450 & 452 | 8Nm |
| Fuel rail bolts (to inlet manifold) | All 451 | 9Nm |
| Fuel rail to air inlet pipe | All 451 | 9Nm |
| Throttle body bolts to inlet manifold (4x) | All 450, 451 & 452 | 9Nm |
| Inlet manifold bolts (6x) - Initial Torque Inlet manifold bolts (6x) - Final Torque |
All 450 & 452 | 12Nm 10Nm |
| Inlet manifold bolts - Initial Torque Inlet manifold bolts - Final Torque |
All 451 | 20Nm 20Nm |
| Turbo System | Applicable Models | Torque |
| Turbo oil pipe bolts (2x) | 450 599cc engines only | 7.6Nm |
| Turbo oil pipe bolts (2x) | All 698cc engines | 8Nm |
| Turbo oil line banjo bolt (to crankcase 1x) | All 450 & 452 | 10Nm |
| Wastegate actuator securing bolts (2x) | All 450 & 452 | 7Nm |
| Turbo manifold studs (7x on 599cc, 8x on 698cc) | All 450 & 452 | 6Nm |
| Turbo manifold nuts (7x on 599cc, 6x on 698cc) | All 450 & 452 | 16Nm |
| Combination valve line nuts on exhaust manifold (2x) | All 698cc engines only | 10Nm |
| Exhaust studs (2x) | 450 599cc & 452 | 8.5Nm |
| Exhaust studs (2x) | 450 698cc engines only | 9Nm |
| Banjo bolt for exhaust line to combination valve (1x) | All 698cc engines only | 34Nm |
| Bolt for combination valve to rocker cover head (1x) | All 698cc engines only | 12Nm |
| Catalytic converter pre-heater to subframe bolts (3x) | All 698cc engines only | 23Nm |
| Exhaust System | Applicable Models | Torque |
| Exhaust bolts to gearbox (2x) | All 450 & 452 | 23Nm |
| Alternator | Applicable Models | Torque |
| Alternator wiring nuts (2x) | All 450 & 452 | 8Nm |
| Alternator wiring nuts | All 451 | 10Nm |
| Alternator bracket to crankcase bolt (1x) | 599cc engines only | 27Nm |
| Alternator bracket to crankcase bolt (1x) | 698cc engines | 25Nm |
| Alternator tensioner arm to timing case - M8 | All 450 & 452 | 9.5Nm |
| Alternator tensioner arm to timing case - M6 | All 450 & 452 | 12Nm |
| Alternator tensioner adjusting nut | 599cc engines only | 27.5Nm |
| Alternator tensioner adjusting nut | 698cc engines | 25Nm |
| Alternator to timing case cover bolt | All 451 | 23Nm |
| Belt Drives | Applicable Models | Torque |
| Airconditioning belt tensioner to timing case cover (2x) | All 450 (with aircon) | 20Nm |
| Main belt tensioner to timing case cover (1x) | All 451 | 49Nm |
| Airconditioning belt tensioner eccentric bolt (1x) | All 450 & 452 (with aircon) | 21Nm |
| Induction Air | Applicable Models | Torque |
| TIK bracket to gearbox bolts (2x) - Initial Torque TIK bracket to gearbox bolts (2x) - Final Torque |
All 450 & 452 | 12Nm 9Nm |
| Spark plugs | Applicable Models | Torque |
| Spark plugs - Initial Torque Spark plugs - Final Torque |
599cc engines only | 23Nm 23Nm |
| Spark plugs - Initial Torque Spark plugs - Final Torque |
698cc engines only | 28Nm 20Nm |
| Spark plugs - Initial Torque Spark plugs - Final Torque |
All 451 | 18Nm 18Nm |
| Engine Sensors, Switches and Electronics | Applicable Models | Torque |
| Oil pressure switch | All 450 & 452 | 18Nm |
| Oil pressure switch | All 451 | 10Nm |
| Lambda O2 sensors (both sensors if applicable) | All 450 & 452 + CDI | 50Nm |
| Lambda O2 sensor - upstream | All 451 | 50Nm |
| Lambda O2 sensor - downstream | All 451 | 40Nm |
| MAP sensor bolt (1x) | All 450 & 452 | 6Nm |
| Knock sensor bolt (1x) | All 450, 451 & 452 | 20Nm |
| TDC sensor bolt (1x) | All 450 & 452 | 12Nm |
| TDC sensor bolt (1x) | All 451 | 11Nm |
| Camshaft position sensor | All 451 | 11Nm |
| Gear position sensor | All 450 & 452 | 10Nm |
| Gearbox temperature sensor | 599cc pre-2000 only | 10Nm |
| Gearbox RPM sensor | All 450 & 452 | 10Nm |
| ECU securing screws (6x) | All 450 & 452 + 450 CDI | 2Nm |
| Engine Mounts | Applicable Models | Torque |
| Engine mount - cylinder head bolts (2x) - Initial Torque Engine mount - cylinder head bolts (2x) - Retightening Torque |
All 450 & 452 | 28Nm 23Nm |
| Engine mount - back of crankcase (2x) - Initial Torque Engine mount - back of crankcase (2x) - Retightening Torque |
All 450 & 452 | 28Nm 23Nm |
| Engine mount - gearbox (2x) - Initial Torque Engine mount - gearbox (2x) - Retightening Torque |
All 450 & 452 | 28Nm 23Nm |
| Engine mount to subframe bolts (2x per mount) | All 450 & 452 | 58Nm |
| Engine mount - right engine to frame | All 451 | 56Nm |
| Engine mount - right engine to timing case | All 451 | 80Nm |
| Engine mount - left engine to carrier | All 451 | 56Nm |
| Engine mount - left engine to transmission | All 451 | 80Nm |
| Torque support engine mounts | All 451 | 115Nm |
| Carrier for front engine mount to transmission | All 451 | 23Nm |
| Carrier for front engine mount to crankcase | All 451 | 56Nm |
| Engine Subframe Assembly | Applicable Models | Torque |
| Torsion bar (K-Bar) to subframe bolts (2x) | All 450 | 65Nm |
| Torsion bar (K-Bar) to rear axle (lower nuts and bolts) | All 450 | 100Nm |
| Rear axle tube to subframe (single nut and bolt) | All 450 | 120Nm |
| Subframe to chassis bolts (4 bolts: 2 long, 2 short) | All 450 | 100Nm |
| Suspension System | Applicable Models | Torque |
| Front suspension arm top nut | All 450, 451 & 452 | 45Nm |
| Front suspension arm top spring plate nut | All 450, 451 & 452 | 60Nm |
| Front suspension arm C-clamp on rear of hub | All 450 & 452 | 46Nm |
| Front suspension arm C-clamp on rear of hub | All 451 | 30Nm + 180° |
| Rear shock absorber mounting nut and bolt (top) | All 450 & 452 | 65Nm |
| Rear shock absorber mounting nut and bolt (bottom) | 450 (698cc) & 452 | 65Nm |
| Rear shock absorber mounting bolt into captive nut (bottom) | 450 (599cc) | 65Nm |
| Anti Roll Bars | Applicable Models | Torque |
| Rear clamps holding rubber bushing to axle tube (2 bolts either side) | All 450 | 20Nm |
| Rear anti roll bar to drop link bolt (1 either side) | All 450 | 40Nm |
| Airconditioning System | Applicable Models | Torque |
| Refrigerant pipes to compressor (in engine) | All 450 & 452 | 20Nm |
| Refrigerant compressor mounting arm to cylinder head | All 450 | 10Nm |
| Refrigerant compressor to mounting bracket bolt | All 450 | 20Nm |
| Refrigerant compressor long bolt through water carrier | All 450 | 20Nm |
| Condensor radiator pipes attachment bolt (1x 10mm hex) | All 450 & 452 | 10Nm |
| Brakes | Applicable Models | Torque |
| Rear brake cylinder mounting bolts (2 bolts) | All 450, 451 & 452 | 8Nm |
| Rear brake line to brake cylinder | All 450, 451 & 452 | 18Nm |
| Wheels and Hubs | Applicable Models | Torque |
| Driveshaft bolt to rear wheel bearing | All 450 | 30Nm + 90° |
| Rear wheel bearing to axle tube (4 bolts each side) | All 450 & 452 | 65Nm |
| Steering | Applicable Models | Torque |
| Steering column mounting shells to interior cabin | All 450 & 452 | 25Nm |
| Cam bolt for attaching steering column to steering rack | All 450 & 452 | 27Nm |
| Crash bars | Applicable Models | Torque |
| Front crash bar bolts (3 either side) | All 450 & 452 | 25Nm |
