Mercedes-Benz M104 engine

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Mercedes-Benz, Techno-Classica 2018, Essen (IMG 9644).jpg
ManufacturerMercedes-Benz AG
ConfigurationStraight-6 (Except M104.900, refer VW VR6)
Displacement2.8 L; 170.8 cu in (2,799 cc) M104.94x
3.0 L; 180.6 cu in (2,960 cc) M104.98x
3.2 L; 195.2 cu in (3,199 cc) M104.99x
Block materialCast iron
Head materialAluminium
ValvetrainDOHC 4 valves x cyl. with VVT
Compression ratio9.2, 10.0 and 10.5 on AMG models
Fuel systemBosch KE-Jetronic electronically controlled, mechanical fuel injection (CIS-E)/Bosch Motronic integrated electronic injection/ignition (HFM)
Fuel typeGasoline
Oil systemWet sump
Cooling systemWater cooled
Power output193–280 PS (142–206 kW; 190–276 hp) SAE
Torque output265–385 N⋅m (195–284 lb⋅ft) at 4600 rpm M104.98x
PredecessorM 103
SuccessorM 112

The Mercedes-Benz M104 is a straight-6 automobile engine produced from 1989 through 1999. It has a double overhead cam design with 4 valves per cylinder. It replaced the M103 and was replaced by the M112 V6 starting in 1997. The M104 continued in production until 1999 where its last use by Mercedes-Benz was in the W140 chassis.

2.8 L M104.900[edit]

Mercedes needed a compact 6 cylinder for their vans and asked Volkswagen if they could use the VR6 Golf/Jetta engine. An agreement was reached and the engines were sold semi completed to MB. Basically only the engine cover and aircleaner housing is by MB.

3.0 L M104.98x[edit]

This 3.0 L (2,960 cc) 24v was introduced as a sports car resp. top model completing the line-up of M103 12V engines. The M104 featured dual overhead camshafts and four valves per cylinder. The M103 and M104.98x were later replaced by the 2.8-litre and 3.2-litre versions of the M104. Bore is 88.5 mm (3.48 in) and stroke is 80.2 mm (3.16 in) with a compression ratio of 10:1.[1] The 3.0 L (2,960 cc) M104 produced 217 to 228 hp (162 to 170 kW; 220 to 231 PS) (without catalytic version) and features KE-Jetronic fuel injection, cylinder specific ignition-timing, variable valve timing and under-piston cooling jets.


2.8 L M104.94x[edit]

In 1993, two capacities replaced the 3.0 litre: a 2.8 L; 170.8 cu in (2,799 cc) replaced the old single-cam M103 engine and the 3.2 litre M104.99x replaced the double-cam M104.98x. The 2.8 L M104 produced 190 hp (193 PS; 142 kW) at 5500 rpm. Maximum torque was 270 N⋅m (199 lb⋅ft) at 3750 rpm. Bore is 89.9 mm (3.54 in) and stroke is 73.5 mm (2.89 in). Lubrication system is pressure circulation lubrication. Amount of oil in engine was 7.5 litres (2.0 US gal; 1.6 imp gal) (which was later revised to 7 litres (1.8 US gal; 1.5 imp gal) and amount of coolant in engine is 9 litres (2.4 US gal; 2.0 imp gal). The camshaft is driven by duplex roller chain. The electrical starter motor produces 1.7 kW (2.3 PS; 2.3 hp). Ignition system is ignition mapping control.


3.2 L M104.99x[edit]

The 3.2 L (3,199 cc) version produced 170 kW (231 PS; 228 hp) at 5500 rpm and 310 N⋅m (229 lb⋅ft) at 3750 rpm. Bore is 89.9 mm (3.54 in) and stroke is 84 mm (3.31 in). On all 24 valve M104 engines Intake valves are 35 mm (1.4 in) and the exhaust valves are 31 mm (1.2 in). The Compression ratio is the same 10.0:1 on all W210, R129,and W140 but it did differ from 9.2:1 to 10.0:1 on W124 (M104.992).[2]


AMG 3.4 L[edit]

There were 3.4 L conversions done to the 3.0 L M104.980 by AMG, prior to their formal cooperation with Daimler Benz.

AMG developed a 3.4 L M104 that was used principally in the 300E AMG 3.4, AMG 3.4 CE and 300TE-3.4 AMG (Mercedes-Benz W124) vehicles, produced between 1988-1993. Few of this engine was originally on SL 3.4 AMG. Bore and stroke is 91.5 mm × 84 mm (3.60 in × 3.31 in). Output is 268 hp (200 kW; 272 PS) at 6500 rpm and 330 N⋅m (243 lb⋅ft) at 4500 rpm. The engine oil capacity is 7.5 litres (2.0 US gal; 1.6 imp gal) and coolant volume is 9 litres (2.4 US gal; 2.0 imp gal). It uses Bosch KE-Jetronic (CIS-E) injection.

AMG 3.6 L M104.941/M104.992[edit]

There were 3.6 L conversions done to both the M103 and M104 by Brabus, among others.

AMG developed a 3.6 L; 220.1 cu in (3,606 cc) M104 that was used in the W202 C36 AMG (W202) from M104.941, the W124 E36 AMG (W124) from M104.992, the E36 AMG (W210), and the G36 AMG (W463) vehicles.

The AMG 3.6 M104 was rated at 276 hp (206 kW; 280 PS) at 5,750 rpm and 284 lb⋅ft (385 N⋅m) of torque at 4,000 rpm using the HFM engine management system. Bore and stroke is 91 mm × 92.4 mm (3.58 in × 3.64 in). The Compression ratio is 10.5 AMG later conceded that since the engine was hand modified, power outputs could vary slightly from 276 to 287 hp (206 to 214 kW; 280 to 291 PS).

The boost in displacement was obtained by boring the 2.8 litre M104 block by 2.1 mm (0.083 in) and using a highly modified version of the crankshaft from the 3.5L OM603 to increase throw by 18.9 mm (0.74 in); this necessitated the use of new forged pistons with shorter skirts. A larger intake crossover pipe, freer flowing exhaust, a unique intake camshaft, minor changes to the cylinder head, and modifications to the HFM fuel computer also contribute to the increase in power.

AMG 3.6 Liter M104 in a W124 E36T AMG

Turbo Conversions[edit]

Turbocharger kits were offered for both the M103 and M104 engines by Turbo Technics, Mosselman, Lotec, MAD Modify, Turbobandit and other tuners. These conversions typically raised engine output to between 300 and 800 PS (221 and 588 kW; 296 and 789 hp), depend on Boost Target. During the 1990s UK customers were able to buy new vehicles equipped with a Turbo Technics conversion directly from Mercedes dealer Hughes of Beaconsfield (limited run of 75 conversions). Today turbocharger kits for M103-M104 engines are available from later tuners in Europe and Asia.



  1. ^ "Mercedes Benz W124 Cabrio 300 CE-24 Cabrio Technical Specs, Dimensions". Retrieved 2019-03-16.
  2. ^ "M104 3.2L Engine Specifications And Review on". Retrieved 2019-03-16.