Mercedes Benz Classics: Owners Operation, Service, and Repair Workshop Manuals

Mercedes M104 Engine Service Manual

The Mercedes Benz 2.8 3.6 Liter M104 Engine, Produced: 1989 to 1999


Download: M104 2.8, 3.0, 3.2, 3.4, 3.6 Liter Engine Repair Manual

Mercedes Benz M104 Engine Service Repair ManualMercedes Benz M104 Engine Repair Manual
Download: 96.8mb, 1327 pages, .pdf
Applications: W124 W129 W140 W202 W210 W463

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Mercedes Benz M104 AMG MotorThe Mercedes-Benz M104 was a straight-6 automobile engine produced from 1989 through 1999. It was 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.

Production included the 2.8-liter and 3.0-liter versions (M104 E28 and M104 E30). The M104 E32 3.2-liter engine was the last and biggest inline six-cylinder engine produced by Mercedes (AMG made the M104 3.4L E34 and M104 3.6L E36).

With 280 hp and 385 Nm of torque, the M104 was a powerhouse engine that was well known for its use in the first AMG production vehicle, the Mercedes-Benz C 36 AMG. This vehicle was capable of reaching zero to 100 km/h in 6.7 seconds, which was more than respectable in its day.

Mercedes M104 Engine Vehicle Application Survey

Mercedes Benz M104 Engine

Application Survey of Mercedes Benz M104 Engines

2.8 L M104.900 Origin:

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 air cleaner housing is made by MB.


2.8 L M104.94x

In 1993, two capacities replaced the 3.0 litre: a 2.8 L; 170.8 cu in (2,799 cc) replaced an old single-cam M103 engine and a 3.2-litre replaced a double-cam M104.98X. The 2.8 L M104 produced 142 kW (193 PS; 190 hp) at 5500 rpm and featured dual overhead camshafts driven by a duplex roller chain along with four valves per cylinder and ignition mapping control ignition system. The 2.8 L M104 was also used in the W202 C-Class model C280 and in the W140 S-Class model S280.

3.0 L M104.98x

This 3.0 L (2,960 cc) 24v DOHC was introduced as a sports car power plant. The 2.8-litre and 3.2-litre versions of M104 where installed in the following models:

  • W124 300E-24 models
  • C124 300CE-24 models
  • S124 300TE-24 models
  • R129 300SL-24 models

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.

3.2 L M104.99x

The 3.2 L (3,199 cc) version produced 170 kW (231 PS; 228 hp) at 5500 rpm. 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 the W124. This engine was found in the W124 and W210 E-Class, W140 S-Class, W463 G-Class, R129 SL-Class, Ssangyong Musso, Ssangyong Kyron, Ssangyong Rexton, Roewe W5.

AMG 3.4 L

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. Some of these engines where originally implanted in SL 3.4 AMG models. Output is 200 kW (272 PS; 268 hp) at 6500 rpm and it used Bosch KE-Jetronic (CIS-E) injection.

AMG 3.6 L M104.941/M104.992

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 280 PS (206 kW; 276 hp) at 5,750 rpm and 284 lb⋅ft (385 N⋅m) of torque at 4,000 rpm using the HFM engine management system. The engine was hand modified, so power outputs could vary slightly from 276 to 287 hp.

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: Turbocharger kits were offered for both the M103 and M104 engines by Turbo Technics, Mosselman, Lotec, 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.