The 4M41 is a robust 3.2-liter diesel engine developed by Mitsubishi and used in various Mitsubishi models, including the Pajero. Here’s an overview of the engine’s specifications, problems, and tuning options:
Characteristics of the 4M41 engine
|Production||Kyoto Engine Plant|
|Years of Manufacture||1999-present|
|Cylinder Block Material||Cast Iron|
|Number of Cylinders||4|
|Valves per Cylinder||4|
|Piston Stroke, mm||105|
|Cylinder Diameter, mm||98.5|
|Compression Ratio||16.0; 17.0|
|Engine Capacity, cc||3200|
|Engine Power, hp/rpm||165/4000; 175/3800; 200/3800|
|Torque, Nm/rpm||351/2000; 382/2000; 441/2000|
|Fuel Consumption (Pajero 4)||City: 11.0 l/100 km, Highway: 8.0 l/100 km, Mixed: 9.0 l/100 km|
|Oil Consumption, g/1000 km||Up to 1000|
|Engine Oil||5W-30; 10W-30; 10W-40; 15W-40|
|Oil Change Carried Out, km||15,000 km (or better 7,500 km)|
|Engine Operating Temperature, degrees||90|
|Engine Life, thousand km||400+|
|Tuning, hp Potential||200+|
|The Engine was Installed In||Mitsubishi Triton, Pajero, Pajero Sport|
- Cylinder Block: The 4M41 engine is a 4-cylinder diesel engine with a cast iron cylinder block. It features a 98.5 mm cylinder diameter and a 105 mm piston stroke, resulting in a displacement of 3.2 liters.
- Cylinder Head: The engine is equipped with an aluminum cylinder head with direct fuel injection. It features two camshafts and four valves per cylinder. The intake valves have a diameter of 33 mm, and the exhaust valves are 31 mm. The valve stem thickness is 6.5 mm.
- Valve Adjustment: Valves need to be checked and, if necessary, adjusted every 15,000 kilometers. The recommended valve clearances when cold are 0.1 mm for intake valves and 0.15 mm for exhaust valves.
- Timing Drive: The engine uses a single-row timing chain to drive the camshafts. It’s worth noting that this timing chain may become noisy after covering around 200,000 kilometers.
Variants of the 4M41 Engine
- Early Version: The initial version of the 4M41 engine produced 165 hp at 4000 rpm and had a torque of 351 Nm at 2000 rpm. It used an MHI TF035HL turbine.
- Common Rail Versions: From September 2006, Mitsubishi introduced Common Rail versions of the 4M41 engine. These models featured an IHI RHV5S turbine with variable geometry and other modifications to enhance power and reduce emissions. Power output increased to 175 hp at 3800 rpm and torque reached 382 Nm at 2000 rpm.
- Upgraded Versions: In 2010, Mitsubishi introduced upgraded versions of the 4M41 engine with modified IHI RHV5S turbines with variable geometry. Power was further increased to 200 hp at 3800 rpm, and torque reached 441 Nm at 2000 rpm.
4M41 Engine Problems and Disadvantages
- Timing Chain Noise: Timing chain noise may arise after 150,000 to 200,000 kilometers, indicating the need for a timing chain replacement before it breaks.
- Starting Issues, Smoking, Power Loss: If the engine doesn’t start, produces smoke, or experiences a power loss, the injection pump may be the culprit. Use of low-quality diesel fuel can reduce the life of the injection pump.
- Whistling Noise: A stretched alternator belt may be responsible for a whistling noise. Replacing or tightening the belt usually resolves the issue. The crankshaft pulley may also require attention, as it can deteriorate approximately every 100,000 kilometers.
Regular cleaning of the EGR (Exhaust Gas Recirculation) valve is necessary, as low-quality fuel can lead to carbon deposits, affecting the intake manifold.
Tuning the 4M41 Engine
Tuning an older engine like the 4M41 should be approached with caution, as it may already have substantial wear and tear. However, for the latest versions, chip tuning can be considered to increase power:
- The 165 hp engine can be tuned up to 190 hp with torque around 410-420 Nm.
- Models with 190-200 hp can be tuned to reach 240 hp at 3500 rpm with torque exceeding 500 Nm at 2000 rpm.