The Most Common VW / AUDI 1.4 TDI (BNM) Engine Problems

The BNM engine is a turbocharged 1.4 liter diesel engine. The maximum power of the engine is about 70 hp. s., torque – 155 Nm at 2800 rpm.

This in-line ICE has 3 cylinders, 6 valves, as well as a SOHC system. The cylinder block is made of cast iron, the cylinder head is made of aluminum alloy.

The timing drive works on a belt. The belt drive is recommended to be changed every 90 km to avoid a break. The BNM engine is under the hood of cars such as SEAT, Skoda, VW, Audi.

Read Also: The Most Common VW / AUDI 1.2 TDI (ANY) Engine Problems

1.4 TDI (BNM) Engine Specs

Volume (cm3)1422
Power (hp)70
Torque155 Nm
Timing driveBelt
Environmental classEuro 3/4
Fuel typeDT
ICE featuresbalance shaft
Supply systemPump-Injectors
hydraulic liftersYes
Cylinder blockCast iron R3
cylinder headaluminum 6v
Cylinder diameter79.5 mm
piston stroke95.5 mm
Compression ratio19.5
Phase regulatorNot
Engine oil4.3L 5W-30
Average resource250,000 km

1.4 TDI (BNM) Engine Advantages And Reliability

The main advantage of the BNM engine is its economy, low consumption of diesel fuel. The engine is lightweight and compact.

This is possible due to the in-line placement of 3 cylinders, although this design also has its drawbacks. A good resource of 250,000 km can be counted among the advantages of the engine.

Read Also: Most Reliable (VAG) Volkswagen Audi Gasoline & Diesel Engine

Disadvantages and Problems of the 1.4 TDI (BNM) engine

The most common problems in the BNM engine include noise during operation, but all diesel engines have this drawback. After a run of 180,000 km, breakdowns often begin.

Nozzles wear out – this is signaled by an indicator that registers a problem with glow plugs. Replacing nozzles is not a cheap procedure, so a detailed diagnosis must be carried out before replacement.

Another problem after a run of 150.000-180.000 km is the axial play of the crankshaft. But the most tangible drawback is in 3 cylinders, because of this there is noise.

It will require balancing the power engine at around 200,000 km of run. Not every master provides such a complex service.

Therefore, experts advise buying engines with 4 cylinders – if the number of cylinders is even, they balance each other.

1.4 TDI (BNM) Engine Tuning prospects

For the BNM turbo engine, the best tuning option would be firmware. With good firmware from a specialist, an increase of 20 liters is possible.

But after such tuning, a decrease in the resource is not excluded, so it is up to the owner of the car to decide whether this event is worth the money or not.

Read Also: The 9 Most Reliable Skoda Engine Ever Made

Applicability of 1.4 TDI (BNM) engine

Skoda : Fabia (2004-2010), Roomster (2004-2010)

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