BMW N52 Engine Reviews Specs Problems Reliability

BMW N52 Engine Best Review Specs Problems And Reliability

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By Scott Matthew

The BMW N52 engine is a six-cylinder piston engine (NG6 generation) with two overhead camshafts (DOHC), turbocharging, the second generation Valvetronic system and the Double VANOS, which replaced the M54 engine and was produced from 2004 to 2011 in two 2.5 liter and 3.0 liter displacement variants.

BMW N52 Engine Reviews Specs Problems Reliability

BMW N52 Engine Reviews

The N52 engine in various versions is installed on the following BMW cars:

  • 1 Series (E81, E82, E87, E88)
  • 3 Series (E90, E91, E92, E93)
  • 5 Series (E60, E61, F10, F11, F18)
  • 6 Series (E63, E64)
  • 7 Series (E65, E66, F01, F02)
  • Z3 (Coupe / Roadster)
  • Z4 (Coupe / Roadster, E89)
  • X1 (E84)
  • X3 (E83 and F25)
  • X5 (E70)

The BMW N52 is a DOCH inline six-cylinder piston engine in production for 11 years, from 2004 to 2015.

Unlike its predecessor, the BMW M54 engine, this power unit is equipped with a Valvetronic valve timing system with the ability to change valve distance according to engine speed and Dual-Vanos which dynamically controls the intake and exhaust camshafts, as well as a lighter cylinder block. made of magnesium alloy.

Like the BMW M54, this engine was equipped with electronic throttle control and a separate air intake system, called DISA (later BMW changed this technology, keeping its name).

The BMW N52 engine made its debut in 2004 on the sixth series BMW models on the rear of the E63 – 630Ci and the third series – the E90 330i. Many BMW models (3 series, 5 series, X3, Z4 and others) went on sale with the N52 engine.

Since 2007, the engines have been gradually replaced by replacement engines for the N53, which proved unsuitable for the North American, Australian and Malaysian markets due to the high sulfur content in the fuel. Therefore, in these countries, the N52 unit continued to be used until the next modification after the N53 – the turbocharged N20 4 cylinder engine.

BMW N52 Engine Design

Crankcase materials are magnesium and aluminum. Magnesium is used to reduce weight, but it is more susceptible to corrosion. Moreover, magnesium is prone to cracking when exposed to high temperatures.

Hence, magnesium alone or in standard alloys is unsuitable for the high stress conditions that major engine components typically experience. Nonetheless, BMW decided to use magnesium alloy for the crankcase outer shell, using aluminum for the inside, which compensates for the lack of magnesium as a structural material.

N52 engine cylinder liners are made of aluminum, cylinder liners are made of allusil, an aluminum alloy which is widely used as a protective shell. When the engine starts, the allusil provides a durable silicone coating on the cylinder walls. BMW switched from using nicosyl coating to using allucyls in 1996 to address corrosion problems when using fuels containing sulfur.

BMW N52 Engine Problems And Reliability

The N52 engine came with a piston that failed: the distance between the piston and cylinder was enormous. Therefore, piston rings are very bad at removing burnt oil in the combustion chamber. Replacing the piston rings with new ones did not solve the problems. BMW has released two revisions to the piston – the third type piston, since May 2010, turned out to be the most successful and solved the problems of consumption of oil for waste.

The valve stem seal on the hot BMW N52 petrol engine quickly browns and oil begins to leak into the valve bag. Then enter the combustion chamber. The problem occurs every 80,000 – 100,000 km. Valve stem seal replacement helps. Most of the carbon deposits can fall into the cylinder, paint between the cylinder walls and the piston – a spasm appears.

The BMW N52 engines are very picky about oil quality. In addition, due to the high temperature of the thermostat (operating temperature – 95 degrees), the oil in them quickly breaks down and becomes coke. Therefore, you should not save on oil and change it at intervals of more than 10,000 km. Due to low quality or old oil, the engine wears out quickly: seizures appear in the liner, the camshaft is worn, spasms can form on the allusil surface of the cylinder.

The crankcase ventilation valve plays a part in contaminating the engine with burnt oil and an accelerated “dropping” in the intake valve. It stops functioning if the membrane breaks. Therefore, the exhaled gas is not removed from the crankcase and the space under the valve cover.

If a BMW N52 engine starts clinking, it’s possible oil has left the hydraulic lift. This is due to a drop in the oil level in the sump or from frequent short trips. The pumpable hydraulic lift keeps engine speed at 3500 rpm for several minutes.

However, this method will not work if poor quality oil is poured into the engine or changed over long intervals. Then, the oil fraction accumulates in the hydraulic compensator, interrupting its work.

All early N52 engines inherently “ticked” at idle as hydraulic lifters served. Engines made after November 31st have improved cylinder heads that no longer produce clattering sound.

The main reason for engine unevenness, triplets, engine vibration is the Valvetronic system malfunction. Usually the solenoid valve fails or the servo drive runs out: motors and worm gears.

The reason the BMW N52’s engine shuts down while slowing down and generally pulls weakly is a clogged catalyst, its complete failure. The catalyst can be changed, which is very expensive, or replaced with a fire arrester.


The BMW N52 engine is a new step in the development of BMW petrol powertrains. More technological, economical and powerful, they demand more attention to maintenance, oil and filter quality. However, BMW fans are not deterred by all of these problems.

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