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BMW 5 Series 520i Business Line common faults.

2007–2010, saloon, petrol, 170 HP.

The fault list covers: N43B20, N43B20OL, N46NB20 engine, GM5L40, ZF6HP-BMW, ZF6HP26 transmission.

What you save stays on this device only. My saves

4 fault write-ups. All are important. 2 recalls.

If you know the year, pick it. Faults for other years drop out of the list.

Before you buy

Known faults

4 important faults

critical2

Electric water pump: silent failure, immediate overheating

critical

In these engines the water pump is not belt driven but has its own electric motor. It gains on fuel consumption, but it opens a new failure path: the pump or its electronics often simply stops with no warning. Measured in the official complaints, the typical mileage is 161,000 km (a tenth of the complaints already at 81,000, a tenth only above 257,000 km). So the common wisdom of "around 100,000 km" is early: most of the failures happen between 130,000 and 250,000 km.

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With a belt driven pump the flow weakens gradually, here the circulation stops in an instant. In urban traffic the temperature crosses the limit within minutes, the cylinder head distorts, and the repair is an engine rebuild.

Replacing a still good pump at around 120,000 to 150,000 km costs less than repairing an overheated engine. If the replacement is already in the service book, the pump has already been changed.

between 81,000 and 257,000 km

What to check

  • Watch the coolant temperature gauge after startup: it should settle evenly, not jump around
  • Standing still with a warm engine, listen for whether the cooling fan and the pump are working
  • Ask for a fault code read: codes pointing at coolant flow belong here
2 more steps in the write-up

N43: plastic chain guide breaks and the debris blocks the oil pickup

critical

On the N43 direct injection four cylinder the plastic guides of the timing chain can break. The broken pieces fall into the sump and block the screen of the oil pickup. From then on the engine is starved of oil, and that takes out the bearings first.

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If the chain is rattling, the debris may already be on its way to the oil pickup, so leaving the replacement for later is not enough.

On the same engine the injectors, the ignition coils and the NOx sensor can fail too.

What to check

  • Identify the engine first: a 320i/318i from 2005 to 2011 can be an N46 (port injected) or an N43 (direct injection). If the version does not show which engine is fitted, the build date and the engine number decide. The N43 arrived in 2007, and this fault applies only to the N43
  • On a cold start listen to the front of the engine: rattling or clicking from the timing chain
  • Ask whether the oil pressure light has ever come on, even for a moment
3 more steps in the write-up

expensive2

ZF 6HP automatic: mechatronics connector sealing sleeve leaks

expensive

In the ZF six speed automatic (BMW codes GA6HP19Z / GA6HP26Z) the electrical connector of the valve body control leaves the gearbox housing through a plastic sleeve. That sleeve and its seals age, and they let oil through.

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The symptom is irregular shifting, a gear slipping at higher revs, limp mode, a drivetrain fault code and a message on the display. The cause is the same in each case: the leak drops the hydraulic pressure, and the valve body cannot close the clutches with enough force.

The sleeve can be replaced without removing the gearbox, you only have to drop the oil pan. If it leaks for a long time, the slipping clutch and the overheating pump take the inside of the gearbox with them, and from then on it is a rebuild. The factory calls the oil a lifetime fill, but in practice the sleeve wears out around 60,000 to 70,000 miles, roughly 100,000 to 115,000 km.

between 100,000 and 200,000 km

What to check

  • On a lift look at the right side of the gearbox housing, above the oil pan: a wet, oily connector is the characteristic picture
  • On the test drive watch the shifts cold and warm: jerking, delay, slipping at higher revs
  • Ask for a fault code read from the gearbox controller: gear ratio fault, pressure regulation
2 more steps in the write-up

N43 / N53 lean burn petrol: injectors, ignition coils, NOx sensor

expensive

The N43 (four cylinder) and the N53 (six cylinder) are direct injection petrol engines built for lean burn operation. Lean burn demands far more of the injection system than a conventional port injected design, and these are exactly the three parts that gave trouble in service: the injectors, the ignition coils and the NOx sensor.

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You notice this as a rough, uneven idle, hesitation on a cold start, loss of power and higher fuel consumption. A faulty NOx sensor on its own also raises consumption, because the control unit then fuels for the worst case.

The piezo injectors are expensive each, and when one fails the replacement rarely stops at one. The N53 also uses the same high pressure pump as the N54, where pump failures led to litigation in the USA. Pump failures were reported on the N53, but it is not known whether they are as frequent as on the N54 (the N53 was not sold in the USA, so there is no official complaint data on it).

What to check

  • Identify the engine first: a 320i/318i from 2005 to 2011 can be an N46 (port injected) or an N43 (direct injection). If the version does not show which engine is fitted, the build date and the engine number decide. The N43 arrived in 2007, and this fault applies only to the N43
  • After a cold start listen to the idle for at least a minute: shaking, misfire, fluctuating revs
  • Ask for a fault code read specifically for misfire (per cylinder) and for the NOx sensor
4 more steps in the write-up

Checklist

BMW 5 Series 520i Business Line

First what you would check on any car. Then the faults of this model.

Before you buy

Checklist

The printed sheet starts with what you would check on any car. What you tick stays on this device only.

On every car

Ask the owner

Faults of this model

vinkodex.com · Before you buy it, see what can go wrong.

Official recall2 recallsShow

The manufacturer fixes these for free at a franchised dealer. Ask with the VIN whether it was done.

A12/0202/17Safety recallInjuriesno date · EU Safety Gate

The universal joint of the drive shaft might break, causing a sudden loss of propulsion.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

A12/1067/19Safety recallFireno date · EU Safety Gate

The battery positive (B+) transfer point in the boot may corrode. This can result in increased contact resistance, potentially leading to malfunction of the power supply and increased risk of fire.

Remedy: Type of economic operator taking notified measure(s): Manufacturer Category of measure(s): Recall of the product from end users Date of entry into force: Unknown

The authority's notice

Engine and transmission

3 engines · 3 transmissions

N43B20

90–125 kW (122–170 HP) · petrol

GM5L40 · 5-speed automatic, longitudinal (GM 5L40-E / A5S 360R)

automatic · 5 speed

Torque limit400 Nm
MakerGM

We built the code from the model and the gear count. The factory sheet does not state it. More than one engine code is possible. The fault list shows the faults of each. More than one transmission is possible. The gear count does not tell them apart. The code is on the side of the transmission.

Variant data

What is in this version

Factory data

Trim
520i Business Line
Body
saloon
Fuel
petrol
Transmission
automatic
Engine size
1995 cc
Power
125 kW (170 HP)
Drive
RWD
Production
2007–2010

Factory service interval

The manufacturer specifies this for this version. Of the mileage and the time, the one that comes first is the one that counts.

  • Air filter

    • 60,000 km or 4 years

  • Cabin (pollen) filter

    • 30,000 km or 2 years

  • Brake fluid change

    • first: 3 years, then 2 years(first change at 3 years, then every two years)

  • Engine oil and oil filter (BMW condition-based service)

    • LongLife25,000 km or 2 years

  • Spark plugs, petrol

    • 60,000 km or 6 years
All E60 versions

Information, not an expert opinion

We write the descriptions, and we put the source next to them. A person reviews them before they go out. They are still information, not a technical expert opinion.

  • A fault on the list does not mean the car you are looking at has it.
  • A fault missing from the list does not mean the model is fault-free. Write-ups are made model by model. Not all of them are done.
  • You decide whether to buy. This is no substitute for an inspection. That needs a workshop and a history check.
Details in the terms