E85/E86 · 2006–2008

BMW Z4 2.5si E85/E86 · 218 hp (2006 to 2008)

The BMW Z4 2.5si of the E85/E86 generation uses the N52B25 petrol engine with 218 hp. Oil, timing drive and known issues of this engine are covered in the “Engine” block on this page.

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Technical specifications

Fuel
Petrol
Power
218 PS / 160 kW
Displacement
2 497 cm³
Cylinders
6
Engine code
N52B25
Period covered
2006–2008
Documented market
Europe

Transmission

  • Manual · 6 speeds
  • Automatic · 6 speeds

Figures apply to the cited configuration and market; equipment and transmissions may vary by production date.

Specification source : [1] AutoKarnet

This version

218 hp (160 kW), rear-wheel drive, 6-speed manual or 6-speed automatic. Built from 2006 to 2008.

AutoKarnet advice

In the range

It sits between the 2.5i (192 hp) and the 3.0i (231 hp). The N52B25 engine is also fitted to: BMW X3 (E83), BMW Z4 (E89).

AutoKarnet advice

BMW N52 petrol engine (3.0 l naturally aspirated six)

This applies to every car fitted with the N52 engine.

What the N52 is

A naturally aspirated 2,996 cc inline six-cylinder petrol engine (88.0 × 85.0 mm) with a composite magnesium-aluminium crankcase and Valvetronic II. BMW launched it in 2005 in the E60/E61 5 Series and the E90 3 Series (330i, then the 325i with a lower-output version of the same 3.0), in two output stages: OL (upper, with the DISA resonance intake) and UL (lower, without DISA). BMW’s workshop documentation also lists an N52K, fitted for example to the 1 Series 125i and 130i.

Source : [7] [6] [4]

Engine oil

Oil change with filter: 6.5 l for the N52 B30 and N52K B30 according to TIS data; 7.0 l on an N52K with the auxiliary engine oil cooler. BMW’s training material specifies SAE 5W-30. Longlife-04 is approved for petrol engines only in the EU, Switzerland, Norway and Liechtenstein; elsewhere, use the approval BMW specifies for the country.

Source : [3] [4] [2] [7]

Timing drive

Chain, at the front of the engine, on both the N52 and N52K: replacement goes through removing the cylinder head cover, the tensioner, the front radial seal and the vibration damper. No interval is set: it is a repair.

Source : [5] [6]

Magnesium block: workshop precautions

Ancillaries attached to the magnesium crankcase use aluminium bolts (blue heads): a steel bolt would cause contact corrosion. For the same reason, the gaskets between the aluminium cylinder head or oil pan and the magnesium block must not be damaged. Point this out to a workshop unfamiliar with the engine.

Source : [7]

Maintenance and records

Oil and filter change

Per CBS, at the latest 24 months

24 months

Due date calculated by the car from use. BMW Longlife-approved oil suited to the engine.

Source [1]

Pads and discs

Per wear sensors

Front and rear tracked separately by CBS.

Source [1]

Brake fluid

Every 24 months

24 months

Time-based replacement, whatever the mileage.

Source [1]

Questions about this version (2)

Which engine is in the BMW Z4 2.5si E85/E86?

The N52B25 petrol engine (2 497 cc), 218 hp (160 kW).

AutoKarnet advice

Which oil for the BMW Z4 2.5si?

A BMW Longlife-approved oil suited to the N52B25 engine. The “Engine” block on this page and the vehicle’s handbook give the exact approval.

AutoKarnet advice

Documentary sources

  1. [1] Rédaction AutoKarnet

    AutoKarnet · FR · Europe · Synthèse éditoriale AutoKarnet · Accessed 09/10/2026

  2. [2] BMW TIS — BMW Quality Longlife-04

    BMW AG — TIS (archive) · EN · Europe · SI 11 03 04 (156) · revision 09/2005 · Accessed 08/10/2026

  3. [3] BMW TIS — Oil Supply N52 / B30

    BMW AG — TIS (archive) · EN · Europe · TD 11 40 · engine-level data, N52 B30; archive navigation is E90 · Accessed 08/10/2026

  4. [4] BMW TIS — Oil Supply N52K B30

    BMW AG — TIS (archive) · EN · Europe · TD 11 40 · with filter; with auxiliary engine oil cooler · Accessed 08/10/2026

  5. [5] BMW TIS — Replacing timing chain (N52)

    BMW AG — TIS (archive) · EN · Europe · RA 11 31 · N52 · Accessed 08/10/2026

  6. [6] BMW TIS — Replacing timing chain (N52K)

    BMW AG — TIS (archive) · EN · Europe · RA 11 31 · E88 archive, “1 Series 125i (N52K) Convertible” · Accessed 08/10/2026

  7. [7] BMW Technical training — New Generation 6-Cylinder N52

    BMW of North America — Technical Training · EN · USA · Introduction (E60, E61, E90; 330i and 325i, 2005) · Technical data N52B30 (engine oil SAE 5W-30) · designations OL/UL · magnesium crankcase, aluminium bolts · Accessed 08/10/2026

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