M52B25 — 2.5L Petrol (1998-2000)
- Power Output
- 170hp
- Years Fitted
- 1998-2000 (E39 pre-facelift)

BMW 523i SPECIALISTS
Get quotes today from trusted UK BMW 5 Series 523i engine specialists. Compare prices on reconditioned, rebuilt and used engines for your E60, E61 or F10 523i - all with verified compatibility and warranty-backed supply.
How it works
Clear information first, then the right engine and specialist for your exact vehicle.
Variant History
The BMW 523i has served as the entry-to-mid-range six-cylinder petrol option across three generations of the 5 Series. From the E39's M52 through to the F10's N53, the 523i badge has consistently denoted a 2.5-litre naturally aspirated inline-six - though power output and engine architecture evolved significantly over its production life.

M52B25, 2.5L inline-six, 170hp - E39 523i launched, replacing the earlier M50-based 525i
M54B25, 2.5L inline-six, 192hp - E39 facelift introduced Double-VANOS and drive-by-wire throttle
N52B25A, 2.5L inline-six, 177hp - E60 523i debuts with magnesium-aluminium composite construction, Valvetronic and electric water pump
N52B25BE, 2.5L inline-six, 190hp - E60 LCI (facelift) 523i gains power increase
N53B25A / N53B25UL, 2.5L inline-six, 190hp - Euro 5-compliant direct-injection version introduced for markets with low-sulphur fuel
N53B30A, 3.0L inline-six, 204hp - F10 523i switches to 3.0-litre displacement while retaining the 523i badge - this marked the end of the true 2.5-litre 523i era
Every engine fitted to the BMW 5 Series 523i is covered below, with UK rebuilt pricing and known failure points.
Engine Codes & Pricing
Find your exact engine code, specs and UK replacement cost guide.

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-> Get quotes for M52B25 BMW 5 Series 523i engine replacementCommon Problems
The BMW 523i's six-cylinder petrol engines - particularly the N52 and N53 families - are broadly robust units, but they have well-documented weak points that can become costly as mileage climbs. The N52 (2005-2010) is the most widely fitted 523i engine in the UK and dominates replacement demand for this variant, while earlier M52/M54 units have their own set of ageing-related issues. Rebuilt engines through EnginesMarket include upgraded components addressing the original failure point, plus a minimum 12-month unlimited-mileage warranty.
Common failure points and repair options
Whether your 523i is an E39, E60 or F10, our network of UK BMW specialists can supply a replacement engine with a minimum 12-month warranty - often at a fraction of main dealer cost. Enter your registration above and compare quotes from vetted suppliers today.
FAQ
Everything BMW 5 Series 523i owners usually ask before choosing a rebuilt, reconditioned or used replacement engine.
Why Choose Us
Comparing quotes for your BMW 5 Series 523i is completely free and carries no obligation. Whether you need a used N52B25A for an E60, a reconditioned N53B25A for an LCI car, or a rebuilt N53B30A for an F10 - enter your registration above and let our vetted UK specialists provide transparent, itemised pricing for your exact engine code.
Compare quotes from trusted UK BMW 5 Series 523i engine specialists with warranty-backed rebuilt, reconditioned and used options nationwide.