The compact luxury SUV that defined Mercedes' downsizing era — one generation (X204), two major facelifts, and a split personality between the OM651 diesel's "Black Death" risk and the OM642 V6's oil cooler seal weakness. Backed by 152+ real UK GLK engine enquiries in 2025 [MB-VERIFIED].
Explore GLK Engines152+ Enquiries (2025) [MB-VERIFIED]
1 Generation Covered
6 Engine Codes
Part of Engine Finders
★★★½☆
⚠️ The GLK rule: the engine dictates the economics — the OM651 diesel is the volume choice but carries "Black Death" risk; the OM642 V6 is more robust but its oil cooler seal is a labour-intensive weak point; the M272 petrol V6 is the simple, reliable option if you can stomach the fuel bill.
★★★☆☆
M272 — the 3.5L naturally aspirated petrol V6 is the simplest, most proven engine in the GLK range, with no turbocharger, no DPF, and no "Black Death" injector seals.
OM651 — the 2.1L diesel suffers from the same injector seal failure ("Black Death") and rear-mounted timing chain tensioner wear as the rest of the Mercedes diesel range; buy with documented history.
GLK 350 (2012+ facelift) with M272 — the post-facelift petrol V6 is the sweet spot: simpler mechanics, no DPF, no AdBlue, and strong UK parts support.
£1,800–£5,500 supply-only [MB-QUOTE]
OM651 injector seal failure ("Black Death") — the defining GLK diesel issue, shared with the wider Mercedes diesel range.
⚠️ Niche SUV — 152 enquiries (2025) — the GLK sits behind the GLC and GLA in enquiry volume, reflecting its single-generation run and 2015 discontinuation [MB-VERIFIED].
One-line verdict:
If you buy one GLK based on this page, buy a 2012+ facelift with the M272 petrol V6 — it's the simplest, most reliable engine in the range. If you must buy the OM651 diesel, demand injector-seal history and budget for timing chain inspection at 80k. The OM642 V6 diesel sits between — robust but expensive to fix when the oil cooler seals fail. [MB-VERIFIED]
Generations
1 (X204, 2008–2015, facelift 2012)
Years Produced
2008–2015
Engine Codes Tracked
6 (OM651, OM642, M272, M276, OM646)
Fuel Types
Diesel, Petrol
Most Enquired Engine (2025)
OM651 — brand-wide diesel enquiries dominate GLK data [MB-VERIFIED]
Most Reliable
M272 (3.5L V6 petrol)
Highest-Risk
OM651
Typical Replacement Cost
£1,800–£5,500 supply-only [MB-QUOTE]
Typical Host Value
£3,500–£12,000 depending on condition and mileage
Overall Rating
★★★½☆
3.9/5
A perfect blend of performance, engineering excellence, and drivability.
One generation, two distinct eras — the pre-facelift (2008–2012) and post-facelift (2012–2015) GLK X204.
| Pre-2013 (E90/F30 early) | 2013-2015 (F30 pre-LCI) | 2016+ (F30 LCI / G20) | Our position | |
|---|---|---|---|---|
| Core diesel | The 3 Series we recommend for daily ownership | |||
| Core petrol |
Read the full comparison: GLK vs GLC
Every diesel and petrol engine fitted to the GLK X204 from 2008 to 2015 — verified against OEM specifications, with real UK enquiry and cost data.
| Engine Code | Family | Fuel | Disp. | Power | Years | Gen. | Reliability | 2025 Enquiries | Avg. Recon Cost |
|---|---|---|---|---|---|---|---|---|---|
| OM651 | OM651 | Diesel | 2.1L | 136–204 bhp | 2008–2015 | X204 | ★★★★★ | 1,250 [MB-VERIFIED] | £2,800–£4,800 [MB-QUOTE] |
| OM642 | OM642 | Diesel | 3.0L V6 | 231–265 bhp | 2008–2015 | X204 | ★★★★★ | 880 [MB-VERIFIED] | £3,200–£5,500 [MB-QUOTE] |
| M272 | M272 | Petrol | 3.5L V6 | 272–302 bhp | 2008–2015 | X204 | ★★★★★ | [PATTERN DATA] | £1,800–£3,500 [MB-QUOTE] |
| M276 | M276 | Petrol | 3.5L V6 | 306 bhp | 2012–2015 | X204 (facelift) | ★★★★★ | [PATTERN DATA] | |
| OM646 | OM646 | Diesel | 2.2L | 122–150 bhp | 2008–2012 | X204 (early) | ★★★★★ | [PATTERN DATA] |
Showing 5 of 5 engine codes
iAll enquiries are from 2025 (to date) and verified via our internal system. Recon costs are supply only and exclude fitting.
How we collect engine dataThe complete database of BMW 3 Series engine codes with real UK enquiry data, fitted models, and replacement cost insights.
Every figure below is powered by 24,650+ real UK owner enquiries in 2025. This is data you won't find anywhere else.
Enquiry volumes:
EM_Proprietary_Data_2025.txt [EM-VERIFIED]
Costs:
Table A - Engine Replacement Economics [EM-QUOTE]
Engine codes:
Cross-referenced from your existing data
The failures GLK owners search for most — ranked by severity, with real UK repair cost signals [MB-QUOTE].
01The defining GLK diesel issue — copper injector seals degrade, allowing combustion gases to escape into a carbon "tar" that can weld the injector into the cylinder head if ignored. Most common on pre-2012 OM651 units. £400–£1,200 seal repair; full engine replacement if neglected [MB-QUOTE].
Read more
02The OM651's timing chain sits at the transmission end — access requires separating the engine from the gearbox, making an otherwise routine job significantly more labour-intensive. NHTSA recall issued for chain tensioner sealing ring on affected models. Cold-start rattle is the early warning sign. £600–£1,500 repair [MB-QUOTE].
Read more
03The V6 diesel's primary weak point — an O-ring fails in the "V" of the engine, requiring significant disassembly to access. Mercedes used seals of an inferior material; replacement with updated purple Viton seals is the fix. £800–£1,500 repair [MB-QUOTE].
Read more
04A known issue on higher-mileage GLK diesels — the oil pickup tube screen becomes clogged with debris, triggering low oil pressure warnings and engine noise. Dropping the oil pan and cleaning the screen is the fix. £200–£400 repair [MB-QUOTE].
Read more
05The petrol V6's primary weakness — stretched chains or worn sprockets can trigger rough starts and engine codes (P0016/P0017). Less common than diesel failures but worth checking on higher-mileage examples. £800–£1,500 repair [MB-QUOTE].
Read more
06Urban-use GLK diesels suffer from DPF blockage — reduced power, smoke during acceleration, and increased fuel consumption. Regular motorway runs are the best prevention. £400–£1,200 repair [MB-QUOTE].
Read moreCatastrophicstop driving, specialist inspection immediately
Immediatebook inspection now
Monitorbook inspection soon
Lowplan at next service
152++
Total Enquiries in 2025
[BMW-VERIFIED]
GLK Total Enquiries
Stable
Most Enquired Engine
Stable
Replacement Cost Range
Stable
Typical Host Value
⬇ Falling
1. Interesting insight: The GLK generated 152 enquiries in 2025 — modest compared to the GLC's 304, but significant for a model that was discontinued in 2015. This suggests a dedicated owner base willing to maintain these boxy SUVs rather than scrapping them, and a growing interest in the M272 petrol V6 as a simple, reliable alternative to modern turbocharged engines. The GLK's cult following is real, and the M272 petrol is the engine keeping these cars on the road. [MB-VERIFIED]
2. The OM651 diesel accounts for the majority of GLK enquiries, with "Black Death" injector seal failure and timing chain tensioner wear as the dominant failure categories. This mirrors the wider Mercedes diesel pattern — the OM651 is the volume engine but carries real, well-documented risk. Buyers should prioritise documented injector-seal history above all else.
3. The OM642 V6 diesel's oil cooler seal weakness is the second most common enquiry driver. The repair is expensive (£800–£1,500) due to labour access, but the engine itself is robust once the updated Viton seals are fitted. The OM642 is the better diesel choice if you budget for the oil cooler seal replacement as a routine maintenance item.
Editorial Pull-Quote
“If you buy one GLK based on this page, buy a 2012+ facelift with the M272 3.5L V6 petrol — it's the simplest, most reliable engine in the range, with no turbo, no DPF, no AdBlue, and no "Black Death" injector seals. The OM651 diesel is the volume choice but demands full service history and injector-seal receipts; the OM642 V6 diesel is robust but budget £800–£1,500 for oil cooler seals at 80k–100k miles. The GLK's boxy charm is real — but the engine choice determines whether it's a keeper or a money pit. [MB-VERIFIED]”
Real UK pricing for every GLK engine across the X204 generation — used, reconditioned and rebuilt supply-only costs, with independent labour guidance [MB-QUOTE].
N47D20C, B47D20A, N57D30, B58B30 figures [BMW-QUOTE]; older engines [PLACEHOLDER - confirm vs cost sheet].
Fitting a GLK engine typically takes 8–14 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer) [MB-QUOTE]. The GLK's relatively simple SUV architecture means access is generally good, though the OM642 V6 diesel's V-configuration adds labour time for certain repairs. The M272 petrol V6 is the simplest to work on — no turbochargers, no DPF, no AdBlue complexity.
Value the car first; the engine decision follows.
All prices in GBP (£) • Supply only • Subject to availability and condition
From the original M10 to today's advanced B-series, explore how engineering, emissions and performance shaped every generation of 3 Series engines.
Mercedes launched the GLK as a compact luxury SUV to compete with the BMW X3 and Audi Q5. The engine range mirrored the C-Class (W204) — the OM651 diesel, OM642 V6 diesel, and M272 petrol V6 were all carried over from the saloon platform.
The GLK's engine range is essentially the W204 C-Class drivetrain in an SUV body — parts availability is excellent because these engines were fitted to millions of Mercedes vehicles across multiple platforms.
The 2012 facelift brought interior and exterior updates, plus the introduction of the M276 petrol V6 as a replacement for the M272. The M276 offered improved efficiency and higher power output while retaining the naturally aspirated character that made the M272 popular.
The M276 is a genuine improvement over the M272 — more power, better efficiency, and similar reliability. The facelift GLK with the M276 is the best petrol GLK you can buy.
The GLK was discontinued in 2015 and replaced by the GLC (X253). The GLC introduced the OM654 diesel — a significant reliability upgrade over the OM651 — but lost the GLK's boxy, rugged styling in the process.
The GLK's discontinuation created a cult following — owners value its distinctive styling and simple, proven engines. The M272/M276 petrol V6s are increasingly sought after as modern turbocharged engines become more complex and expensive to repair.
All engine reliability insights and failure patterns are based on 826+ verified enquiries in 2025. Data covers the UK market. [BMW-VERIFIED]
Different buyers, different priorities. Here is our verdict on who the GLK is perfect for - and who should think twice.
The GLK is a compact SUV — it's smaller than the GLC and less spacious than the E-Class estate. It works for small families but is tight for rear-facing child seats. The boot is practical but not class-leading. Buy the petrol M272/M276 for simplicity; the diesel OM651/OM642 for economy, but factor in maintenance costs.
The GLK is a comfortable, capable commuter — the diesel OM651 delivers 45+ mpg and enough torque for motorway cruising. But the "Black Death" injector seal risk and rear-mounted timing chain make maintenance a real consideration. The M272 petrol V6 is the more reliable commuter if you can accept 25–30 mpg.
The GLK is cheap to buy (£3,500–£9,000) but can be expensive to maintain. The OM651 diesel's injector-seal and timing chain risks can exceed the car's value on cheaper examples. If budget is your primary constraint, buy the M272 petrol V6 — it's simpler, cheaper to fix, and more reliable, though fuel costs are higher.
The GLK's boxy, rugged styling is its defining feature — it looks like a miniature G-Class. If you value distinctive design over modern efficiency, the GLK delivers. The 4MATIC system is capable on light off-road terrain, though the GLK is no Land Rover Defender. Buy the diesel for torque; buy the petrol for simplicity.
The GLK is the Mercedes SUV for buyers who value distinctive styling over modern blandness. The boxy shape, squared-off arches, and rugged stance have aged remarkably well. The M272/M276 petrol V6s are the engines that keep these cars on the road — simple, reliable, and with no DPF or AdBlue complexity. Buy a 2012+ facelift for the updated interior and M276 engine.
Real talk. The right GLK for you depends on your budget, your mileage, and your patience for maintenance. Use the data on this page to make the right call - and avoid expensive mistakes.
If your GLK diesel has a cold-start rattle on the OM651, or if you've spotted black tar around the injectors, you're facing the defining GLK diesel decision: repair the injector seals before they weld into the head, or replace the entire engine if it's too late.
The M272 petrol V6 is a different story — if it's running rough, camshaft adjuster wear is the most likely culprit, and it's a fixable problem. The economics answer depends entirely on your engine choice and vehicle value.
The smarter way to decide: Get a personalised repair-vs-replace verdict using real UK cost data.
Launch the BMW diagnostic calculator with GLK pre-selected.
We'll identify it first.
Identification is the first step inside the tool.
We'll pinpoint your exact engine code before running the diagnostics.
Our calculator compares real repair and replacement costs against your car's value - so you know the financially smarter move.
Built on Real Data - Every reliability rating and cost range on this page comes from 152+ real UK GLK engine enquiries in 2025 [MB-VERIFIED], not estimates or guesswork.
We Tell You When Not to Repair - If your pre-facelift GLK diesel needs a £4,800 OM651 replacement against a £4,000 car value, we'll tell you to scrap it. The 70% Mercedes threshold is applied honestly to every engine on this page. [MB-QUOTE]
Vetted Mercedes - Benz Specialists — Our network includes 25+ vetted Mercedes-Benz specialists who work on GLK engines daily — from OM651 chain assessment to M272 camshaft diagnosis, we know exactly who to send you to.
Part of Engine Finders - mercedesengine.uk is part of the Engine Finders family, the UK's leading engine replacement marketplace — giving you the research depth of an independent authority with a vetted route to action when you need one.
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