Mercedes-Benz GLK X204
Weaknesses, engine ratings and buying advice
The GLK was Mercedes' answer to the BMW X3 and Audi Q5 — angular design, solid engineering, and the last compact Mercedes SUV with a rear-drive-based platform. A sleeper on the used market because it lives in the GLC successor's shadow.
The engine range is broad: petrols include the M274 1.6–2.0L turbo (135–155 kW) in GLK 200 and GLK 250, the M272 V6 3.0–3.5L (170–200 kW) in early models, and the M276 V6 3.5L (225 kW) in the GLK 350. The M274 is the most modern but has timing chain concerns too. The V6 engines M272 and M276 are refined and long-lasting — watch for the M272's balance shaft sprocket issue (known first-gen problem).
Diesels are dominated by the OM651DE22 2.1L (105–150 kW) — the workhorse of the range. GLK 200 CDI through GLK 250 CDI cover most of the market. The V6 diesel OM642 3.0L (150–195 kW) in the GLK 300 CDI and GLK 350 CDI offers commanding performance, but the OM642's oil cooler seal is a known and expensive problem ($2,200–3,300). Black oil sludge in the coolant is the alarm signal.
The 7G-Tronic automatic (7-speed torque converter) is robust and comfortable — significantly better than the compact class DCT variants. The rear axle uses a sophisticated multi-link setup that needs bushings and control arms past 75,000 miles.
Rust is moderate on the GLK — the underbody is well-protected, but rear wheel arches can show early signs on older examples. Parktronic sensors tend to fail after 8 years.
Test-drive checklist: OM642 diesel: open the oil cap and check for milky residue (oil cooler seal). OM651: cold-start rattle = timing chain. Automatic must shift smoothly without jerking. Test rear axle for clunking over cobblestones.
2026 market: Between $11,000 and $24,200 for examples with 50,000–90,000 miles. The GLK 250 CDI 4MATIC is most sought-after.
Insider pick: GLK 250 CDI (OM651DE22, 150 kW) 4MATIC — enough diesel torque, solid AWD, and cheaper than an equivalent-age GLC.
306 PS
GLK 350 · Benzin
V6 in the Compact SUV — Solid Power Without Drama
Decent190–265 PS
3.0L V6 Diesel Diesel
7 weaknesses
Stay Away!Engine Overview
The Mercedes-Benz GLK X204 is available with 10 engine variants — from 120 to 435 hp. 1 variants had engine changes — the model year is crucial.
V6 CDI with common rail and piezo injectors. Powerful, refined and torquey. The most expensive weak point is the oil cooler in the engine V: ageing seals cause oil and coolant loss; repair often exceeds €2,000 due to the labour-intensive teardown. Plastic swirl flap linkages break from soot deposits and can fall into the intake tract. Piezo injectors lose their seal through heat: diesel enters the oil and thins it, risking bearing damage. VGT actuator linkage jams from soot accumulation, triggering limp mode. Glow plugs corrode and snap off during removal. The standard oil pump delivers insufficient pressure at high load — an upgrade pump is recommended from 150,000 km.
- !! Oil Cooler Gaskets Leaking — Oil and Coolant Loss from 120,000 km
The best-known problem of the OM642: the oil cooler gaskets in the V-section of the engine fail. Oil leaks into the coolant or externally. Particularly prone on vehicles built up to 2009.
Symptoms: Oil loss warning, oil spots under the left side of the vehicle, oil streaks visible on the belt tensioner - !! Swirl Flap Linkage Breaks — Plastic Joint Fails from 100,000 km
The plastic linkages of the swirl flaps in the OM642 intake manifold break. Aluminium repair kits are available and more durable. In the event of complete failure there is a risk of debris entering the engine.
Symptoms: Engine warning light, fault codes for intake flap/swirl flap, power loss particularly at low rpm - !! Injector Seal Leaking — Soot Deposits and Diesel in Oil from 120,000 km
Piezo injectors seal poorly from heat, diesel enters the engine oil. Oil loses lubrication properties, tar-like residue around injectors is the typical telltale sign.
Symptoms: Rough idle, increased fuel consumption, knocking noises, oil level rising due to diesel contamination, engine oil smells of diesel
+ 4 more engine weaknesses + vehicle weaknesses
Most widespread Mercedes four-cylinder diesel, aluminium block with steel liners. Simplex timing chain sits at the rear of the gearbox and stretches from 120,000 km — chain tensioner recall covered 100,000+ vehicles in Germany (February–November 2014 production). Engine was part of the Mercedes emissions scandal: illegal thermal window defeat device; recall software in some vehicles actually worsened NOx values. Piezo injectors in the 250 CDI were never updated — remains an ongoing risk. Well-maintained examples with solenoid injectors and short oil-change intervals can reach 400,000 km.
- !! Chain Tensioner Seal Leaking — Recall
Over 100,000 vehicles recalled: the chain tensioner seal leaks, allowing engine oil to drip onto the exhaust system and potentially ignite.
Symptoms: Dropping oil level, oil smell from engine bay, oily deposits under the vehicle, possible oil fire - !! Timing Chain Stretch (Simplex Chain) from 150,000 km
The OM651 uses a simplex timing chain. With short-trip driving and overdue oil change intervals the chain stretches.
Symptoms: Light rattling noise on cold start from the rear of the engine, no fault code stored - !! Piezo Injector Faults from 80,000 km
Same Delphi piezo injector problems as in the DE18: 220 CDI and 250 CDI variants affected. Mercedes replaced them with solenoid injectors as part of a service action.
Symptoms: Vibrations and rough running especially under acceleration, elevated fuel consumption
+ 4 more engine weaknesses + vehicle weaknesses
Most widespread Mercedes four-cylinder diesel, aluminium block with steel liners. Simplex timing chain sits at the rear of the gearbox and stretches from 120,000 km — chain tensioner recall covered 100,000+ vehicles in Germany (February–November 2014 production). Engine was part of the Mercedes emissions scandal: illegal thermal window defeat device; recall software in some vehicles actually worsened NOx values. Piezo injectors in the 250 CDI were never updated — remains an ongoing risk. Well-maintained examples with solenoid injectors and short oil-change intervals can reach 400,000 km.
- !! Chain Tensioner Seal Leaking — Recall
Over 100,000 vehicles recalled: the chain tensioner seal leaks, allowing engine oil to drip onto the exhaust system and potentially ignite.
Symptoms: Dropping oil level, oil smell from engine bay, oily deposits under the vehicle, possible oil fire - !! Timing Chain Stretch (Simplex Chain) from 150,000 km
The OM651 uses a simplex timing chain. With short-trip driving and overdue oil change intervals the chain stretches.
Symptoms: Light rattling noise on cold start from the rear of the engine, no fault code stored - !! Piezo Injector Faults from 80,000 km
Same Delphi piezo injector problems as in the DE18: 220 CDI and 250 CDI variants affected. Mercedes replaced them with solenoid injectors as part of a service action.
Symptoms: Vibrations and rough running especially under acceleration, elevated fuel consumption
+ 4 more engine weaknesses + vehicle weaknesses
Most widespread Mercedes four-cylinder diesel, aluminium block with steel liners. Simplex timing chain sits at the rear of the gearbox and stretches from 120,000 km — chain tensioner recall covered 100,000+ vehicles in Germany (February–November 2014 production). Engine was part of the Mercedes emissions scandal: illegal thermal window defeat device; recall software in some vehicles actually worsened NOx values. Piezo injectors in the 250 CDI were never updated — remains an ongoing risk. Well-maintained examples with solenoid injectors and short oil-change intervals can reach 400,000 km.
- !! Chain Tensioner Seal Leaking — Recall
Over 100,000 vehicles recalled: the chain tensioner seal leaks, allowing engine oil to drip onto the exhaust system and potentially ignite.
Symptoms: Dropping oil level, oil smell from engine bay, oily deposits under the vehicle, possible oil fire - !! Timing Chain Stretch (Simplex Chain) from 150,000 km
The OM651 uses a simplex timing chain. With short-trip driving and overdue oil change intervals the chain stretches.
Symptoms: Light rattling noise on cold start from the rear of the engine, no fault code stored - !! Piezo Injector Faults from 80,000 km
Same Delphi piezo injector problems as in the DE18: 220 CDI and 250 CDI variants affected. Mercedes replaced them with solenoid injectors as part of a service action.
Symptoms: Vibrations and rough running especially under acceleration, elevated fuel consumption
+ 4 more engine weaknesses + vehicle weaknesses
V6 CDI with common rail and piezo injectors. Powerful, refined and torquey. The most expensive weak point is the oil cooler in the engine V: ageing seals cause oil and coolant loss; repair often exceeds €2,000 due to the labour-intensive teardown. Plastic swirl flap linkages break from soot deposits and can fall into the intake tract. Piezo injectors lose their seal through heat: diesel enters the oil and thins it, risking bearing damage. VGT actuator linkage jams from soot accumulation, triggering limp mode. Glow plugs corrode and snap off during removal. The standard oil pump delivers insufficient pressure at high load — an upgrade pump is recommended from 150,000 km.
- !! Oil Cooler Gaskets Leaking — Oil and Coolant Loss from 120,000 km
The best-known problem of the OM642: the oil cooler gaskets in the V-section of the engine fail. Oil leaks into the coolant or externally. Particularly prone on vehicles built up to 2009.
Symptoms: Oil loss warning, oil spots under the left side of the vehicle, oil streaks visible on the belt tensioner - !! Swirl Flap Linkage Breaks — Plastic Joint Fails from 100,000 km
The plastic linkages of the swirl flaps in the OM642 intake manifold break. Aluminium repair kits are available and more durable. In the event of complete failure there is a risk of debris entering the engine.
Symptoms: Engine warning light, fault codes for intake flap/swirl flap, power loss particularly at low rpm - !! Injector Seal Leaking — Soot Deposits and Diesel in Oil from 120,000 km
Piezo injectors seal poorly from heat, diesel enters the engine oil. Oil loses lubrication properties, tar-like residue around injectors is the typical telltale sign.
Symptoms: Rough idle, increased fuel consumption, knocking noises, oil level rising due to diesel contamination, engine oil smells of diesel
+ 4 more engine weaknesses + vehicle weaknesses
V6 CDI with common rail and piezo injectors. Powerful, refined and torquey. The most expensive weak point is the oil cooler in the engine V: ageing seals cause oil and coolant loss; repair often exceeds €2,000 due to the labour-intensive teardown. Plastic swirl flap linkages break from soot deposits and can fall into the intake tract. Piezo injectors lose their seal through heat: diesel enters the oil and thins it, risking bearing damage. VGT actuator linkage jams from soot accumulation, triggering limp mode. Glow plugs corrode and snap off during removal. The standard oil pump delivers insufficient pressure at high load — an upgrade pump is recommended from 150,000 km.
- !! Oil Cooler Gaskets Leaking — Oil and Coolant Loss from 120,000 km
The best-known problem of the OM642: the oil cooler gaskets in the V-section of the engine fail. Oil leaks into the coolant or externally. Particularly prone on vehicles built up to 2009.
Symptoms: Oil loss warning, oil spots under the left side of the vehicle, oil streaks visible on the belt tensioner - !! Swirl Flap Linkage Breaks — Plastic Joint Fails from 100,000 km
The plastic linkages of the swirl flaps in the OM642 intake manifold break. Aluminium repair kits are available and more durable. In the event of complete failure there is a risk of debris entering the engine.
Symptoms: Engine warning light, fault codes for intake flap/swirl flap, power loss particularly at low rpm - !! Injector Seal Leaking — Soot Deposits and Diesel in Oil from 120,000 km
Piezo injectors seal poorly from heat, diesel enters the engine oil. Oil loses lubrication properties, tar-like residue around injectors is the typical telltale sign.
Symptoms: Rough idle, increased fuel consumption, knocking noises, oil level rising due to diesel contamination, engine oil smells of diesel
+ 4 more engine weaknesses + vehicle weaknesses
Four-valve V6 with variable valve timing. Known for the balance shaft sprocket issue on 2004–2008 production (engine serial below 2729..30 468993). The soft composite sprocket wears progressively; timing chain loses tension and the right camshaft bank retards. Fault codes P0016/P0017 and cold-start rattling are the first signs — ignoring them leads to catastrophic engine damage. Repair cost approx. €2,500–4,000 (requires engine removal). From the above serial number onward, hardened steel sprockets were fitted — failure excluded. Also check camshaft adjuster solenoids for oil in wiring harness. Oil changes every 10,000 km with MB 229.5.
- !! Balance Shaft Sprocket Wears Prematurely from 140,000 km
The plastic balance shaft sprocket on the M272 wears prematurely from the timing chain. The right cylinder bank goes out of timing. Affected up to end of October 2006.
Symptoms: Fault codes P0016/P0017 (camshaft right bank), chain rattling, rough running at idle, in extreme cases engine damage - !! Timing Chain Stretches and Damages Timing from 120,000 km
Alongside the balance shaft issue the M272 shows premature timing chain stretch. Chain wear on softer sprockets leads to timing deviations.
Symptoms: Chain noise especially on cold start, camshaft fault codes, rough running, engine irregularities - !! Camshaft Adjuster Leaks — Wiring Harness Contaminated from 90,000 km
Four camshaft adjuster solenoids (two per cylinder bank) develop leaks; oil creeps into the wiring harness as far as the ECU. Repair costs up to €1,700 documented.
Symptoms: CEL, oil traces at camshaft connectors, lambda sensor failure due to oil contamination, non-specific faults that recur
+ 3 more engine weaknesses + vehicle weaknesses
Evolved four-cylinder turbo with direct injection and piezo injectors. Significantly less prone to timing chain problems than the M271, but not immune. Electric thermostat tends to fail early — always replace as complete OEM unit. Early DE20 LA units (2015–2016) have a piston pin manufacturing tolerance issue — short block replacement required if symptom arises. Camshaft solenoids (Y49/1, Y49/2, pre-2014) prone to leaks. Oil changes every 10,000 km with MB 229.5 recommended.
- !! High-Pressure Pump Faulty or Noisy from 120,000 km
The high-pressure fuel pump on the M274 is driven by a lobe on the intake camshaft. Wear on the drive lobe or pump follower leads to pressure drop.
Symptoms: Metallic ticking from engine area, starting problems or extended cranking, power loss, fault code P0087 - !! Camshaft Adjuster Leaks — Oil in Wiring Harness from 100,000 km
On the M274 too, the camshaft adjuster solenoids develop leaks. Oil penetrates the wiring harness by capillary action and can damage the engine ECU.
Symptoms: Fault code P0010, CEL, oil traces at camshaft connectors, lambda sensor failure, in severe cases ECU failure - !! Piston Pin Knock (2015–2016 units) from 60,000 km
Early M274 DE20 LA units (2015–2016) have a manufacturing tolerance issue with excessive piston pin clearance. Blue smoke and oil consumption up to requiring short-block replacement.
Symptoms: Metallic knocking from engine block, blue-grey exhaust smoke, increased oil consumption
+ 4 more engine weaknesses + vehicle weaknesses
Evolved four-cylinder turbo with direct injection and piezo injectors. Significantly less prone to timing chain problems than the M271, but not immune. Electric thermostat tends to fail early — always replace as complete OEM unit. Early DE20 LA units (2015–2016) have a piston pin manufacturing tolerance issue — short block replacement required if symptom arises. Camshaft solenoids (Y49/1, Y49/2, pre-2014) prone to leaks. Oil changes every 10,000 km with MB 229.5 recommended.
- !! High-Pressure Pump Faulty or Noisy from 120,000 km
The high-pressure fuel pump on the M274 is driven by a lobe on the intake camshaft. Wear on the drive lobe or pump follower leads to pressure drop.
Symptoms: Metallic ticking from engine area, starting problems or extended cranking, power loss, fault code P0087 - !! Camshaft Adjuster Leaks — Oil in Wiring Harness from 100,000 km
On the M274 too, the camshaft adjuster solenoids develop leaks. Oil penetrates the wiring harness by capillary action and can damage the engine ECU.
Symptoms: Fault code P0010, CEL, oil traces at camshaft connectors, lambda sensor failure, in severe cases ECU failure - !! Piston Pin Knock (2015–2016 units) from 60,000 km
Early M274 DE20 LA units (2015–2016) have a manufacturing tolerance issue with excessive piston pin clearance. Blue smoke and oil consumption up to requiring short-block replacement.
Symptoms: Metallic knocking from engine block, blue-grey exhaust smoke, increased oil consumption
+ 4 more engine weaknesses + vehicle weaknesses
Four-valve V6 with variable valve timing. Known for the balance shaft sprocket issue on 2004–2008 production (engine serial below 2729..30 468993). The soft composite sprocket wears progressively; timing chain loses tension and the right camshaft bank retards. Fault codes P0016/P0017 and cold-start rattling are the first signs — ignoring them leads to catastrophic engine damage. Repair cost approx. €2,500–4,000 (requires engine removal). From the above serial number onward, hardened steel sprockets were fitted — failure excluded. Also check camshaft adjuster solenoids for oil in wiring harness. Oil changes every 10,000 km with MB 229.5.
- !! Balance Shaft Sprocket Wears Prematurely from 140,000 km
The plastic balance shaft sprocket on the M272 wears prematurely from the timing chain. The right cylinder bank goes out of timing. Affected up to end of October 2006.
Symptoms: Fault codes P0016/P0017 (camshaft right bank), chain rattling, rough running at idle, in extreme cases engine damage - !! Timing Chain Stretches and Damages Timing from 120,000 km
Alongside the balance shaft issue the M272 shows premature timing chain stretch. Chain wear on softer sprockets leads to timing deviations.
Symptoms: Chain noise especially on cold start, camshaft fault codes, rough running, engine irregularities - !! Camshaft Adjuster Leaks — Wiring Harness Contaminated from 90,000 km
Four camshaft adjuster solenoids (two per cylinder bank) develop leaks; oil creeps into the wiring harness as far as the ECU. Repair costs up to €1,700 documented.
Symptoms: CEL, oil traces at camshaft connectors, lambda sensor failure due to oil contamination, non-specific faults that recur
+ 3 more engine weaknesses + vehicle weaknesses
Four-valve V6 in two basic variants: 3.5L naturally aspirated (DES 35, 185–225 kW) with direct injection and stratified charge — refined, linear, no classic naturally aspirated feel. And the 3.0L BiTurbo family (DEH 30 LA, 245–295 kW) with Nanoslide coating, twin turbochargers and water-air charge air cooler. The BiTurbo sings sonorously from 2,500 rpm and screams at the top — exceptional for a V6. Weak points: timing chain wears early when oil change intervals are pushed. Oil cooler in the V-block doesn't seal forever. Camshaft solenoids leak. On the 3.5L stratified-charge variant add NOx sensor failures from short-trip use. Early DES 35 (2011–2013) had piston slap issues. The BiTurbo unit with Nanoslide is considered more robust. Maintained with short oil change intervals (10,000–12,000 km) the engine easily lasts beyond 200,000 km.
- !! Oil cooler leaking in the V-block from 120,000 km
Known weak point: the oil cooler gasket in the V-block of the M276 ages and starts leaking. Repair is extremely labour-intensive because the engine must be partially disassembled — cost €1,700–3,800.
Symptoms: Oil spots under the vehicle, rainbow sheen on wet road, dropping oil level, oil smell - !! Camshaft adjuster leaking — wiring harness contaminated from 100,000 km
Known damage pattern on all newer Mercedes engines: solenoid valves leak, oil migrates into the wiring harness. First the lambda sensors die, then the ECU. Repair documented up to €1,970.
Symptoms: Check engine light with camshaft fault code, lambda sensor failure, oil film on connectors, in extreme cases ECU failure - !! Piston slap (early 3.5L variants) from 150,000 km
On early M276 DES 35 (build years 2011–2013) pistons can loosen due to cylinder bore wear. Knock noise on cold start, worst case engine damage.
Symptoms: Clacking and knocking on cold start from the engine area, getting louder over time, rough idle when cold
+ 7 more engine weaknesses + vehicle weaknesses
Vehicle Weaknesses
| Weakness | Cost | |
|---|---|---|
| OM642 Diesel Oil Cooler Leaks at High Mileage OM642 diesel oil cooler tends to develop leaks at high mileage. Oil traces under the gearbox are a warning sign. Repair requires 7 hours of labour through complete disassembly. Symptoms: Oil spots under the engine, oil loss without visible leak on top, engine oil level drops from 150,000 km | High |
Test Reports
TÜV Report 2017
Overall winner of the TÜV Report 2017 — the compact SUV was among the least fault-prone vehicles of its time.
2016-11ADAC Breakdown Statistics 2023
The compact SUV also shows very good reliability values in the breakdown statistics.
2023-04Top Reported Issues
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Known Problems and Issues +
A total of 46 weaknesses have been documented for the Mercedes-Benz GLK X204 (2008–2015) — 37 engine-related and 9 vehicle-related. 3 problem engines: OM651DE22 (2.1L Diesel), M272 (3.0-3.5L V6), OM642 (3.0L V6 Diesel). Typical issues affect Cooling, Electronics, Brakes, Suspension.
GLK (OM651DE22, 2008–2015) — Stay Away!: Chain Tensioner Seal Leaking — Recall, Timing Chain Stretch (Simplex Chain), Piezo Injector Faults. Power: 163–170 PS.
GLK (OM642, 2008–2012) — Stay Away!: Oil Cooler Gaskets Leaking — Oil and Coolant Loss, Swirl Flap Linkage Breaks — Plastic Joint Fails, Injector Seal Leaking — Soot Deposits and Diesel in Oil. Power: 224–231 PS.
GLK (OM651DE22, 2009–2015) — Stay Away!: Chain Tensioner Seal Leaking — Recall, Timing Chain Stretch (Simplex Chain), Piezo Injector Faults. Power: 204 PS.
GLK (OM651DE22, 2010–2015) — Stay Away!: Chain Tensioner Seal Leaking — Recall, Timing Chain Stretch (Simplex Chain), Piezo Injector Faults. Power: 136–143 PS.
GLK (OM642, 2010–2015) — Stay Away!: Oil Cooler Gaskets Leaking — Oil and Coolant Loss, Swirl Flap Linkage Breaks — Plastic Joint Fails, Injector Seal Leaking — Soot Deposits and Diesel in Oil. Power: 204–211 PS.
GLK (OM642, 2012–2015) — Stay Away!: Oil Cooler Gaskets Leaking — Oil and Coolant Loss, Swirl Flap Linkage Breaks — Plastic Joint Fails, Injector Seal Leaking — Soot Deposits and Diesel in Oil. Power: 265 PS.
GLK (M272, 2008–2012) — Stay Away!: Balance Shaft Sprocket Wears Prematurely, Timing Chain Stretches and Damages Timing, Camshaft Adjuster Leaks — Wiring Harness Contaminated. Power: 231 PS.
GLK (M272, 2008–2012) — Stay Away!: Balance Shaft Sprocket Wears Prematurely, Timing Chain Stretches and Damages Timing, Camshaft Adjuster Leaks — Wiring Harness Contaminated. Power: 272 PS.
GLK (M276, 2012–2015) — Be Careful: Oil cooler leaking in the V-block, Camshaft adjuster leaking — wiring harness contaminated, Piston slap (early 3.5L variants). Power: 306 PS.
GLK (M274, 2013–2015) — Be Careful: High-Pressure Pump Faulty or Noisy, Camshaft Adjuster Leaks — Oil in Wiring Harness, Piston Pin Knock (2015–2016 units). Power: 184 PS.
GLK (M274, 2013–2015) — Be Careful: High-Pressure Pump Faulty or Noisy, Camshaft Adjuster Leaks — Oil in Wiring Harness, Piston Pin Knock (2015–2016 units). Power: 211 PS.
What to watch out for with the Mercedes-Benz GLK? See the detailed listing of all engine and vehicle weaknesses in the sections above.
Frequently Asked Questions
What problems and weaknesses does the Mercedes-Benz GLK X204 have? +
What should I look for when buying a used Mercedes-Benz GLK X204? +
Which engine is recommended? +
Which Mercedes-Benz GLK X204 engine is the most fun? +
Is the Mercedes-Benz GLK X204 worth buying used? +
What horsepower variants are available for the Mercedes-Benz GLK X204? +
Last updated: February 2026 · All information without guarantee