What are the common problems with the Mercedes-Benz GLC 250 and 300 petrol?

M274: thermostat housing failure (coolant loss, P0128/P0597), PCV system failure (rough idle, whistling, P052E), timing chain stretch (rattling on cold start), camshaft actuator wear, turbocharger failure at higher mileages. M264: camshaft centre valve filter issues, cooling system concerns. The M274's PCV system and timing chain are the most critical concerns.

Is it worth replacing a Mercedes-Benz GLC 250 / 300 petrol engine, or should I scrap the car?

GLC values remain strong — a well-kept X253 is often worth £12,000–£25,000+. A £3,000–£7,500 reconditioned engine is 15–40% of the vehicle's value — apply the Mercedes 70% scrap threshold. If the car is a cherished example with good bodywork, replacement is often worthwhile.

How do I find my Mercedes-Benz GLC 250 or 300 petrol engine code?

Listed on the VIN plate and vehicle documentation. X253 pre-facelift (2015–2019) uses M274; X253 facelift (2019–2022) uses M264. Tell us your registration date and we'll confirm it for free.

Can I repair the M274 timing chain, or does the engine need replacement?

The timing chain and tensioner can be replaced — they are wear items. Replacement costs £1,200–£2,500. The M274 uses a dual-row chain, which is more robust than the single-row M271, but it can still stretch, especially on neglected oil change intervals. If the chain fails and jumps timing, the engine is typically destroyed. A preventative chain replacement is far cheaper than a full engine replacement (£3,000+). At the first sign of rattling on cold start, book an inspection immediately.

Mercedes-Benz GLC 250 / 300 Petrol2015–20222 Engine Generations

Mercedes-Benz GLC 250 / 300 Petrol Engine Replacement — Compare Prices & Get Quotes

Name: Mercedes-Benz GLC 250 / 300 Petrol UK Engine Enquiry Data 2025
Creator: MercedesEngine.uk

The GLC 250 and 300 are powered by Mercedes' 2.0-litre turbocharged petrol engines — the M274 in pre-facelift cars and the M264 with EQ Boost in facelift models. Both are smooth and refined, but thermostat housing failures, timing chain stretch and PCV system issues are well-documented. Get quotes from UK specialists for reconditioned, rebuilt and used units today.

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Mercedes-Benz GLC 250 / 300 Petrol Engines — from £1,800 to £7,500Common codes: M274, M264

Mercedes-Benz GLC 250 / 300 Petrol Engines — from £1,800 to £7,500· Common codes: M274, M264

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The GLC 250 / 300 PETROL THROUGH TIME — Era Map

Four generations. Four eras. One guide to reliability, costs and what really matters.

GenerationYearsEngine CodeReliabilityRecon CostEra Note

Why use this era map?

Every cost guide, reliability rating and engine code on this page is aligned to the data above. This keeps everything consistent and trustworthy.

Real UK Cost Data

Verified Reliability

Expert Insights

Updated for 2025

Mercedes-Benz GLC 250 / 300 Petrol Engine Replacement Costs

Supply Only£3,000–£5,500

Fitted (Indie)£5,000–£7,500

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£1,800–£3,500£3,500–£5,5001–6 monthsBudget priority; older M274 examples

Reconditioned Engine£3,000–£5,500£5,000–£7,50012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£4,500–£7,500£6,500–£9,50012–24 monthsLong‑term ownership; 3+ year horizon

Main Dealer New£6,000–£10,000+£8,000–£12,000+24–36 monthsInsurance jobs, warranty claims

Figures above reflect the current GLC 250/300 petrol market. Reconditioned M264 engines start from around £3,495. M274 engines typically sit at the lower end of the range; M264 engines command a premium. Total installed cost for a reconditioned engine is typically around £1,800–£2,800.

Labour estimate: Fitting a GLC 250/300 petrol engine typically takes 10–14 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer). The engine bay is relatively accessible compared to V6 and V8 variants.

→ Compare GLC 250 / 300 petrol engine prices from UK specialists

Common Problems

1. Thermostat Housing Failure (M274 & M264)

Symptoms: Coolant loss with no visible external leak, rising temperature gauge, engine warning light (P0128, P0597), heater not working properly

Typical mileage: 40,000–80,000 miles

Repair cost: £400–£800 (thermostat housing replacement)

Replacement cost: N/A — repair only

🟠 Check - book inspection urgently

Our recommendation:

The thermostat housing is the most common problem on the M274 engine. It is prone to failure and coolant loss, which can lead to overheating if not addressed. The thermostat is electric and located under the engine, making replacement more labour-intensive than on older engines. If you notice coolant loss or a warning light, have the thermostat housing inspected immediately. Catching it early prevents more serious overheating damage.

Read the full thermostat failure guide

1. Thermostat Housing Failure (M274 & M264)

Symptoms: Coolant loss with no visible external leak, rising temperature gauge, engine warning light (P0128, P0597), heater not working properly

Typical mileage: 40,000–80,000 miles

Repair cost: £400–£800 (thermostat housing replacement)

Replacement cost: N/A — repair only

🟠 Check - book inspection urgently

Our recommendation:

Read the full thermostat failure guide

2. PCV System Failure (M274)

Symptoms: Rough idle, engine warning light, whistling noise from the engine, oil consumption, P052E code

Typical mileage: 50,000–100,000 miles

Repair cost: £500–£1,500 (PCV valve and crankcase breather replacement)

Replacement cost: N/A — repair only

🟠 Check - book inspection urgently

Our recommendation:

The M274 engine is "burdened with an expensive replacement of the PCV system failure". Repair costs can be significant — some owners report estimates exceeding $5,000 USD. The PCV system is integrated into the cylinder head, making replacement labour-intensive. If you experience rough idle, a whistling noise, or a P052E code, have the PCV system inspected promptly. Early intervention can prevent more serious oil consumption issues.

Read the full PCV failure guide

3. Timing Chain Stretch (M274)

Symptoms: Rattling noise on cold start, metallic ticking from the front of the engine, engine warning light, cam timing errors

Typical mileage: 60,000–100,000 miles

Repair cost: £1,200–£2,500 (timing chain, tensioner and guide replacement)

Replacement cost: £3,000–£5,500 (if chain jumps and causes valve interference)

🔴 Immediate - if the timing chain fails, the engine is typically destroyed

Our recommendation:

The M274's timing chain lifespan is approximately 80k miles (plus or minus 20k). Timing chain stretch is a known issue, particularly on neglected oil change intervals. The M274 uses a dual-row chain, which is more robust than the single-row M271, but it is not immune to wear. If you hear rattling on cold start, book an inspection immediately. A preventative chain replacement is far cheaper than a full engine replacement.

Read the full timing chain failure guide

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GLC 250 / 300 Petrol — Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

GLC 250 / 300 Petrol — Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

Can It Be Repaired?

ProblemRepairable?Typical CostWhen It Makes SenseThermostat housing failure✅ Yes£400–£800Well-understood job — catch before overheatingPCV system failure (M274)✅ Yes£500–£1,500Expensive but cheaper than a new engineTiming chain tensioner (preventative)✅ Yes£1,200–£2,500Labour-intensive but far cheaper than a full engine replacementTiming chain failure (engine damage)❌ Usually NoEngine replacementIf chain jumps and valves hit pistons, replacement is the only optionCamshaft actuator wear (M274)✅ Yes£800–£2,000Catch early; avoid camshaft damage

Buying This GLC 250 / 300 Petrol? Check These First

Buy If

Facelift X253 (2019+) with M264 engine — more modern with EQ Boost and improved efficiency
M274 car with evidence of thermostat housing and PCV system work — the common weaknesses addressed
Full service history with regular oil changes (every 10,000 miles) — timing chain health depends on it
Evidence of timing chain inspection or replacement — especially important on higher-mileage M274 cars

Avoid If

M274 with no proof of PCV system work — expensive replacement may be imminent
Any rattling on cold start — timing chain stretch is likely
M274 with coolant loss and no diagnosis — thermostat housing failure is common
Poor service history — the M274 and M264 are sensitive to oil quality

Closing Verdict

The GLC 250 and 300 petrols are powered by two generations of Mercedes 2.0-litre turbocharged four-cylinders. The M274 (2015–2019) is generally reliable but has known weaknesses: thermostat housing failure (the most common issue), PCV system failure (expensive to replace), timing chain stretch on neglected oil intervals, and camshaft actuator wear. The M264 (2019–2022) replaced the M274 with EQ Boost technology, offering improved efficiency but with reports of camshaft centre valve filter issues. Buy on history, maintain on schedule, and these engines will reward you with smooth, refined performance. Skip the history and it will punish you.

Don't guess.Get the right engine at the right price.

→ Compare GLC 250 / 300 petrol engine prices before you buy

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Buying Checklist

Before you buy a used Mercedes-Benz GLC 250 or 300 petrol (or before you commit to an engine replacement), check these:

1. Cold Start — Listen for rattles from the front of the engine (timing chain warning on M274)

2. Service History — including which generation (M274 or M264) and evidence of major maintenance

3. Thermostat/Coolant — Any coolant loss or thermostat warning lights? (the most common M274 issue)

4. PCV System (M274) — Any rough idle or whistling? (PCV failure is expensive to repair)

5. Engine Warning Light — Have codes been read? Any unresolved issues (P0128, P0597, P052E)?

6. Oil Level — Any excessive oil consumption? (PCV or piston ring issues)

7. Camshaft Actuators (M274) — Any noise on cold start? (wear is common after 60–70k miles)

8. MOT History — Check for emissions-related failures (catalyst, O2 sensors)

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 320d pitfalls.

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 320d pitfalls.

Engine Codes

This table's rows match Section 1B's Era Map exactly — two engine families across the GLC 250/300 petrol's history.

M274 (DE20 LA)

Years2015–2019

Power211 hp

2025 Enquiries[PATTERN DATA]

Avg. Recon Cost£3,000–£5,500 [MB-QUOTE]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

M274 (DE20 LA)2015–2019211 hp[PATTERN DATA]£3,000–£5,500 [MB-QUOTE]

M264 (DE20 LA)2019–2022258 hp[PATTERN DATA]£3,500–£7,500 [MB-QUOTE]

Technical Specs

M264 — GLC 300

Displacement1,991cc (2.0‑litre)

Cylinders4-cylinder inline

Bore x Stroke83 mm x 92 mm

Compression Ratio~9.8:1

Fuel SystemDirect injection with piezo injectors

TurbochargerTwin-scroll turbocharger

ValvetrainDOHC, 4 valves per cylinder, dual-row timing chain

Displacement1,991cc (2.0‑litre)

Cylinders4-cylinder inline

Fuel SystemDirect injection

TurbochargerTwin-scroll turbocharger

MHEV48V EQ Boost integrated starter-generator

→ Compare GLC 250 / 300 petrol engine prices for your Mercedes

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Market Intelligence

Most Common Failure

M274: Thermostat housing failure and PCV system failure / M264: Camshaft centre valve filter issues — the defining risks of each generation

Average Enquiry Mileage

M274: 50,000–90,000 miles / M264: 30,000–60,000 miles【PATTERN DATA】

Average Replacement Cost

M274: £3,000–£5,500 / M264: £3,500–£7,500 reconditioned, supply only【MB-QUOTE】

Most Requested Engine Code

M274 — the most common GLC petrol engine【PATTERN DATA】

Peak Enquiry Season

Autumn — pre‑winter vehicle preparation【PATTERN DATA】

Regional Demand

London20%

South East18%

South West (14%)【PATTERN DATA】

Regional Demand Breakdown

20%London

18%South East

Frequently Asked Questions

All prices are indicative UK market ranges based on historical quote data from our network of engine specialists. Actual costs vary by variant, engine code, damage severity and workshop location. Use our free comparison tool to get tailored quotes. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty — always confirm terms with your chosen supplier.

Trusted GLC Petrol Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real GLC 250 and 300 petrol owners, as part of the Engine Finders network, across both the M274 and M264 generations — no matter which GLC era you drive.
Compare GLC 250 / 300 Petrol Engine Replacement Companies
see prices, warranty terms and supply & fit options side‑by‑side before you commit, with specialists who genuinely understand the M274's thermostat housing, PCV system, timing chain and camshaft actuator nuances, and the M264's EQ Boost and camshaft centre valve complexities.
UK Engine Replacement Services for GLC 250 / 300 Petrol
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Find the best Mercedes-Benz GLC 250 or 300 petrol engine replacement UK drivers rely on. Compare prices from trusted specialists on MercedesEngine.uk today and keep your GLC performing at its best.

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