Is the Mercedes-Benz R350 / R500 petrol engine reliable?

It depends entirely on which engine. The M113 V8 (2006–2010) is widely regarded as 'one of the most reliable engines I've ever encountered'. The M272 V6 (2006–2010) is the least reliable — balance shaft failure is a class-action-level issue. The M273 V8 (2010–2013) is more powerful but shares the M272's balance shaft/idler gear concerns. Buy the M113 if you can.

What are the common problems with the Mercedes-Benz R350 and R500 petrol?

M272: balance shaft failure (soft metal sprocket wears, causing timing issues — P0016–P0019 codes), rough running. M113: oil leaks (valve stem seals, oil pickup O-ring, coolant O-rings), intake manifold flap failure (P2005). M273: balance shaft/idler gear wear (same issue as M272). All models: 7G-Tronic transmission valve body failure.

Is it worth replacing a Mercedes-Benz R350 / R500 petrol engine, or should I scrap the car?

R-Class values range from £3,000–£12,000 depending on condition and spec. A £2,500–£7,500 reconditioned engine is 25–50% 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. On a tired example with multiple other issues (Airmatic, transmission), get a scrap valuation first.

How do I find my Mercedes-Benz R350 or R500 petrol engine code?

Listed on the VIN plate and vehicle documentation. W251 R350 (2006–2010) uses M272; W251 R500 (2006–2010) uses M113; W251 R500 (2010–2013) uses M273. Tell us your registration date and we'll confirm it for free.

Can I repair the M272 balance shaft, or does the engine need replacement?

The balance shaft can be replaced — it's a known weak point. Replacement costs £5,000–£7,000. If the balance shaft fails and timing is thrown off, the engine can be destroyed. A preventative balance shaft replacement with the updated timing gear is far cheaper than a full engine replacement (£2,500+). At the first sign of rattling or check engine light (P0016–P0019) on a pre-2010 R350, book an inspection immediately.

Mercedes-Benz R350 / R500 Petrol2006–20132 Engine Families

Mercedes-Benz R350 / R500 Petrol Engine Replacement — Compare Prices & Get Quotes

Name: Mercedes-Benz R350 / R500 Petrol UK Engine Enquiry Data 2025
Creator: MercedesEngine.uk

The R350 and R500 are powered by Mercedes' smoothest petrol V6 and V8 engines — the M272 in the R350 and the M113/M273 in the R500. They're refined and torquey, but balance shaft failure, oil leaks and intake manifold issues are well-documented. Get quotes from UK specialists for reconditioned, rebuilt and used units today.

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Mercedes-Benz R350 / R500 Petrol Engines — from £1,500 to £7,500Common codes: M272, M113, M273

Mercedes-Benz R350 / R500 Petrol Engines — from £1,500 to £7,500· Common codes: M272, M113, M273

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The R350 / R500 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 R350 / R500 Petrol Engine Replacement Costs

Supply Only£2,500–£5,500

Fitted (Indie)£4,500–£7,500

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£1,500–£3,500£3,000–£5,5001–6 monthsBudget priority; older M272 or M113 examples

Reconditioned Engine£2,500–£5,500£4,500–£7,50012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£4,500–£7,500£6,500–£10,00012–24 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 R-Class petrol market. Balance shaft repairs on the M272 typically cost $8,000 (£6,000+). The M113 is the most affordable V8 option; the M273 commands a premium. Reconditioned engines from specialist suppliers start from around £2,500 supply only.

Labour estimate: Fitting an R-Class petrol engine typically takes 12–16 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer). The longitudinal V6/V8 layout makes access relatively straightforward compared to transverse layouts.

→ Compare R350 / R500 petrol engine prices from UK specialists

Common Problems

1. M272 Balance Shaft Failure (R350 — 2006–2010)

Symptoms: Engine rattle or ticking noise from the front of the engine, check engine light (P0016, P0017, P0018, P0019), rough idling, stalling, rough running

Typical mileage: 60,000–100,000 miles

Repair cost: £5,000–£7,000 (balance shaft, timing chain and guide replacement)

Replacement cost: £2,500–£5,000 (if balance shaft failure destroys the engine)

🔴 Immediate - this is the single biggest risk on the M272 V6

Our recommendation:

The M272's balance shaft sprocket was made from soft metal that wears prematurely, causing timing to be thrown off. A class action lawsuit was filed over this issue. It's been said that "ALL will eventually fail". The repair costs are "huge, $8,000". If you're buying a pre-2010 R350, check the engine number — later engines were revised. If you hear any rattling or see check engine lights (P0016–P0019), book an inspection immediately. A preventative balance shaft replacement is far cheaper than a full engine replacement.

Read the full balance shaft failure guide

1. M272 Balance Shaft Failure (R350 — 2006–2010)

Symptoms: Engine rattle or ticking noise from the front of the engine, check engine light (P0016, P0017, P0018, P0019), rough idling, stalling, rough running

Typical mileage: 60,000–100,000 miles

Repair cost: £5,000–£7,000 (balance shaft, timing chain and guide replacement)

Replacement cost: £2,500–£5,000 (if balance shaft failure destroys the engine)

🔴 Immediate - this is the single biggest risk on the M272 V6

Our recommendation:

Read the full balance shaft failure guide

2. M113 Oil Leaks — Valve Stem Seals, Oil Pickup O-Ring, Coolant O-Rings (R500 — 2006–2010)

Symptoms: Oil spots under the car, burning oil smell, excessive oil consumption, coolant loss, engine knocking, eventual engine failure

Typical mileage: 70,000–120,000 miles

Repair cost: £1,500–£4,000 (seal replacement — valve stem seals, oil pickup O-ring, coolant O-rings)

Replacement cost: £3,000–£5,500 (if oil starvation destroys the engine)

🟠 Check - book inspection urgently

Our recommendation:

Despite the M113 being "one of the most reliable engines I've ever encountered", all of the seals are bad on these engines — valve stem seals, oil pickup O-ring, and front cover coolant O-rings. The oil pickup O-ring is a "single point of failure" that can destroy the engine if it fails. If your M113 is older, replace this O-ring preventatively. The rear main seal is also prone to failure. Check for oil spots regularly and investigate any unexplained oil consumption.

Read the full oil leak guide

3. M113 Intake Manifold Flap Failure (R500 — 2006–2010)

Symptoms: Check engine light (P2005), loss of power, rough idle, poor fuel economy, intake manifold rattle

Typical mileage: 60,000–120,000 miles

Repair cost: £500–£1,200 (intake manifold flap repair or replacement)

Replacement cost: N/A — repair only

🟡 Monitor - book inspection soon

Our recommendation:

The M113's intake manifold has plastic flaps and actuator arms that can break. The common issue is that the intake manifold gums up with oil via the PCV system, causing the flaps to become sticky and the arms to break. Kits are available to fix this, but you also need to address the PCV system. If you see a P2005 code, have the intake manifold inspected.

Read the full intake manifold failure guide

4. M273 Balance Shaft/Idler Gear Issues (R500 — 2010–2013)

Symptoms: Engine rattle on cold start, check engine light, camshaft correlation codes, rough running

Typical mileage: 60,000–100,000 miles

Repair cost: £2,500–£5,000 (idler gear and timing chain replacement)

Replacement cost: £3,500–£7,500 (if failure destroys the engine)

🔴 Immediate - early M273 engines share the M272's balance shaft/idler gear issues

Our recommendation:

The M273 V8 "will have the same problems with the cam shafts, causing repair costs to about $6,000 when about 100,000k is reached". The idler gear (which powers camshaft timing in the V8) suffers from the same soft metal issue as the M272's balance shaft. If you hear rattling on cold start, book an inspection immediately.

Read the full timing chain failure guide

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R350 / R500 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.

R350 / R500 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 SenseM272 balance shaft failure (pre-2010)✅ Yes£5,000–£7,000Labour-intensive but cheaper than a new engineM113 oil leaks (seals, O-rings)✅ Yes£1,500–£4,000Labour-intensive but well-understood; prevent oil starvationM113 intake manifold flap failure✅ Yes£500–£1,200Repair or replace manifold — catch before further damageM273 balance shaft/idler gear wear✅ Yes£2,500–£5,000Labour-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 optionTransmission valve body failure✅ Yes£2,000–£3,000Known issue on all R-Class models

Buying This R350 / R500 Petrol? Check These First

Buy If

R500 with the M113 V8 (2006–2010) — widely regarded as one of Mercedes' most reliable engines
R350 with revised balance shaft (later production) — the defining weakness addressed
Evidence of oil seal replacement on M113 (valve stem seals, oil pickup O-ring) — the most important maintenance on the V8
Full service history with regular oil changes (every 10,000 miles) — all three engines reward good maintenance
Post-2010 R500 with documented timing chain/idler gear work — the M273's weakness addressed

Avoid If

Pre-2010 R350 with no proof of balance shaft work — you're buying a known risk
R350 with rattling or check engine light (P0016–P0019) — balance shaft failure is imminent
R500 M113 with oil leaks and no service history — seals are failing
R500 M273 with no proof of timing chain work — the M273 shares the M272's issues
Poor service history — all three engines are unforgiving of neglect

Closing Verdict

The R-Class petrols are powered by three very different engines. The M272 V6 (2006–2010) is the most problematic — balance shaft failure is a class-action-level issue. The M113 V8 (2006–2010) is widely regarded as one of Mercedes' most reliable engines, but oil seals and intake manifold flaps are well-known weaknesses. The M273 V8 (2010–2013) is more powerful but shares the M272's balance shaft/idler gear concerns. Buy the M113 if you can — it's the most reliable of the three. Buy on history, maintain on schedule, and the R-Class will reward you with effortless cruising.

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

→ Compare R350 / R500 petrol engine prices before you buy

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Buying Checklist

Before you buy a used Mercedes-Benz R350 or R500 petrol (or before you commit to an engine replacement), check these:

1. Cold Start — Listen for rattling from the front of the engine (balance shaft/idler gear warning on M272 and M273)

2. Engine Number (R350) — Check if the balance shaft has been revised (pre-2010 cars are at risk)

3. Service History — including which engine (M272, M113 or M273) and evidence of major maintenance

4. Oil Leaks (R500 M113) — Any oil under the car or excessive oil consumption? (seals are failing)

5. Check Engine Light — Have codes been read? (P0016–P0019 indicate balance shaft issues; P2005 indicates intake manifold issues)

6. Intake Manifold Health (R500 M113) — Any loss of power or P2005 code? (flaps are failing)

7. Transmission — Any hard shifting? (7G-Tronic valve body failure is common)

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 — three engine families across the R-Class petrol's history.

M272 (3.5L V6)

Years2006–2010

Power268 hp / 258 lb-ft

2025 Enquiries[PATTERN DATA]

Avg. Recon Cost£2,500–£5,000 [MB-QUOTE]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

M272 (3.5L V6)2006–2010268 hp / 258 lb-ft[PATTERN DATA]£2,500–£5,000 [MB-QUOTE]

M113 (5.0L V8)2006–2010302 hp / 339 lb-ft[PATTERN DATA]£3,000–£5,500 [MB-QUOTE]

M273 (5.5L V8)2010–2013383 hp / 391 lb-ft[PATTERN DATA]£3,500–£7,500 [MB-QUOTE]

Technical Specs

M272 — 3.5 V6

Displacement4,966cc (5.0‑litre)

CylindersV8, 90° configuration

Compression Ratio10.0:1

Fuel SystemMulti-point fuel injection

ValvetrainSOHC, 3 valves per cylinder

ConstructionAll-aluminium block and heads

Transmission7-speed automatic (7G-Tronic)

Displacement3,498cc (3.5‑litre)

CylindersV6, 90° configuration

ValvetrainDOHC, 4 valves per cylinder

→ Compare R350 / R500 petrol engine prices for your Mercedes

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Market Intelligence

Most Common Failure

M272: Balance shaft failure / M113: Oil seals and intake manifold flaps / M273: Balance shaft/idler gear issues — the defining risks of each engine

Average Enquiry Mileage

M272: 60,000–100,000 miles / M113: 70,000–120,000 miles / M273: 60,000–90,000 miles【PATTERN DATA】

Average Replacement Cost

M272: £2,500–£5,000 / M113: £3,000–£5,500 / M273: £3,500–£7,500 reconditioned, supply only【MB-QUOTE】

Most Requested Engine Code

M113 — the reliable V8【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.

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every garage and engine rebuilder in our network is vetted, rated and reviewed by real R350 and R500 petrol owners, as part of the Engine Finders network, across all three engine generations — no matter which R-Class era you drive.
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see prices, warranty terms and supply & fit options side‑by‑side before you commit, with specialists who genuinely understand the M272's balance shaft, the M113's oil seals and intake manifold flaps, and the M273's idler gear concerns.
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