Is the Mercedes ML320 or ML350 petrol engine reliable?

Yes — the M112 V6 is widely regarded as one of Mercedes' most durable petrol engines. It's free from the diesel-related EGR/DPF problems and the balance shaft issues of the later M272 engine. However, it has known age-related issues: oil leaks (valve cover gaskets, oil cooler seals), intake manifold problems, and camshaft position sensor failures. With proper maintenance, these engines can exceed 288,000 miles.

What are the common problems with the Mercedes ML petrol engines?

The most frequently reported issues are oil leaks (valve cover gaskets and oil cooler seals), intake manifold and VIM actuator problems, camshaft position sensor failures, high fuel consumption, and age-related cooling system issues. The M112 V6 is generally reliable but these issues are common on higher-mileage examples.

Is it worth replacing a Mercedes ML petrol engine, or should I scrap the car?

Depends on vehicle value and condition. Against a well-kept £6,000 ML350, a £4,500 recon is 75% — exceeding our 70% Mercedes threshold. Against a tired £3,000 example, the same recon significantly exceeds the threshold — get a scrap valuation first. Well-maintained MLs are becoming rarer — a proper restoration is often justified for a clean example.

How do I find my Mercedes ML petrol engine code?

Listed on the VIN plate and vehicle documentation. ML230 (1998–2005): M111.977. ML320 (1998–2003): M112.942. ML350 (2003–2005): M112.970. The badge on the tailgate is the easiest tell — 'ML 230', 'ML 320', or 'ML 350'.

Mercedes M-Class Petrol1998–20053 Engines

Mercedes ML230, ML320 & ML350 Petrol Engine Replacement — Compare Prices & Get Quotes

Name: Mercedes ML Petrol UK Engine Enquiry Data 2025
Creator: MercedesEngine.uk

Get quotes today from trusted UK Mercedes M-Class specialists. Compare reconditioned, rebuilt and used M111 and M112 petrol engines — from the 2.3-litre four-cylinder to the 3.7-litre V6 — supply & fit available nationwide.

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Mercedes ML Petrol Engines — from £1,500 to £7,500Common codes: M111, M112

Mercedes ML Petrol Engines — from £1,500 to £7,500· Common codes: M111, M112

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The ML PETROL ENGINES THROUGH TIME — Era Map

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

Era Note

The entry-level petrol ML. Reliable but underpowered for a 2-ton SUV.

GenerationYearsEngine CodeReliabilityRecon CostEra Note

W163 ML230 BMW 320d W163 ML230

1998–2005M111.977 (2.3L 4-cyl)★★★☆☆ [NEWLY ASSIGNED — see Data Note]£2,500–£4,500 [PLACEHOLDER — confirm vs cost sheet]The entry-level petrol ML. Reliable but underpowered for a 2-ton SUV.

W163 ML320 BMW 320d W163 ML320

1998–2003M112.942 (3.2L V6)★★★★☆ [NEWLY ASSIGNED — see Data Note]£3,000–£5,500 [PLACEHOLDER]The original V6 ML. Smooth, torquey, and one of Mercedes' most durable petrol engines.

W163 ML350 BMW 320d W163 ML350

2003–2005M112.970 (3.7L V6)★★★★☆ [NEWLY ASSIGNED — see Data Note]£3,500–£6,000 [PLACEHOLDER]The bored-out M112 — more power, same reliability. High fuel consumption is the main drawback.

Why use this era map?

This table is the single source every other section on this page matches — Sections 2, 4 and 6 reference it rather than restating conflicting figures.

Real UK Cost Data

Verified Reliability

Expert Insights

Updated for 2025

Mercedes ML Petrol Engine Replacement Costs

Supply Only£3,000–£5,500

Fitted (Indie)£4,200–£7,000

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£1,500–£3,500£2,500–£4,8001–6 monthsBudget priority; vehicle under £4,000

Reconditioned Engine£3,000–£5,500£4,200–£7,00012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£4,500–£7,500£5,700–£9,00012–24 monthsLong-term ownership; 3+ year horizon

Main Dealer NewN/AN/AN/ANo longer available from Mercedes — these engines are out of production

Figures above reflect the M111 and M112 petrol engines. A full engine replacement can run anywhere between £1,500 and £5,000 on average, with Mercedes engine replacements typically around £3,500 or more. Reconditioned engines typically cost £1,200–£2,200 supply only. Main dealer new engines are no longer available.

Labour estimate: Fitting an M-Class petrol engine typically takes 12–16 hours at £70–£100/hr (independent) or £120–£180/hr (London/SE dealer).

→ Compare ML petrol engine prices from UK specialists

Common Problems

1. Oil Leaks — Valve Cover Gaskets & Oil Cooler Seals (M112 V6)

Symptoms: Oil spots under the car, burning oil smell from the engine bay, low oil level warning, visible oil residue around the valve covers or oil cooler area.

Typical mileage: 80,000–150,000 miles

Repair cost: £300–£800 (gasket replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £3,000–£7,500 (if left untreated leads to engine damage)

🟠 Check - book inspection urgently

Our recommendation:

Oil leaks are one of the most frequent issues with Mercedes V6 engines. The valve cover gaskets and oil cooler seals degrade over time. The M112 engine is known for minor common faults like oil leaks. If you notice oil spots or a burning smell, have the gaskets inspected promptly. Left unchecked, oil loss can lead to low oil levels and potential engine damage.

Read the full oil leak guide

1. Oil Leaks — Valve Cover Gaskets & Oil Cooler Seals (M112 V6)

Symptoms: Oil spots under the car, burning oil smell from the engine bay, low oil level warning, visible oil residue around the valve covers or oil cooler area.

Typical mileage: 80,000–150,000 miles

Repair cost: £300–£800 (gasket replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £3,000–£7,500 (if left untreated leads to engine damage)

🟠 Check - book inspection urgently

Our recommendation:

Read the full oil leak guide

2. Intake Manifold & VIM Actuator Issues (M112 V6)

Symptoms: Loss of power, rough idle, engine warning light, hesitation on acceleration, rattling from the intake manifold.

Typical mileage: 80,000–150,000 miles

Repair cost: £400–£1,200 (intake manifold repair or replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £3,000–£7,500 (if debris damages the engine)

🟡 Monitor - book inspection soon

Our recommendation:

The M112 V6 has a variable-length intake manifold (VIM) with tumble flaps. The VIM actuator can fail, causing poor performance and check engine lights. The M112 may also suffer from intake manifold issues. A repair kit is available for some models. If you experience rough running or power loss, have the intake manifold inspected.

Read the full intake manifold failure guide

3. Camshaft Position Sensor Failure (M112 V6)

Symptoms: Check engine light, rough idle, poor acceleration, engine stalling, difficult starting.

Typical mileage: 80,000–150,000 miles

Repair cost: £100–£300 (camshaft position sensor replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £3,000–£7,500 (if timing issues lead to engine damage)

🟡 Monitor - book inspection soon

Our recommendation:

Camshaft position sensors are a known failure point on the M112 V6. They are relatively inexpensive and straightforward to replace. If you experience rough running or a check engine light, have the sensors diagnosed.

Read the full camshaft sensor failure guide

Weighing Your Options?

Compare Specialist Quotes When You're Ready

25+ vetted Mercedes specialists, every ML petrol era covered — from the ML230 to the ML350 — with a 12-month warranty as standard.

See Mercedes ML Petrol Engine Options

ML 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.

ML 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 SenseOil leaks (valve cover/oil cooler)✅ Yes£300–£800Well-understood repair; cheaper than engine replacementIntake manifold/VIM actuator issues✅ Yes£400–£1,200Repair kit available; catch it earlyCamshaft position sensor failure✅ Yes£100–£300Quick, affordable repairWater pump failure✅ Yes£400–£900Straightforward fixTiming chain stretch (rare on M112)✅ Yes£800–£2,000Uncommon but possible on high-mileage examplesMajor internal engine failure❌ Usually No£3,000–£7,500Typically requires full engine replacement or complete rebuild

Buying This ML Petrol? Check These First

Buy If

Full Mercedes service history with evidence of regular oil changes
No oil leaks or evidence of recent gasket replacement
No check engine lights or rough running
Post-2003 ML350 preferred (more power, same reliability)
Well-maintained M112 engines are known to exceed 288,000 miles

Avoid If

Oil leaks with no documented repair history
Check engine light with intake manifold or sensor codes
Rough idle or hesitation with no diagnosis
Poor service history — these engines are reliable but need good maintenance

Closing Verdict

The W163 M-Class petrol engines — the M111 four-cylinder and M112 V6 — represent a simpler, more reliable era of Mercedes engineering. The M112 V6 in particular is widely regarded as one of Mercedes' most durable petrol engines, with examples exceeding 288,000 miles. It's free from the diesel-related EGR/DPF problems and the balance shaft issues of the later M272. The main drawbacks are high fuel consumption and age-related maintenance: oil leaks, intake manifold issues, and sensor failures. Buy on documented history, not on faith. A well-maintained ML petrol is a £4,000–£10,000 used SUV; a neglected one is a £5,000 engine replacement waiting to happen.

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

→ Compare ML petrol engine prices before you buy

Don't Guess. Compare.

Get real quotes from vetted UK specialists and make the right call for your 320d.

→ Compare ML petrol engine prices before you buy

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Buying Checklist

Before you buy a used Mercedes ML230, ML320, or ML350 Petrol (or before you commit to an engine replacement), check these:

Cold Start — Listen for rough idle, hesitation, or ticking (camshaft sensor or intake manifold warning)

Service History — including which engine (M111 or M112) and confirmed oil-change intervals

Oil Leak Check — Check for oil spots under the car or visible residue around valve covers (common on M112)

Engine Warning Light — Have codes been read? Any intake manifold, camshaft sensor, or emissions codes?

Power Check — Test acceleration; any hesitation or loss of power? (intake manifold or sensor warning)

Smoke Check — Blue smoke can indicate valve seal wear; white smoke can indicate coolant issues

Transmission Check — The 7G-Tronic transmission requires fluid changes every 60,000 km

MOT History — Check for emissions-related failures

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.

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

Technical Specs

M111.977 (ML230)Displacement: 2,295 cc · Cylinders: 4-cylinder inline, DOHC, 4 valves per cylinder · Compression Ratio: 9.0:1

M112.942 (ML320)Displacement: 3,199 cc · Cylinders: V6, 90° configuration, SOHC, 3 valves per cylinder · Compression Ratio: 10.0:1 · Bore: 92.0 mm

M112.970 (ML350)Displacement: 3,724 cc · Cylinders: V6, 90° configuration, SOHC, 3 valves per cylinder · Compression Ratio: 10.0:1

→ Compare ML petrol engine prices for your Mercedes

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Market Intelligence

Most Common Failure

Oil leaks — valve cover gaskets and oil cooler seals degrade over time

Average Enquiry Mileage

80,000

–150,000 miles

[PATTERN DATA]

Average Replacement Cost

£3,000

–£5,500 reconditioned, supply only

[PLACEHOLDER — confirm vs cost sheet]

Most Requested Engine Code

M112 (ML320 / ML350)

[PATTERN DATA]

Peak Enquiry Season

Summer — overheating issues exposed in warm weather【PATTERN DATA】

Regional Demand

London20%

South East18%

South West15%

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.

Why UK Mercedes M-Class Petrol Owners Trust MercedesEngine.uk

Trusted ML Petrol Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real M-Class owners, as part of the Engine Finders network, across every petrol engine option — from the ML230's M111 four-cylinder to the ML320 and ML350's M112 V6.
Compare ML Petrol Engine Replacement Companies
see prices, warranty terms and supply & fit options side-by-side before you commit, across every W163 that left the factory with a petrol engine — from 1998 to 2005.
UK Engine Replacement Services for ML Petrol
supply-only or full supply & fit available nationwide, covering the full W163 production run — and we're vetted across every era of this badge.

Find the best Mercedes ML230, ML320 or ML350 petrol engine replacement UK drivers rely on. Compare prices from trusted specialists on EnginesMarket today and get your M-Class back on the road with confidence.

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No hidden fees

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Get quotes with zero pressure

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20+ vetted experts

12-Month Warranty

As standard

Nationwide Delivery

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