Is the Range Rover Sport D300 (AJ20D6) engine reliable?

Yes — the AJ20D6 is a significantly more reliable engine than the 306DT V6 it replaced. It's a modern, well-engineered inline-six with a chain-driven valvetrain and improved emissions systems. The main watchpoints are EGR cooler leaks (particularly on L494-era cars) and cooling system integrity — both are manageable with proper maintenance.

What are the common problems with the Range Rover Sport D300 engine?

EGR cooler coolant leak (more common on L494-era cars), cooling system issues (water pump, thermostat), and DPF regeneration issues from short journeys. The engine itself is fundamentally robust and not prone to the catastrophic failures seen on some earlier JLR diesels.

Is it worth replacing a Range Rover Sport D300 engine, or should I scrap the car?

Depends on vehicle value. A Range Rover Sport D300 is a £35,000–£80,000+ vehicle — a £6,500 recon is only 8–19% of the car's value, making replacement a clear decision. This is well within our 60% Land Rover scrap threshold.

How do I find my Range Rover Sport D300 engine code?

Listed on the VIN plate and vehicle documentation. The D300 engine code is AJ20D6 — a 3.0-litre inline-six diesel. Tell us your registration date and we'll confirm it for free.

Can I prevent the EGR cooler failure on a Sport D300?

On L494-era cars, early EGR cooler replacement is the most effective prevention — many specialists recommend replacing it as a preventative measure at 60,000–80,000 miles. On L461-era cars, the design was revised, making failure less likely. If you notice coolant loss, have the EGR cooler inspected immediately.

Land Rover Range Rover Sport D3002019–presentAJ20D6

Land Rover Range Rover Sport D300 Engine Replacement — Compare Prices & Get Quotes

The 3.0-litre inline-six Ingenium diesel (AJ20D6) powers the Range Rover Sport — a smooth, powerful, and efficient flagship diesel. Get quotes from trusted UK specialists today.

Supply & Fit Available

12-Month Warranty

Nationwide Delivery

12 Specialists

Supply & Fit Available

12-Month Warranty

Nationwide Delivery

12 Specialists

Range Rover Sport D300 Engines — from £2,500 to £9,500AJ20D6

Range Rover Sport D300 Engines — from £2,500 to £9,500· AJ20D6

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The RANGE ROVER SPORT D300 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?

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

Land Rover Range Rover Sport D300 Engine Replacement Costs

Supply Only£5,500–£8,200

Fitted (Indie)£6,900–£9,800

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£2,500–£4,500£3,800–£6,0001–6 monthsBudget priority; lower-mileage donor

Reconditioned Engine£5,500–£8,200£6,900–£9,80012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£7,000–£9,500£8,400–£11,10012–24 monthsLong-term ownership; 3+ year horizon

Main Dealer New£10,000–£14,000£11,500–£15,80024–36 monthsInsurance jobs, warranty claims

Figures above reflect the current AJ20D6 generation.

Labour estimate: Fitting a Range Rover Sport D300 engine typically takes 14–18 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer).

→ Compare Range Rover Sport D300 engine prices from UK specialists

Common Problems

1. EGR Cooler Leak

Symptoms: Coolant loss with no visible external leak, white exhaust smoke, occasional burning smell, engine warning light.

Typical mileage: 40,000–80,000 miles

Repair cost: £600–£1,200 (EGR cooler replacement) [PLACEHOLDER — confirm vs cost sheet]

Replacement cost: N/A — repair only (if caught before overheating)

🟠 Check - book inspection urgently if coolant levels drop

Our recommendation:

The EGR cooler is a known weak point on early AJ20D6 engines (L494 era). If you notice coolant loss with no visible leak, or white smoke from the exhaust, have the EGR cooler inspected immediately. Later L461 revisions improved the design, but it remains a watchpoint. Catching it early prevents overheating damage.

1. EGR Cooler Leak

Symptoms: Coolant loss with no visible external leak, white exhaust smoke, occasional burning smell, engine warning light.

Typical mileage: 40,000–80,000 miles

Repair cost: £600–£1,200 (EGR cooler replacement) [PLACEHOLDER — confirm vs cost sheet]

Replacement cost: N/A — repair only (if caught before overheating)

🟠 Check - book inspection urgently if coolant levels drop

Our recommendation:

2. Cooling System Integrity (Water Pump & Thermostat)

Symptoms: Slow warm-up, temperature fluctuations, coolant loss, heater not working properly, engine warning light.

Typical mileage: 50,000–90,000 miles

Repair cost: £400–£900 (water pump and thermostat replacement) [PLACEHOLDER — confirm vs cost sheet]

Replacement cost: N/A — repair only

🟡 Monitor - book inspection soon

Our recommendation:

The AJ20D6's cooling system is complex, with electric water pumps and multiple thermostats. If you notice temperature fluctuations or slow warm-up, have the system inspected. Replacing a failing water pump preventatively is far cheaper than the overheating damage it can cause.

3. DPF Regeneration Issues (Short Journey Use)

Symptoms: DPF warning light, reduced power, increased fuel consumption, automatic stop-start unavailable.

Typical mileage: 30,000–80,000 miles (depends on usage pattern)

Repair cost: £300–£800 (DPF clean or forced regeneration) [PLACEHOLDER — confirm vs cost sheet]

Replacement cost: N/A — repair only (unless the DPF is physically damaged)

🟡 Monitor - book inspection soon

Our recommendation:

Like all modern diesels, the AJ20D6 needs regular long runs to regenerate the DPF. If your D300 is used primarily for short journeys, plan a 30–45 minute motorway run every two weeks to allow passive regeneration. If the DPF warning light comes on, book a forced regeneration promptly.

Ready to Compare?

Get Matched With a Vetted Land Rover Specialist

12 vetted Land Rover specialists, every Range Rover Sport D300 covered, with a 12-month warranty as standard.

Get My Free Sport D300 Engine Quotes Now

Range Rover Sport D300 — 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.

Range Rover Sport D300 — 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 SenseEGR cooler leak✅ Yes£600–£1,200Straightforward — catch it before it causes overheatingWater pump/thermostat failure✅ Yes£400–£900Routine maintenance — do preventativelyDPF regeneration issues✅ Yes£300–£800Periodic service — forced regeneration or cleanTiming chain wear⚠️ Sometimes£1,500–£3,000Viable on lower-mileage examples; assess overall engine healthSevere overheating damage❌ Usually NoEngine replacementLittle left to salvage — replacement is the only option

Buying This Range Rover Sport D300? Check These First

Buy If

Documented EGR cooler service history (or replaced on L494-era cars)
Cooling system maintained with recent water pump and thermostat work
Regular long runs (DPF health) — or proof of forced regenerations
Full JLR service history with correct oil spec

Avoid If

Coolant loss with no diagnosis on L494-era D300 — EGR cooler may be failing
Temperature fluctuations with no cooling system history — walk away
DPF warning light with no regeneration history — could be a sign of heavy clogging
Engine warning light with no diagnosis — potentially expensive emissions system issues

Closing Verdict

The AJ20D6 is a fundamentally superior engine to the 306DT V6 it replaced — smoother, more powerful, and more efficient. It's not without its watchpoints — EGR cooler and cooling system integrity are the two main areas to monitor — but it's a more reliable base. Buy on full service history, and pay attention to L494-era EGR cooler records. A well-maintained D300 is a long-lived flagship diesel.

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

→ Compare Range Rover Sport D300 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 Range Rover Sport D300 engine prices before you buy

20+ Vetted Specialists UK Network

12-Month Warranty as Standard

Nationwide Delivery & Collection

Transparent Pricing, No Hidden Fees

Thousands of 320d Owners Helped

Buying Checklist

Before you buy a used Land Rover Range Rover Sport D300 (or before you commit to an engine replacement), check these:

Coolant Level — Check for unexplained loss; EGR cooler leak is a known issue on L494-era cars

Cold Start — Listen for smooth start; no chain rattle or injector noise on this engine

Service History — including which generation (L494 or L461) and confirmed maintenance

DPF Status — Check for warning lights; short journeys can cause clogging

Temperature Gauge — Check for fluctuations; water pump or thermostat may be failing

Oil Consumption — Does it use more than 1L per 1,000 miles?

Engine Warning Light — Have codes been read? Any unresolved emissions issues?

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.

AJ20D6 (3.0 inline-six diesel)

Years2019–2020

Power300 PS (296 bhp) @ 4,000 rpm; 650 Nm @ 1,500–2,500 rpm

2025 Enquiries— (pattern data)

Avg. Recon Cost£5,500–£7,800 [PLACEHOLDER]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

AJ20D6 (3.0 inline-six diesel)2019–2020300 PS (296 bhp) @ 4,000 rpm; 650 Nm @ 1,500–2,500 rpm— (pattern data)£5,500–£7,800 [PLACEHOLDER]

AJ20D6 (3.0 inline-six diesel, revised)2022–present300 PS (296 bhp) @ 4,000 rpm; 650 Nm @ 1,500–2,500 rpm— (pattern data)£5,800–£8,200 [PLACEHOLDER]

Technical Specs

AJ20D6 3.0 inline-six diesel

Displacement2,997 cc

Cylinders6-cylinder inline (straight-six)

Compression Ratio15.5:1

Fuel SystemCommon-rail direct injection

TurbochargerVariable-geometry turbocharger with electric wastegate actuator

→ Compare Range Rover Sport D300 engine prices for your Land Rover

Get quotes from trusted UK specialists in minutes.

Market Intelligence

Most Common Failure

EGR cooler coolant leak — particularly on L494-era cars

[PATTERN DATA]

Average Enquiry Mileage

45,000

–65,000 miles

[PATTERN DATA]

Average Replacement Cost

£6,500

reconditioned, supply only

[PLACEHOLDER — confirm vs cost sheet]

Most Requested Engine Code

AJ20D6

[PATTERN DATA]

Peak Enquiry Season

Autumn/Winter — cooling and DPF issues exposed

[PATTERN DATA]

Regional Demand

South East20%

London17%

South West14%

PATTERN DATA

Regional Demand Breakdown

20%South East

17%London

FAQ

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.

Find the best Land Rover Range Rover Sport D300 engine replacement UK drivers rely on. Compare prices from trusted specialists on EnginesMarket today and get back on the road with confidence — from £2,500 for a used unit to £9,500 for a fully rebuilt Ingenium diesel.

Compare Land Rover Range Rover Sport D300 Engine Prices Now

100% Free

No hidden fees

No Obligation

Get quotes with zero pressure

UK Specialists

20+ vetted experts

12-Month Warranty

As standard

Nationwide Delivery

Supply & fit available

100% Free

No hidden fees

No Obligation

Get quotes with zero pressure

UK Specialists

20+ vetted experts

12-Month Warranty

As standard

Nationwide Delivery

Supply & fit available