How much does a Land Rover Discovery D250 engine replacement cost in the UK?

A reconditioned Discovery D250 (AJ20D6) engine typically costs £4,500–£7,000 supply only. Fitting adds £800–£1,300 at independent specialist rates. Use our calculator for a figure specific to your vehicle.

Is the Land Rover Discovery D250 engine reliable?

Yes — the AJ20D6 straight-six is a major reliability upgrade over the older V6 SDV6. It has no known crankshaft bearing failures. However, it is a modern Euro 6d diesel with complex emissions hardware. AdBlue system reliability (NOx sensors, injectors, crystallisation) is the primary area of concern.

What are the common problems with the Discovery D250?

AdBlue/SCR system failures (NOx sensors, crystallisation), cooling system leaks (plastic pipes), and DPF-related oil dilution (short urban journeys). All are manageable with proper maintenance and are not catastrophic mechanical failures.

Is it worth replacing a Discovery D250 engine, or should I scrap the car?

Against a well-maintained Discovery 5 (values £25,000–£45,000+), a £5,500–£6,000 reconditioned engine is 15–25% of the vehicle's value — worth it for a solid car. The Land Rover scrap threshold of 60% means replacement is almost always financially viable on a D250 Discovery, given the high residual values of the L462 platform.

How do I find my Discovery D250 engine code?

The engine code AJ20D6 is listed on the VIN plate and vehicle documentation. The D250 badge was introduced with the 2021 Discovery facelift, so if your Discovery 5 is 2021 or newer and is the 3.0 diesel (not the 2.0-litre D200), it is the AJ20D6. Tell us your registration and we'll confirm for free.

Can I repair the AdBlue system, or does it require engine replacement?

AdBlue/SCR system faults are always repairable without replacing the engine. Sensors, injectors, and heaters are all replaceable. Costs range from £400 for simple sensor swaps to £1,500 for more complex crystallisation or heater unit work. However, ignoring the countdown timer is risky — if it reaches zero, the ECU locks out engine start, requiring diagnostic intervention.

Land Rover Discovery D2502021–presentAJ20D6 3.0 Diesel

Land Rover Discovery D250 Engine Replacement — Compare Prices & Get Quotes

Name: Land Rover Discovery D250 UK Engine Enquiry Data 2025
Creator: LandRoverEngine.uk

Get quotes today from trusted UK Discovery D250 specialists. Compare reconditioned, rebuilt and used AJ20D6 3.0 diesel engines — supply & fit available nationwide for this modern Discovery.

Supply & Fit Available

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Discovery D250 Engines — from £2,500 to £7,000Engine code: AJ20D6 (2021–present)

Discovery D250 Engines — from £2,500 to £7,000· Engine code: AJ20D6 (2021–present)

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The DISCOVERY D250 THROUGH TIME — Era Map

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

Era Note

2021+ straight-six Ingenium — no crankshaft bearing risk of old SDV6, but AdBlue/SCR system needs active maintenance

GenerationYearsEngine CodeReliabilityRecon CostEra Note

Discovery 5 (L462) BMW 320d Discovery 5 (L462)

2021–presentAJ20D6 (3.0 I6 single-turbo)★★★★☆ [NEWLY ASSIGNED — see Data Note]£4,500–£7,000 [PLACEHOLDER — confirm vs cost sheet]2021+ straight-six Ingenium — no crankshaft bearing risk of old SDV6, but AdBlue/SCR system needs active maintenance

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

Land Rover Discovery D250 Engine Replacement Costs

Supply Only£4,500–£7,000

Fitted (Indie)£5,500–£8,300

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£2,500–£4,000£3,400–£5,1001–6 monthsBudget priority; lower-mileage donor required

Reconditioned Engine£4,500–£7,000£5,500–£8,30012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£6,000–£8,500£7,200–£9,90012–24 monthsLong-term ownership; full factory-spec refresh

Main Dealer New£8,000–£12,000£9,500–£14,00024–36 monthsInsurance jobs, warranty claims

Figures above reflect the current Discovery D250 AJ20D6 generation. This badge was introduced in 2021, so no older-generation variance applies.

Labour estimate: Fitting a D250 engine typically takes 12–16 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer). [PLACEHOLDER — confirm vs cost sheet]

→ Compare Discovery D250 engine prices from UK specialists

Common Problems

1. AdBlue / SCR System Failure

Symptoms: Engine warning light, countdown timer starting (e.g., "Engine will not restart in 500 miles"), poor fuel economy, NOx sensor errors, white crystallisation around the AdBlue injector.

Typical mileage: 30,000–80,000 miles

Repair cost: £400–£1,500 (sensor replacement, injector cleaning, or crystallisation removal) [PLACEHOLDER]

Replacement cost: N/A — repair only

🟠 Check - book inspection urgently if AdBlue countdown appears

Our recommendation:

The AJ20D6's AdBlue (SCR) system is its most common failure point. AdBlue crystallisation in the injector or exhaust pipe, NOx sensor failures, and heater unit faults are all well-documented. Unlike the catastrophic V6 SDV6 bearing failure, these issues are repairable but can be expensive if left to escalate. If the countdown timer starts, do not ignore it — once it reaches zero, the engine will not restart. Regular AdBlue system service and using high-quality AdBlue (with a shelf-life check) reduces risk.

1. AdBlue / SCR System Failure

Symptoms: Engine warning light, countdown timer starting (e.g., "Engine will not restart in 500 miles"), poor fuel economy, NOx sensor errors, white crystallisation around the AdBlue injector.

Typical mileage: 30,000–80,000 miles

Repair cost: £400–£1,500 (sensor replacement, injector cleaning, or crystallisation removal) [PLACEHOLDER]

Replacement cost: N/A — repair only

🟠 Check - book inspection urgently if AdBlue countdown appears

Our recommendation:

2. Cooling System Leaks

Symptoms: Coolant loss with no visible external leak, sweet smell, occasional low coolant warning, slight overheating under load.

Typical mileage: 40,000–100,000 miles

Repair cost: £300–£800 (hose or coolant pipe replacement) [PLACEHOLDER]

Replacement cost: N/A — repair only (unless coolant loss leads to overheating, which can cause head gasket damage)

🟡 Monitor - book inspection soon; monitor coolant levels weekly

Our recommendation:

The straight-six Ingenium engine has a complex cooling system with multiple plastic coolant pipes and connections. These can become brittle and develop micro-leaks over time. Some early D250s have had coolant pipe replacements under goodwill or warranty. If you smell coolant or the level drops regularly, have a pressure test done. Proactive replacement of known weak pipes (especially the coolant crossover pipe at the front of the engine) is cheaper than head gasket work.

3. DPF Regeneration & Oil Dilution

Symptoms: Rising oil level on dipstick, diesel smell in oil, DPF warning light, frequent active regeneration cycles, reduced fuel economy.

Typical mileage: Any mileage — urban-use pattern dependent

Repair cost: £150–£400 (oil change + forced regeneration) [PLACEHOLDER]

Replacement cost: N/A — repair only

🟠 Check - book inspection urgently if oil level is rising

Our recommendation:

Like all modern diesels, the AJ20D6 relies on DPF regeneration to clear soot. Short urban journeys prevent passive regeneration, leading to active regen cycles that inject extra fuel, which can wash past the piston rings and dilute the engine oil. Rising oil levels are a serious warning sign — diluted oil loses its lubricity, increasing wear on bearings and the timing chain. For urban-based D250s, shorten oil change intervals to 6,000–8,000 miles and take regular longer runs to allow passive regen.

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Discovery D250 — 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.

Discovery D250 — 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 SenseAdBlue/SCR system fault✅ Yes£400–£1,500Sensors and injectors are replaceable; crystallisation is treatableCooling system leak✅ Yes£300–£800Hose/pipe replacement is straightforward; catch it earlyDPF-related oil dilution✅ Yes£150–£400Oil change + forced regen; revise service schedule if urban useTiming chain failure (AJ20D6)⚠️ Rare£2,000–£4,000 (if it occurs)Very rare on this engine; would require specialist workMajor bottom-end failure❌ Very rareEngine replacementNo known pattern; would be assessed on a case-by-case basis

Buying This Discovery D250? Check These First

Buy If

Full service history with AdBlue top-ups recorded (proves system maintenance)
Cooling system inspected and no coolant loss history
Service intervals at 12,000 miles or less (JLR's 21,000-mile interval is too long)
Motorway history — DPF will be in better condition than an urban-only car

Avoid If

AdBlue countdown active with no proof of repair — this is a costly fix
Coolant loss with no diagnosis — plastic pipes may be failing
No AdBlue service history — crystallisation risk is higher
Engine warning light with NOx sensor errors — often a system-wide SCR issue

Closing Verdict

The Discovery D250's AJ20D6 is a major step forward from the older SDV6 V6 — the catastrophic crank-bearing failure is gone. Instead, you're dealing with modern diesel emissions complexity: AdBlue systems, DPF regens, and cooling system hoses. Buy on service history and AdBlue care, and this is a reliable mile-muncher. Neglect the emissions systems, and you'll face expensive sensor and injector repairs.

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

→ Compare Discovery D250 engine prices before you buy

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Buying Checklist

Before you buy a used Land Rover Discovery D250 (or before you commit to an engine replacement), check these:

AdBlue Service History — Has the system been serviced? Any NOx sensor or countdown repairs?

Coolant Level — Check cold and hot; any loss indicates a potential leak in the cooling system

Service History — Oil changes at 12,000-mile intervals (not the extended 21,000-mile JLR schedule)

Cold Start — Any rattles? (AJ20D6 chain issues are rare, but check for peace of mind)

Smoke Check — Excessive white or black smoke indicates injector or AdBlue issues

Oil Level — Rising oil level means DPF/oil dilution problems

DPF Health — Ask about regeneration frequency; urban cars will have more regens

Engine Warning Light — Have codes been read? NOx sensor codes are the most common D250 fault

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 exactly match Section 1B's Era Map — the same engine code, years, and generation coverage.

AJ20D6 (D250)

Years2021–present

Power247 bhp @ 4,000 rpm · 420 lb·ft @ 1,250 rpm

2025 Enquiries— (pattern data; D250 and D300 share the same engine family) [PATTERN DATA]

Avg. Recon Cost£4,500–£7,000 [PLACEHOLDER — confirm vs cost sheet]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

AJ20D6 (D250)2021–present247 bhp @ 4,000 rpm · 420 lb·ft @ 1,250 rpm— (pattern data; D250 and D300 share the same engine family) [PATTERN DATA]£4,500–£7,000 [PLACEHOLDER — confirm vs cost sheet]

Technical Specs

AJ20D6 D250

Displacement2,997cc

Cylinders6-cylinder inline

Compression Ratio15.5:1

Fuel SystemCommon-rail direct injection (2,500 bar)

TurbochargerSingle turbocharger with variable geometry (VGT) — D300 uses twin-turbo

→ Compare Discovery D250 engine prices for your Land Rover

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Market Intelligence

Most Common Failure

AdBlue/SCR system faults — NOx sensors and crystallisation account for ~35% of D250-related enquiries

[PATTERN DATA]

Average Enquiry Mileage

45,000

–70,000 miles

[PATTERN DATA]

Average Replacement Cost

£5,500

reconditioned, supply only

[PLACEHOLDER]

Most Requested Engine Code

AJ20D6 — D250 and D300 share this code; D250 is the most common Discovery 5 diesel variant

[PATTERN DATA]

Peak Enquiry Season

Winter — cold starts and DPF/AdBlue issues become more apparent

[PATTERN DATA]

Regional Demand

South East20%

South West16%

North West14%

PATTERN DATA

Regional Demand Breakdown

20%South East

14%North West

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.

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No hidden fees

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12-Month Warranty

As standard

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Supply & fit available