The Defender D300 sits in the modern L663-generation range, introduced in 2020 as a 3.0-litre six-cylinder diesel with mild-hybrid assistance. Using the Ingenium AJ300D, it replaced the earlier D240 as a more powerful and efficient option. The D300 is available across all three body styles — 90, 110 and 130 — and benefits from the 48V MHEV system that provides the DC-DC converter to manage the auxiliary electrical systems. It's one of the most popular diesel choices in the current Defender lineup, offering a balance of power and efficiency for both on-road and off-road use. Land Rover Defender D300 Engine Codes Ingenium AJ300D (D300) A 3.0-litre inline-six diesel with mild-hybrid assistance, fitted to the L663 Defender from 2020 to present. Known for the Ingenium timing chain pattern, DC-DC converter failure on the MHEV system, and early production (2019-2020) electrical injector faults — see the callout above. We replace timing chain components, injector seals, bearings, gaskets and the DC-DC converter as standard on every AJ300D rebuild. Check Your AJ300D D300 → [link to quote form] Land Rover Defender D300 Engine Compatibility The D300's AJ300D is fitted specifically to the L663-generation Defender, across all three body styles. Unlike earlier Defenders that used a range of different diesel engines (Td5, 300Tdi, 200Tdi), the L663 range uses a consistent engine architecture across its diesel options — the D200, D240, D250, D300 and D350 all share the same Ingenium AJ family design. However, the specific tuning, components and MHEV hardware vary between them, so we always confirm your exact D300 specification before quoting. Land Rover Defender D300 Applications by Generation Generation Chassis Body Style Years Engine Code Fuel L663 L663 90/110/130 2020–present Ingenium AJ300D Diesel MHEV Land Rover Defender D300 Engines by Year Year Generation Body Style Engine Code Fuel Service 2020 L663 90/110/130 Ingenium AJ300D Diesel MHEV Rebuild / Replacement 2021 L663 90/110/130 Ingenium AJ300D Diesel MHEV Rebuild / Replacement 2022 L663 90/110/130 Ingenium AJ300D Diesel MHEV Rebuild / Replacement 2023 L663 90/110/130 Ingenium AJ300D Diesel MHEV Rebuild / Replacement 2024 L663 90/110/130 Ingenium AJ300D Diesel MHEV Rebuild / Replacement 2025 L663 90/110/130 Ingenium AJ300D Diesel MHEV Rebuild / Replacement 2026 L663 90/110/130 Ingenium AJ300D Diesel MHEV Rebuild / Replacement We Cover Every Land Rover Defender D300 Model Year: ✓ Land Rover Defender D300 2020 Engine Rebuild ✓ Land Rover Defender D300 2021 Engine Rebuild ✓ Land Rover Defender D300 2022 Engine Rebuild ✓ Land Rover Defender D300 2023 Engine Rebuild ✓ Land Rover Defender D300 2024 Engine Rebuild If your registration year isn't listed above, get in touch — we'll confirm availability directly against your reg. Land Rover Defender D300 Engine Sizes ✓ Land Rover Defender D300 3.0 Litre Engine (Ingenium AJ300D, I6) Land Rover Defender D300 Fuel Types ✓ Land Rover Defender D300 Diesel MHEV Engine Rebuilds Land Rover Defender D300 Engine Costs A Land Rover Defender D300 engine rebuild starts from £2,800. A full replacement engine and fitting service is also available. Exact pricing depends on the condition of your existing engine and the parts required — submit your registration for a fixed-price quote within 30 minutes. Related Land Rover Defender Variants Looking for a different Defender engine? We also cover: [Defender D200 Engine →] · [Defender D240 Engine →] · [Defender D250 Engine →] · [Defender D350 Engine →] · [Defender P300 Engine →] · [Defender P400 Engine →] [← View All Land Rover Defender Engines] Frequently Asked Questions What engine does the Land Rover Defender D300 use? The Defender D300 uses the Ingenium AJ300D — a 3.0-litre inline-six diesel with mild-hybrid assistance. It's been fitted to L663-generation Defenders since 2020 across 90, 110 and 130 body styles. How much does a Land Rover Defender D300 engine rebuild cost? Rebuilds start from £2,800. Exact price depends on condition and parts required — submit your reg for a fixed-price quote. Which engine code is fitted to my Defender D300? Enter your registration on this page and we'll confirm your exact engine specification before you're quoted anything. Do you rebuild Ingenium AJ300D D300 engines? Yes. We replace timing chain components, injector seals, bearings, gaskets and the DC-DC converter as standard on every AJ300D rebuild. For early production models (2019-2020), we also inspect and replace affected electrical injectors. Do you supply used Defender D300 engines? Yes, in some cases a matched low-mileage used engine is the right option. Our team will advise honestly once we've matched your registration and understood your situation. Can you recover my Defender D300 if the engine has failed? Yes — nationwide recovery is available from £70, and most vehicles are collected within a few hours of booking. How long does a Defender D300 engine rebuild take? Most rebuilds are completed within 3-5 working days from the time your car arrives at our workshop. Is rebuilding better than fitting a used engine? For most D300 owners, yes. A rebuild removes the compatibility risk that comes with an unknown used unit's history, and comes with a 12-month unlimited-mileage warranty — often longer and more comprehensive than what a used engine supplier offers. <a name="quote-form"></a> Get Your Free Land Rover Defender D300 Fixed-Price Quote [Quote Form: Registration Number | Postcode | Name | Phone | Email | Issue/Enquiry Type (dropdown: Engine Failure / Replacement Needed / General Enquiry) | Submit] Most quotes returned within 30 minutes during working hours. json { "@context": "https://schema.org", "@graph": [ { "@type": "Organization", "@id": "https://landrovergarage.co.uk#organization", "name": "Land Rover Garage", "url": "https://landrovergarage.co.uk", "email": "info@landrovergarage.co.uk", "telephone": "+44 01268 944 234", "sameAs": [ "https://facebook.com/landroverrebuildgarageuk", "https://twitter.com/landroverrebuildgarageuk", "https://instagram.com/landroverrebuildgarageuk", "https://tiktok.com/@landroverrebuildgarageuk" ] }, { "@type": "AutoRepair", "@id": "https://landrovergarage.co.uk#autorepair", "name": "Land Rover Garage – Defender D300 Engine Rebuild Specialists", "url": "https://landrovergarage.co.uk/defender-d300-engines", "telephone": "+44 01268 944 234", "email": "info@landrovergarage.co.uk", "priceRange": "£££", "address": { "@type": "PostalAddress", "streetAddress": "Unit A5 Windsor Road, Commercial Estate, Ramsden Heath", "addressLocality": "Billericay", "postalCode": "CM11 1QE", "addressCountry": "GB" }, "openingHours": "Mo-Fr 09:00-18:00, Sa 11:00-14:00", "areaServed": "GB", "parentOrganization": { "@id": "https://landrovergarage.co.uk#organization" }, "brand": { "@type": "Brand", "name": "Land Rover" } }, { "@type": "Service", "serviceType": "Land Rover Defender D300 Engine Rebuild & Replacement", "provider": { "@type": "AutoRepair", "name": "Land Rover Garage" }, "areaServed": "GB", "offers": { "@type": "Offer", "priceCurrency": "GBP", "price": "2800", "description": "Land Rover Defender D300 engine rebuild starting price, Ingenium AJ300D" } }, { "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "What engine does the Land Rover Defender D300 use?", "acceptedAnswer": { "@type": "Answer", "text": "The Defender D300 uses the Ingenium AJ300D — a 3.0-litre inline-six diesel with mild-hybrid assistance. 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We continue to rebuild and replace Ingenium AJ300D engines for every Defender D300 on the road.