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Mayfair Rebuilds workshop with rebuilt JLR engine

/// Specialists in Jaguar Engine Replacement & Rebuilds

Quality Jaguar 306DT Engines for Sale, Low Mileage Rebuild Engines at Amazing Prices

Is your Jaguar experiencing engine failure, crankshaft damage, or low oil pressure? We supply, rebuild, and fit exact-code 306DT (AJV6D) engines. Our specialists handle everything from vehicle collection to final testing, delivering a reliable solution without the dealership price.

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Factory Standard
Engine Rebuilds

Built to OE specifications

In-House Strip
Machine & Build

All work carried out in-house

Up to 12 Month
Warranty

Peace of mind guaranteed

Nationwide Collection
& Delivery

Across the UK mainland

Expert Support
Before & After Fit

Real people, real expertise

Trusted By Jlr Owners Across the Uk

Land Rover
Range Rover
Jaguar

Jaguar 306DT Engine Details

Engine Make : Jaguar
Engine Fuel : Diesel
Engine Horse Power : 241HP
Engine Size : 3.0
Engine Code : 306DT
Engine Layout : V
Engine Actual CC : 2993
Engine Cylinders : 6
Engine Valves : 24
Engine Power KW : 177 kW
Engine Fuel Supply : Direct Injection
Engine Charge : Exhaust Turbo Charger
Engine Camshaft Drive : Rear Wheel Drive
/// COMMON Jaguar 306DT FAILURE POINTS

Common Jaguar 306DT Engine Faults Mayfair Rebuilds Diagnose & Resolve Expertly

We inspect these critical areas on every engine to identify the root cause of failure and prevent future issues.

No. Common Problem Common Symptoms Likely Cause Practical Solution
1 Crankshaft Bearing Failure Bottom-end metallic knocking, low oil pressure light, engine seizure. Original tangless bearing shells rotate in their housings, blocking oil flow. Inspect and install upgraded bearing shells designed to lock in place, along with polished crankshafts.
2 Engine Oil Dilution Rising oil levels on dipstick, smell of diesel in the oil, particulate filter errors. Interrupted DPF regenerations during short journeys force diesel past piston rings into the sump. Flush engine, replace diluted oil, and clean DPF system to reset normal regeneration cycles.
3 Turbocharger Issues Loss of power, engine lag, blue exhaust smoke, whistling noise. Failing actuators or oil starvation damaging the turbo bearings. Rebuild or replace turbos, inspect oil feed lines, and test actuator response.
4 Cracked Valve Covers Whistling noise, oil leaks, drop in performance, underboost codes. Thermal stress over time cracks the composite plastic valve covers. Replace cracked plastic covers with reinforced units and install new gaskets.
5 EGR Cooler Leakage Loss of coolant, white exhaust steam, rough idle on cold starts. Internal cracks in the EGR cooler heat exchanger leak coolant into exhaust gas. Pressure-test the cooling circuit and replace cracked EGR cooler assemblies.
6 Oil Pump Wear Flickering oil light, top-end engine rattle, accelerated bearing wear. Internal pressure relief valve wear or sludge buildup impeding oil flow. Install a new, high-efficiency oil pump and thoroughly clean the sump and pickup pipe.
7 Coolant Outlet Flange Leaks Coolant loss, engine overheating, sweet coolant smell. The plastic coolant bypass pipes beneath the intake manifold become brittle and crack. Replace brittle plastic coolant pipes with updated, durable components.
8 Timing Belt Wear Starting failure, engine misfire, severe timing loss. Belts exceeding their age/mileage limits, leading to teeth stripping or snapping. Fit complete premium timing belt kit, including new tensioners, pulleys, and fuel pump belt.
/// ENGINE REPLACEMENT PROCESS

Our 4 Step Engine Replacement Process

A clear, technician-led route from diagnostic recovery to final testing and handover for Jaguar engines.

01
Vehicle and fault assessment

Vehicle & Fault Assessment

We assess symptoms, engine condition and likely failure path before recommending the next step.

02
Engine code and compatibility check

Engine Code &
Compatibility Check

Exact engine code, platform compatibility and replacement criteria are verified for the correct fit.

03
Engine rebuild preparation

Rebuild / Preparation /
Sourcing Path

We determine the right route — used, reconditioned or rebuilt — then prepare or source accordingly.

04
Supply fitment and handover

Supply, Fitment &
Handover

The engine is supplied, fitted, tested and handed over with aftercare guidance and support.

Technician AssessedChecked by experienced engine specialists.

Code MatchedExact engine code and platform verified for perfect fit.

Prepared to StandardEngines prepared, tested and quality assured.

Fitted & SupportedInstalled, tested and backed by aftercare support.

WHY CHOOSE MAYFAIR

Why JLR Owners Choose Our Workshop for Decades

In-house standards, engine code compatibility verification, and dependable aftercare managed by one dedicated team.

01

Direct Jaguar Expertise

Specialist knowledge across Jaguar engine replacement, rebuild and diagnostics.

02

One Accountable Team

One team manages assessment, sourcing or rebuild route, fitment planning and handover.

03

In-House Standards

Engines are prepared, rebuilt and quality-checked under workshop-controlled standards.

04

Code & Compatibility Control

Engine code, platform and fitment criteria are verified before any engine is recommended.

Mayfair Rebuilds Workshop-Led
Advantage
05

Rebuild Depth

Strip-down inspection, component replacement and machining are carried out where required.

06

Aftercare & Warranty

Clear warranty-backed support and post-fit guidance for added peace of mind.

07

UK Sourcing Network

Credible UK supply channels help secure suitable donor and replacement engines.

08

Supply & Fit Coordination

From engine selection to installation planning, the whole route is coordinated clearly.

Reviews & Proof

Trusted by Land Rover, Range Rover & Jaguar Owners Across the UK

Verified feedback from customers who chose Mayfair Rebuilds for Land Rover engine
replacement, Range Rover engine rebuilds, Jaguar engine supply and fit, and workshop-
prepared used, rebuilt and reconditioned engines. Real vehicle references, real outcomes
and support you can trust.

★ ★ ★ ★ ★
5.0 / 5 Average Customer Rating Based on verified customer reviews
JLR JLR Specialists
Workshop Prepared
UK-Wide Support
★★★★★“

Daniel M.

Range Rover Sport 3.0 SDV6

Engine issue diagnosed properly, options explained clearly, and the replacement unit fitted without drama. Smooth service from start to finish.

★★★★★“

Sarah T.

Land Rover Discovery 4 3.0 TDV6

Other companies just wanted to sell an engine. Mayfair actually checked compatibility, explained the rebuild route, and delivered exactly what was promised.

★★★★★“

James R.

Jaguar XF 2.0 Ingenium Diesel

The reconditioned engine has been faultless. Excellent communication, realistic timescales and proper aftercare once the car was back on the road.

★★★★★“

Natalie P.

Range Rover Velar 2.0 Ingenium

Professional workshop, clear paperwork and no hard sell. They matched the correct engine code and coordinated everything properly.

★★★★★“

Michael C.

Jaguar F-PACE 3.0 Supercharged

Rare to find this level of technical knowledge and customer service together. The engine rebuild quality and handover were excellent.

25+ Years Experience

Specialist engine
replacement knowledge.

Warranty-Backed Support

Up to 12 months cover
for added confidence.

UK-Wide Coverage

Supply, fitment support
and nationwide reach.

Thousands Helped

Used, rebuilt and
reconditioned engines
supplied and rebuilt.

Our Workshop Gallery

JLR engine work gallery 1
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Reconditioned & Used Jaguar 306DT Engines: Saving Up to 40% on Full Replacement

When your Jaguar’s 3.0-litre V6 diesel engine develops a major fault, we understand the stress, confusion, and high costs that follow. Whether your vehicle has suffered a snapped crankshaft, spun main bearings, severe turbo failure, or oil dilution from a blocked particulate filter, finding a reliable repair route is critical. At Mayfair Rebuilds, we offer a complete engine reconditioning and replacement service designed to get your Jaguar back on the road with total peace of mind. Operating from our fully equipped engineering facility, we manage the entire process under one roof—from vehicle recovery and deep diagnostics to engine machining, assembly, fitting, and final testing.

By choosing our workshop-prepared reconditioned or low-mileage used engine packages, you can save up to 40% compared to main dealership replacement bills without compromising on components, clearances, or workmanship. We do not believe in quick patches or cosmetic repairs. On every 306DT rebuild, we strip the engine block down to its bare core, chemically clean all components, and reconstruct the bottom end using upgraded, locking main bearing shells to eliminate the structural weaknesses found in original OEM designs.

Furthermore, our technicians install a brand-new timing belt kit, fresh water pump, and oil pump, while thoroughly pressure-testing the twin-turbochargers, flushing the EGR coolers, and chemically cleaning the DPF to resolve any surrounding systems that could trigger a repeat failure. We sync the fuel injectors, clear historic fault codes from your vehicle’s ECU, and conduct an extensive hot-cycle road test to verify factory-standard compression and oil pressure.

Every single engine we supply and fit is backed by our comprehensive up to 12-month warranty. We can coordinate secure, fully insured flatbed recovery of your vehicle from any home, workplace, or garage in the UK directly to our workshop bays. Contact our technical team today with your vehicle registration to receive a transparent, clear, and itemised estimate.

 

Frequently Asked Questions

Common Questions Answered

Everything you need to know about our engine replacement, rebuild and supply process.

The 306DT engine is a 3.0-litre V6 diesel engine used in selected Jaguar and Land Rover models. It is known for strong torque and smooth performance, but like many high-mileage JLR diesel engines, it can develop issues with crankshaft bearings, turbochargers, oil dilution, valve covers, and cooling system leaks.
This engine is widely used in prestige models, including the Jaguar XF, Jaguar XJ, Jaguar F-PACE, Land Rover Discovery 4, Range Rover Sport, and Range Rover Velar.
Common issues include spun crankshaft bearings, often leading to a broken crankshaft, oil dilution from interrupted DPF regeneration, plastic valve cover cracking, coolant leaks, and carbon build-up in the EGR cooler.
Yes, we offer a complete supply-and-fit service. We handle the collection, engine building, installation, injector coding, and extensive testing before vehicle handover.
If your engine has suffered severe crankshaft bearing damage or bottom-end seizure, a replacement or full rebuild is usually required. Localised repairs are possible for minor leaks, valve covers, or single turbo actuator issues.
A rebuilt engine is completely stripped, cleaned, and reassembled with upgraded bearings, seals, and gaskets, returning it to near-zero-hour condition. A used engine is a budget-friendly option that we inspect thoroughly before installation.
Typically, the entire turnkey replacement process takes between 7 to 10 working days, including collection, installation, calibration, and road testing.
We always inspect and clean the DPF, check the turbochargers for internal play, replace vulnerable plastic coolant bypass flanges, and fit a new timing belt kit and water pump.
You can fill out the registration lookup at the top of this page, call our team directly, or email us with your vehicle registration and symptoms to receive an itemized estimate.