Velar D300 V6 vs Inline-Six — Which Should You Buy?

The inline‑six (AJ20D6) wins for most Velar buyers — it delivers superior refinement, a stronger torque curve, and a significantly lower risk of catastrophic failure than the V6 (306DT), albeit with a higher purchase price. The V6 remains a viable budget choice if you're prepared for its crankshaft bearing risk.

V6 (306DT): 980 enquiries in 2025, typical value £22,000–£55,000, recon supply £6,500–£9,500 [EM-VERIFIED / EM-QUOTE]
Inline‑six (AJ20D6): 590 enquiries (combined with AJ200D/Jaguar applications), recon supply est. £5,500–£8,500 [EM-VERIFIED / ESTIMATED]
V6 carries a catastrophic crankshaft bearing failure risk, typically 80k–140k miles [PATTERN DATA]
Inline‑six has a more robust bottom end, better cooling, and no widespread bearing issues
Over a five‑year ownership window, the inline‑six typically costs less to maintain despite higher initial purchase price

Full spec comparison, ownership cost analysis, and which engine fits your budget and driving needs below.

At a Glance

	V6 (306DT)	Inline‑Six (AJ20D6)
Years in Velar	2017–2021 (pre‑facelift)	2021–present (facelift)
Layout	3.0L V6 diesel	3.0L inline‑6 diesel
2025 UK Enquiries (all models)	980 [EM-VERIFIED]	590 (shared with Jaguar) [EM-VERIFIED]
Recon Supply Cost	£6,500–£9,500	£5,500–£8,500 [ESTIMATED]
R&R Labour Hours	15–20 hrs	14–18 hrs (straight‑six easier access)
Defining Failure	Crankshaft bearing (catastrophic)	Early cooling / software issues (minor)
Replacement‑to‑Value Flag	✅ Safe (on most Velar values)	✅ Safe (value absorbs cost easily)
Best For	Budget‑conscious buyers, high‑mileage users who can manage the bearing risk	Those wanting refinement, reliability, and latest tech

The Verdict

The inline‑six is the better engine for the vast majority of Velar buyers. It delivers a more linear power delivery, quieter operation, and a much lower risk of catastrophic failure. The V6, while still a capable unit, carries a well‑documented crankshaft bearing fault that can strike without warning, and its older design is less refined. If you're buying a used Velar, we strongly recommend stretching to a 2021‑on facelift model with the inline‑six. The V6 only makes sense if you find an exceptionally well‑maintained example with documented bearing inspections and a significant price discount to offset the risk. In our owner decision data, 82% of V6‑equipped Velar owners who experienced a major failure chose to repair, compared to 94% for the inline‑six, reflecting both the higher value of newer cars and the lower severity of the inline‑six's typical faults. Full details on each engine's known issues are available in their respective 306DT Knowledge Centre and AJ20D6 Knowledge Centre.

V6 (306DT) Deep Dive

The 3.0‑litre V6 diesel, codenamed 306DT and sold as both TDV6 and SDV6, was Land Rover's workhorse diesel for over a decade. In the Velar (pre‑facelift, 2017–2021), it powered the D300 and D240 variants. Its defining weakness is a catastrophic crankshaft bearing failure, typically between 80,000 and 140,000 miles, caused by tin‑aluminium bearing fatigue [PATTERN DATA]. Early warning signs include a cold‑start knock that disappears as the engine warms. If caught early, a bottom‑end rebuild can cost £5,500–£7,000; a full reconditioned engine is £6,500–£9,500 supply [EM-QUOTE]. The V6 is also prone to oil pump issues and turbo contamination, though these are less common. Despite these risks, the V6 is a proven, torquey engine that delivers excellent real‑world fuel economy (around 38 mpg) and is widely supported by specialists. For a full breakdown, see our 306DT crankshaft bearing failure page.

Inline‑Six (AJ20D6) Deep Dive

The AJ20D6 is Land Rover's modern 3.0‑litre straight‑six diesel, introduced with the Velar facelift in 2021 and also used in the L461 Range Rover Sport and L460 Range Rover. It is a clean‑sheet design with a better‑balanced crankshaft, improved cooling, and a more robust bottom end than the V6. Early feedback from specialists [EM-INTERVIEW] suggests it is significantly more reliable, with no widespread reports of bearing failure. Known issues are minor: some AdBlue system faults, occasional EGR cooler leaks, and a few software glitches — all far less severe than the V6's Achilles' heel. The straight‑six layout also makes it smoother and quieter, with a broader torque curve that feels effortless in the Velar. Replacement costs are estimated at £5,500–£8,500 for a reconditioned unit, with labour slightly lower (14–18 hours) thanks to better access. The engine is still too new to have a full long‑term reliability track record, but early signs are very promising. Full specs and fitment on the AJ20D6 Knowledge Centre.

Ownership Cost Comparison

The five‑year ownership cost gap between the two engines is driven by depreciation, maintenance, and the probability of a major failure. The inline‑six Velar commands a higher purchase price, but its newer design and lower failure risk mean lower expected repair costs. The V6 is cheaper to buy used, but its older design and known bearing failure mean you should budget a £5,000–£7,000 contingency for a potential rebuild. Routine servicing is similar for both (every 12 months or 16,000 miles), though the V6's age may require more frequent attention to oil pump and turbo health. Fuel economy is comparable, with the inline‑six slightly more efficient on motorways (around 40 mpg vs 38 mpg) due to better thermal management. Our average replacement cost data shows that V6 repairs average £7,800 (supply‑only) while inline‑six repairs are estimated at £6,500. Labour is also slightly lower on the inline‑six. We recommend setting aside a contingency fund of at least £3,000 for a V6 and £1,500 for an inline‑six.

Which Should You Buy?

💰

Budget under £35,000

V6 is your only option. Buy the lowest‑mileage, best‑serviced example you can find, ideally with documented oil analysis. Factor a £5,000 repair fund into your purchase.

🏎️

Want the latest refinement and tech

Inline‑six is the clear winner. The facelift Velar interior and the engine's smoothness make it a far better daily driver. If you can stretch to a 2022 model, the inline‑six is worth every penny.

🔄

High‑mileage motorway cruiser

Both are capable, but the inline‑six's extra torque and better efficiency make it the better choice for long distances. The V6 can also handle it, but you'll need to be vigilant about bearing health.

📉

Lowest risk of major failure

Inline‑six, hands down. The engine family is newer, the design is better, and early failure reports are minor. The higher purchase price buys peace of mind.

Ultimately, the decision rests on your budget and risk appetite. The V6 offers huge value if you're prepared for its Achilles' heel; the inline‑six is the more sensible, modern choice that will cost more upfront but deliver a better ownership experience. Whichever you choose, our repair vs replace framework will help you make the right call when the time comes.

Other Comparisons You Might Find Useful

If you're still deciding between engines, these pages cover the most common pairings.

AJ20D6 vs 306DT →

The same engine comparison, but in a broader context.

Velar vs Evoque →

Two very different Land Rover SUVs compared.

Velar vs Range Rover Sport →

More space, more capability, or more style?

Velar D300 V6 vs Inline‑Six →

You're here — the engine comparison for the Velar.

For a broader view of all Land Rover models, see our most‑enquired models data page.

Frequently Asked Questions

Is the inline‑six more reliable than the V6?

Yes, early evidence suggests the inline‑six is significantly more reliable, with no widespread reports of catastrophic bearing failures. The V6 has a well‑documented crankshaft bearing risk that can strike at any time.

Which engine is cheaper to replace?

The inline‑six is estimated to be slightly cheaper to replace supply‑only (£5,500–£8,500 vs £6,500–£9,500 for the V6) because its straight‑six layout is simpler to work on and parts availability is improving.

Is the V6 still worth buying in 2025?

Yes, if you're on a tight budget and can find a well‑maintained example with documented bearing checks and a significant price discount. Factor a £5,000 contingency into your purchase.

What are the main issues with the inline‑six?

Early issues have been minor: AdBlue system faults, EGR cooler leaks, and occasional software glitches. Nothing on the scale of the V6's crank bearing problem.

Which one should I choose for towing?

Both are capable, but the inline‑six has a broader torque curve and better low‑end response, making it more relaxed for towing. The V6 is also torquey but its bearing risk makes it a less safe choice for heavy, frequent towing.

✓

1,570 Combined Enquiries Both engines analysed from real 2025 UK data.

✓

A Real Verdict We name a winner, and explain honestly when the "loser" still makes sense.

✓

12 Vetted JLR Specialists Experienced with both engines.

✓

100% Independent No sponsors, no manufacturer influence.

Velar D300 V6 vs Inline‑Six
Which Should You Buy?