Jaguar XK X150Grand Tourer2005–2014Every engine fitted to the X150 grand tourer - from the 4.2-litre AJ34 V8 and supercharged XKR to the 5.0-litre AJ133 that transformed this generation. Real UK replacement costs and honest reliability data for Jaguar's last V8-powered XK. Backed by real UK enquiries [JAG-VERIFIED].
XK Enquiries (2025)JAG-VERIFIEDGrand Tourer
6Engine Codes
Part ofEngine Finders
Every engine fitted to the X150 specifically - including the 4.2-litre AJ34 (naturally aspirated and supercharged) and the 5.0-litre AJ-V8 Gen III (AJ133) that arrived with the 2009 facelift.
Overview
The X150 is the second and final generation of the Jaguar XK grand tourer, launched at the 2005 Frankfurt Motor Show.
It succeeded the X100 and was the last V8-powered XK before the F-Type replaced it in 2014. Designed by Ian Callum, the X150 introduced an all-aluminium monocoque construction that was significantly lighter and stiffer than its predecessor. The engine line‑up was exclusively V8 petrol: the 4.2-litre AJ34 (naturally aspirated and supercharged) was carried over from the X100, replaced in 2009 by the 5.0-litre AJ-V8 Gen III (AJ133) in both naturally aspirated and supercharged forms. A 2009 facelift brought updated styling and the new engine range.
Key Facts
Platform
Jaguar X150 (all-aluminium monocoque, front-mid-engine, rear-wheel drive)
Predecessor
Jaguar XK (X100)
Successor
Jaguar F-Type
Sibling body styles in this generation
3-door fastback coupé, 2-door convertible
Market Intelligence
The XK nameplate generated significant UK engine enquiries in 2025 [JAG-VERIFIED], with the 5.0-litre AJ133 representing the majority of X150-related demand based on market patterns.
Highest Risk
5.0 AJ133 Supercharged (early pre‑2012)
“Timing chain guide wear is a well‑documented issue on early 5.0-litre AJ133 engines - the aluminium guide rails wear against steel tensioners, causing chain slack and potentially catastrophic failure. Later cars received updated tensioners.”
Who it's for: only buyers with documented timing chain work or post‑2012 cars.
Most Expensive Failure
5.0 AJ133 Supercharged (timing chain)
“Timing chain replacement on the 5.0-litre AJ133 is an engine‑out job requiring specialist tooling - £2,500–£4,500 is typical. A full engine replacement can exceed £9,000. The XKR-S and XKR-S GT are even more costly due to parts scarcity.”
Who it's for: buyers with deep pockets who want the ultimate XK.
Best Value
4.2 AJ34S XKR (supercharged)
“The 4.2-litre supercharged XKR delivers 396–416 bhp and is cheaper to buy than the 5.0-litre XKR. The supercharger adds complexity, but the 4.2's timing system is more robust than the 5.0's.”
Who it's for: buyers who want XKR performance on a tighter budget.
Highest Risk
5.0 AJ133 Supercharged (early pre‑2012)
“Timing chain guide wear is a well‑documented issue on early 5.0-litre AJ133 engines - the aluminium guide rails wear against steel tensioners, causing chain slack and potentially catastrophic failure. Later cars received updated tensioners.”
Who it's for: only buyers with documented timing chain work or post‑2012 cars.
Most Expensive Failure
5.0 AJ133 Supercharged (timing chain)
“Timing chain replacement on the 5.0-litre AJ133 is an engine‑out job requiring specialist tooling - £2,500–£4,500 is typical. A full engine replacement can exceed £9,000. The XKR-S and XKR-S GT are even more costly due to parts scarcity.”
Who it's for: buyers with deep pockets who want the ultimate XK.
Best Value
4.2 AJ34S XKR (supercharged)
“The 4.2-litre supercharged XKR delivers 396–416 bhp and is cheaper to buy than the 5.0-litre XKR. The supercharger adds complexity, but the 4.2's timing system is more robust than the 5.0's.”
Who it's for: buyers who want XKR performance on a tighter budget.
Most Overlooked
5.0 AJ133 (naturally aspirated, 385 bhp)
“Most buyers gravitate to the XKR, but the 385 bhp 5.0-litre naturally aspirated car is genuinely fast enough for the road - and it's cheaper to run, insure, and repair than the supercharged cars.”
Who it's for: buyers who want modern XK performance without supercharger running costs.
The X150 rule
A £5,500–£9,000 5.0 XKR recon against a £15,000–£25,000 XKR sits at 22–60% of the car's value - at the upper end, that brushes our 60% Jaguar scrap threshold. Against a £20,000+ example, the same recon drops to 28–45% - a repair decision, not a scrap question. For a 4.2 XK at £10,000, a £3,500–£6,000 recon is 35–60% - borderline but often viable for a well‑kept example. Value the car first; if it's a pre‑2012 5.0 without timing chain history, walk away or budget for the work immediately.
Key Takeaways
Which X150 Costs Least To Own?
4.2 AJ34 (naturally aspirated) - simple, robust, no supercharger complexity.
Which X150 Costs Most To Own?
5.0 XKR-S GT - timing chain work is engine‑out, parts are scarce, and running costs are eye‑watering.
Which X150 Is Best Value?
5.0 AJ133 (naturally aspirated, 385 bhp) - modern power, no supercharger, cheaper to buy and run than the XKR.
5.0
AJ133 Timing Chain Guide Wear
Affected models:
Typical failure mileage:
Root cause:
Our Recommendation
If you're buying a pre‑2012 5.0-litre X150, look for documented timing chain work or budget £2,500–£4,500 immediately. A preventative chain and tensioner replacement is dramatically cheaper than the £5,500+ replacement that follows a failure. On a car worth under £15,000, evaluate carefully before committing.
4.2
AJ34 / AJ34S Cooling System & Thermostat Housing
Affected models:
Typical failure mileage:
Root cause:
Our Recommendation
Have the cooling system inspected at every service - a £400–£800 preventative thermostat housing and water pump replacement is far cheaper than the £3,500+ replacement that follows an overheat. On a car worth over £10,000, this is a straightforward repair decision.
Supercharger
Coupler Wear (AJ34S & AJ133 508PS)
Affected models:
Typical failure mileage:
Root cause:
Our Recommendation
If your XKR develops a rattling noise from the supercharger area, have the coupler inspected immediately - a £500–£1,000 coupler replacement is far cheaper than the £4,500+ supercharger rebuild that follows a failure. On a car worth over £20,000, this is a manageable cost of ownership.
Electrical
Gremlins (All X150s)
Affected models:
Typical failure mileage:
Root cause:
Our Recommendation
Before chasing electrical faults on an X150, check the battery voltage first. A weak battery (below 12.4V) can cause a cascade of warning lights that disappear with a new battery. If you're buying an X150, budget for a new battery immediately.
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£4,500–£7,500 (reconditioned, supply only)
[JAG-QUOTE]
Most Common Failures
Live FeedJaguar XKR X150
5.0 AJ133
3
enquiries
Jaguar XK X150
4.2 AJ34
2
enquiries
Jaguar XKR X150
4.2 AJ34S
2
enquiries
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£4,500–£7,500 (reconditioned, supply only)
[JAG-QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£4,500–£7,500 (reconditioned, supply only)
[JAG-QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£4,500–£7,500 (reconditioned, supply only)
[JAG-QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£4,500–£7,500 (reconditioned, supply only)
[JAG-QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£4,500–£7,500 (reconditioned, supply only)
[JAG-QUOTE]
Most Common Failures
Live FeedJaguar XKR X150
5.0 AJ133
3
enquiries
Jaguar XK X150
4.2 AJ34
2
enquiries
Jaguar XKR X150
4.2 AJ34S
2
enquiries
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