The 5.0 V8 Supercharged Timing Chain Issue Explained

The Jaguar/Land Rover AJ133 5.0-litre V8 is one of the most characterful engines in modern motoring. In supercharged form, it produces up to 575bhp and a glorious exhaust note. But there's a well-documented weakness hiding behind those cylinder heads — and if left unchecked, it can destroy the engine.

The AJ133 5.0 V8 Engine

First used in 2009, the AJ133 replaced the older AJ-V8 in everything from the Range Rover and Range Rover Sport to the Jaguar F-Type R and XJR. It's an all-aluminium, direct-injection V8 available in both naturally aspirated (375-385bhp) and supercharged (510-575bhp) forms.

The engine uses four timing chains — two primary and two secondary — driven from the crankshaft. These chains are tensioned by hydraulic tensioners that rely on engine oil pressure to maintain the correct tension. It's a well-proven design used across many manufacturers, but the specific tensioners JLR used in early production have a known weakness.

The Timing Chain Tensioner Problem

The original timing chain tensioners fitted to pre-2012 5.0 V8 engines have a design flaw in their ratchet mechanism. The ratchet is designed to prevent the tensioner from collapsing when oil pressure drops (such as during engine shutdown). In the original design, the ratchet can fail to hold, allowing the tensioner to collapse partially.

When you next start the engine, the slack chain can jump one or more teeth on the camshaft sprocket before oil pressure builds and the tensioner extends. This causes a momentary but catastrophic mis-timing event. In the best case, you hear a brief rattle on start-up. In the worst case, the valves meet the pistons.

"The tragedy of the 5.0 V8 timing chain issue is that it's entirely preventable. The updated tensioners and chains cost a fraction of what an engine rebuild does. The key is doing it before the first rattle."

Symptoms and Diagnosis

Timing chain issues on the 5.0 V8 present in a predictable pattern:

• Cold start rattle: A brief metallic rattle lasting 1-3 seconds on the first start of the day. This is the chain slapping against the guides before oil pressure builds. If you hear this, do not ignore it — book it in immediately.
• Fault codes for camshaft correlation: The engine management system monitors camshaft position relative to crankshaft position. If the chain has jumped a tooth, you'll get correlation fault codes (P0016, P0017, P0018, P0019).
• Rough idle and reduced power: If the timing is out by one or more teeth, the engine will idle roughly and feel noticeably down on power. The ECU may enter a limp mode.
• Complete engine failure: In the worst scenario, the chain jumps enough teeth that valve-to-piston contact occurs. This typically bends valves and can score cylinder bores. At this point, you're looking at a complete engine rebuild or replacement.

The Fix: Our Approach

JLR released updated tensioners (revision C and later) that address the ratchet mechanism weakness. At Nine Torque, our timing chain replacement service is comprehensive:

1. Pre-Job Diagnostics: We assess the current state of the engine using SDD, checking for camshaft correlation codes and measuring actual vs. desired camshaft positions.
2. Full Chain Kit Replacement: We replace all four timing chains, all four tensioners (with the latest revision), all chain guides, and all sprockets. We don't do half-measures — if you're in there, replace everything.
3. Updated Tensioner Design: We only fit the latest revision tensioners with the improved ratchet mechanism. We also verify the part numbers against JLR's latest technical bulletin to ensure we're fitting the current specification.
4. Camshaft Timing Verification: After assembly, we use our specialist timing tools to verify all four camshafts are timed correctly to the crankshaft. This is checked against factory specifications to the degree.
5. Post-Job Diagnostics and Test: A full diagnostic reset, adaptation learn, and extended road test. We verify all camshaft correlation values are within specification and no fault codes return.

The job typically takes 2-3 days and requires the removal of the front of the engine (bonnet, radiator, intercooler, and front covers). It's a significant job, but done properly with the correct parts, it's a permanent fix that gives the engine another 100,000+ miles of reliable service. Browse our JLR model guides or contact us to discuss your vehicle.