The Infiniti FX35 is a mid-size luxury crossover SUV built on the Nissan FM platform and sold in the U.S. market from model year 2003 through 2012. It was produced in two generations and offered in rear-wheel-drive and all-wheel-drive configurations.
Engine timing system identification matters for maintenance planning and for used-vehicle assessments. Both engines used across the FX35’s production run belong to Nissan’s VQ V6 family, and both use a timing chain rather than a rubber timing belt.
Understanding the specific engine and its timing components helps owners determine appropriate service schedules and assess long-term engine reliability. The engine code changed between generations, and each version has distinct timing system hardware.
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Does the Infiniti FX35 Have a Timing Belt or Timing Chain?
Every U.S.-market Infiniti FX35, from 2003 through 2012, uses a timing chain. Both the VQ35DE (2003–2007) and VQ35HR (2008–2012) engines are interference designs. No timing belt service applies to any FX35 model year.
2012 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35HR) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | Final model year of the FX35 nameplate; revised grille and fascia for 2012; engine unchanged |
The 2012 FX35 is the last model year to carry the FX35 name in the U.S. The VQ35HR uses a three-chain timing system. Regular oil changes at the manufacturer-specified interval are the primary maintenance requirement for chain and tensioner longevity.
2011 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35HR) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | Same timing system as 2012; no powertrain changes from 2010 |
Same timing system as 2012. The VQ35HR in the 2011 FX35 produces 303 hp and uses a timing chain with no published replacement interval. Chain condition is best assessed by monitoring for cold-start noise and maintaining consistent oil service.
2010 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35HR) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | Same timing system as previous model year; 303 hp at 6,800 rpm |
Timing system unchanged from 2011. The VQ35HR uses hydraulic tensioners to maintain chain tension on all three chains. Cold-start chain rattle on high-mileage 2010 models is often related to tensioner wear or oil condition.
2009 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35HR) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | First full model year of the second-generation S51 platform; 7-speed automatic introduced |
The 2009 model year launched the second-generation FX on the redesigned S51 platform. The VQ35HR engine and its timing chain configuration carried over from the 2008 transition year. No timing belt service applies.
2008 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35HR) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | Engine upgraded from VQ35DE to VQ35HR; timing chain system architecture differs from prior generation |
The 2008 FX35 introduced the VQ35HR, replacing the first-generation VQ35DE. Both engines use timing chains, but the chain kits are not interchangeable. The VQ35HR was re-engineered with revised camshaft profiles and higher redline capacity while retaining the interference design.
2007 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35DE) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | Final model year of the first-generation S50 platform; XM satellite radio added as standard |
The 2007 FX35 is the last model year of the first-generation platform. The VQ35DE uses one primary timing chain connecting the crankshaft to the intake camshafts, and two shorter secondary chains connecting the intake and exhaust camshafts on each bank. No timing belt service applies to any 2007 configuration.
2006 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35DE) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | Mid-cycle facelift for 2006; leather seats and rearview camera became standard; engine unchanged |
Same timing system as 2007. The 2006 model received a significant equipment upgrade but no powertrain changes. The VQ35DE’s three-chain timing system remained unchanged from prior model years.
2005 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35DE) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | Dark chrome grille and accent trim added for 2005; no changes to engine or timing system |
Timing system unchanged from 2006. On the VQ35DE, timing chain tensioner guides are a documented wear point at higher mileage. Rattle on cold start that diminishes after oil pressure builds warrants inspection of the tensioner and guide condition.
2004 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35DE) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | Eight-way power front passenger seat added as standard; engine and timing system unchanged from 2003 |
Same timing chain configuration as 2005. The VQ35DE uses Nissan’s Continuous Variable Valve Timing Control (CVTC) on the intake camshafts, driven by the timing chain system. No timing belt service applies to the 2004 FX35.
2003 Infiniti FX35 Timing Belt Or Timing Chain
| Specification | Detail |
|---|---|
| Engine Option | 3.5L V6 (VQ35DE) |
| Timing System | Timing Chain |
| Interference Engine | Yes |
| Replacement Interval | Lifetime (no scheduled replacement) |
| Maintenance Notes | Launch year; first-generation S50 platform; 5-speed automatic; 280 hp at 6,200 rpm |
The 2003 FX35 is the launch model year for the nameplate. The VQ35DE uses a three-chain timing system: one primary chain from the crankshaft to the intake camshaft sprockets, and two secondary chains linking the intake and exhaust camshafts on each cylinder bank. No timing belt applies.
Timing Belt vs Timing Chain on the Infiniti FX35
A timing belt is a rubber-reinforced external drive component that synchronizes crankshaft and camshaft rotation. It operates dry and degrades over time regardless of mileage, requiring replacement at manufacturer-specified intervals, typically between 60,000 and 105,000 miles.
A timing chain accomplishes the same engine timing function using metal links running on sprockets inside the engine. The chain is continuously lubricated by pressurized engine oil and does not have a published replacement interval under normal operating and maintenance conditions.
The Infiniti FX35 uses a timing chain exclusively across all production years. The maintenance difference is significant: no scheduled replacement interval applies, but the chain system depends entirely on oil quality and pressure. A degraded or contaminated oil supply accelerates wear on the tensioner, guides, and chain links.
Timing chain warning symptoms include a persistent rattling or slapping sound during cold starts that fades once oil pressure stabilizes. On the VQ35DE specifically, worn chain guides are a documented cause of timing noise. Timing chain repair on the FX35 requires significant engine access and typically costs more than a timing belt replacement on comparable vehicles.
Infiniti FX35 Timing System Maintenance
The FX35’s VQ35DE and VQ35HR engines carry no published timing chain replacement interval. Under normal operating conditions and consistent maintenance, the chain system is rated to last the engine’s service life. Owners should not budget for scheduled timing chain service the way belt-driven engine owners must.
Audible rattling from the engine front on cold starts is the primary symptom of a worn timing chain system on the FX35. On the VQ35DE, chain guide wear is the most common underlying cause. This noise typically diminishes within a few seconds as oil pressure builds and tensioners hydraulically load the chain.
Engine oil quality directly affects the timing system on both VQ35 variants. Both engines specify 5W-30 engine oil. Extending oil change intervals or using incorrect viscosity reduces oil pressure to the hydraulic chain tensioners and accelerates guide wear. Consistent oil maintenance is the most effective preventive measure available.
Timing chain inspection is warranted on any FX35 with documented deferred oil maintenance, persistent cold-start noise, or mileage above 150,000 miles. Chain stretch, tensioner plunger travel, and guide condition can be assessed by a qualified technician without full engine disassembly in some cases, though complete access requires front cover removal.
| Timing Belt | Timing Chain |
|---|---|
| Rubber; external; dry operation | Metal; internal; oil-lubricated |
| Scheduled replacement required | No scheduled replacement interval |
| Not used on any FX35 engine | Used on all FX35 model years (2003–2012) |
| Lower replacement labor cost | Higher repair cost when worn |
| Failure risk if interval exceeded | Wear accelerated by neglected oil maintenance |
Frequently Asked Questions
Does the Infiniti FX35 have a timing belt or timing chain? Every Infiniti FX35 uses a timing chain. The VQ35DE engine covers 2003–2007 model years, and the VQ35HR covers 2008–2012. Neither engine uses a timing belt.
When should the timing chain be replaced on an Infiniti FX35? No replacement interval is published for either VQ35 engine. Chain replacement is typically needed only when wear symptoms such as persistent cold-start rattling appear, often at very high mileage.
Is the Infiniti FX35 an interference engine? Yes. Both the VQ35DE and VQ35HR engines in the FX35 are interference engines. A timing chain failure can cause valve-to-piston contact and severe internal engine damage.
What are the symptoms of a worn timing chain on an Infiniti FX35? The most common symptom is rattling or slapping from the engine front during cold starts. On the VQ35DE, worn plastic chain guides are a frequent cause. Noise that persists at operating temperature is a more urgent concern.
How much does Infiniti FX35 timing chain replacement cost? Timing chain replacement on the FX35 typically ranges from $800 to $2,000 or more depending on labor rates and whether guides, tensioners, and seals are replaced at the same time. Dealer costs generally exceed independent shop pricing.
Did the timing system change between generations of the FX35? Yes. The first generation (2003–2007) uses the VQ35DE, and the second generation (2008–2012) uses the VQ35HR. Both use timing chains, but the chain kits and hardware are not interchangeable between the two engines.
Conclusion
The Infiniti FX35 uses a timing chain for every U.S. model year from 2003 through 2012. The VQ35DE engine covers the first generation (2003–2007) and the VQ35HR covers the second generation (2008–2012). Both are interference engines with lifetime-rated chain systems and no scheduled replacement interval.
Timing chain condition on high-mileage FX35 models depends heavily on oil maintenance history. Always verify timing system details using the owner’s manual or manufacturer service information before scheduling repairs.
