You’ll want to avoid the 2003, 2005, and 2006 Infiniti G35 model years, which have documented high failure rates and numerous recalls. The 2003 models suffer from crankshaft sensor failures and valve cover leaks, while 2005-2006 models face severe powertrain issues and excessive oil consumption. Your safest bets are the 2007-2008 models, which offer improved reliability and fewer repairs. Understanding specific mechanical weak points can help you evaluate potential purchases more effectively.
Most Problematic G35 Model Years
Three model years stand out as particularly troublesome for the Infiniti G35: 2003, 2005, and 2006. Based on owner experiences and market trends, the 2005 model faced severe powertrain issues and suspension wear, leading to increased maintenance costs and reduced resale values. You’ll find similar problems in the 2006 model, which struggled with camshaft position sensor failures and electronic malfunctions that caused engine stalls and power loss.
Both years exhibited suspension component failures by 100,000 miles, requiring costly repairs to rotors and axles. While 2004 models showed better reliability overall, they weren’t immune to problems. The mid-2000s G35s consistently required more frequent repairs and higher maintenance expenses compared to later models, with documented issues affecting everything from engine performance to interior electronics. The 2008 model year proved to be a significant improvement with 4.5 out of 5 reliability ratings from J.D. Power.
Understanding the 2003 G35’s Major Reliability Issues
The 2003 Infiniti G35 presents a distinct set of mechanical challenges that owners should monitor closely. You’ll need to watch for crankshaft and camshaft position sensor failures that can cause stalling and starting problems, directly impacting engine performance. These sensor upgrades are often necessary to maintain reliable operation. Regular throttle body cleaning every 20,000 miles helps prevent unstable idle issues. Like the engine knocking issues reported in later QX50 models, the G35 requires careful monitoring.
Your suspension system requires particular attention, as front lower control arm bushings wear prematurely. Consider upgrading to polyurethane bushings for improved durability. You’ll also encounter common electrical issues, including window motor failures and faulty door lock actuators. The cooling system demands vigilance – replace thermostats at recommended intervals to prevent overheating. While the VQ35DE engine can surpass 200,000 miles with proper maintenance, you’ll need to address timing chain tensioner wear and potential guide rail issues promptly to guarantee longevity.
Critical Problems With 2005-2006 Models
While many G35 models exhibit typical aging issues, 2005-2006 variants stand out for their significant mechanical and electrical vulnerabilities. You’ll encounter frequent engine stalling issues stemming from faulty crankshaft and camshaft sensors, along with increased oil consumption problems that can damage your engine if left unchecked.
The sensor failure frequency extends beyond engine components, affecting door locks, window motors, and instrument clusters. Installing an oil catch can may help reduce consumption issues, though it won’t eliminate them completely. Similar to fuel pump failures in other vehicles, these electrical problems can lead to unexpected stalling. You’ll need to watch for transmission concerns, particularly in manual models where third gear grinding is common. Much like the early IS300 models, power steering problems can develop unexpectedly. The suspension system demands attention too, with premature bushing wear causing handling problems and unwanted vibrations.
Regular inspection of valve cover gaskets and coolant bleeder valves is essential, as these components often fail, leading to oil leaks and potential overheating situations.
The G35’s Most Reliable Years: 2004 and 2007-2008
Among G35 model years, 2004 and 2007-2008 stand out as reliability champions, exhibiting robust VQ engines capable of surpassing 200,000 miles with proper maintenance. While the 2004 model faced early brake wear issues requiring service every 10,000-15,000 miles, Infiniti implemented significant brake improvements in 2007-2008, extending pad and rotor longevity. Regular maintenance yields an impressive 26 MPG highway efficiency for these model years.
You’ll encounter minor electrical concerns across these years, including window motor malfunctions and sound system quirks, but they’re less frequent than in other model years. The 2007-2008 models particularly refined these electrical systems. Similar to the strong V6 engines found in later QX70 models, these G35 years delivered excellent performance. Unlike the M37’s timing chain issues that plagued later Infiniti models, these G35 years proved mechanically sound. Despite some cosmetic issues like headlight oxidation, these model years deliver exceptional drivetrain durability. Though replacement parts aren’t cheap, their quality construction contributes to the vehicle’s long-term reliability and performance potential.
Common Mechanical Failures Across All Years
Regardless of model year, G35 owners frequently encounter sensor-related problems that can wreak havoc on engine performance. Common mechanical issues include faulty camshaft and crankshaft sensors, triggering error codes like P0340 and causing drivability concerns. Much like the RAV4’s ECM problems, sensor failures can lead to expensive transmission repairs.
You’ll also need to watch for valve cover gasket leaks, which allow oil to seep into spark plug tubes and damage ignition coils. The timing chain system presents another critical issue, with worn tensioners and guides potentially leading to catastrophic engine failure if left unchecked. Frequent sensor failures aren’t your only concern – you’ll likely face electrical gremlins affecting dashboard instruments and fuel gauge readings. The suspension system’s various bushings, particularly in the control arms and differential, will deteriorate over time, impacting your vehicle’s handling and stability. Double clutching transmissions can help prevent grinding noises when shifting gears, especially in third gear.
High Mileage Performance and Longevity
Three key factors determine your G35’s longevity at high mileage: maintenance history, driving conditions, and component wear patterns. With proper care, you’ll find DE-series engines capable of surpassing 200,000 miles, with many reaching 300,000. For ideal performance tuning at high mileage, monitor your fuel system components, particularly the mass airflow sensor and spark plugs, as their degradation directly impacts engine efficiency.
Longevity tips include addressing suspension wear early, especially control arm bushings, which often require aftermarket upgrades. Manual transmissions tend to fare better long-term, though automatics remain reliable with proper maintenance. Watch for HVAC and electronic issues, particularly in 2003-2004 models, as these components often require attention beyond 150,000 miles. Regular fluid changes and proactive parts replacement will maximize your G35’s lifespan. The 2005-2007 manual transmission models commonly develop oil consumption issues that should be monitored closely.
Engine Reliability and Maintenance Requirements
Several key reliability differences exist between G35 model years, with 2003-2004 VQ35DE engines showing better overall durability compared to the 2005-2007 “rev-up” variants. You’ll find the later models consume more oil due to worn piston rings, requiring frequent monitoring and top-offs between services.
While monitoring oil levels is critical across all years, you’ll need to pay extra attention to the rev-up engines, as they’re prone to excessive consumption that can impact engine performance. With proper maintenance routines, many G35s continue performing reliably beyond 230,000 miles. Watch for timing chain rattling and failed crankshaft angle sensors, which are common issues affecting drivability. Regular maintenance should include checking timing components, valve cover gaskets, and spark plug tube seals. Installing an oil catch can might temporarily help manage oil vapor, but won’t solve underlying piston ring wear in 2005-2007 models.
Cost Analysis: Repairs and Maintenance by Year
Understanding repair costs across G35 model years reveals distinct spending patterns that align with known mechanical issues. You’ll face the highest repair frequency with 2003 models, averaging $500 annually, while 2005-2006 models also demand significant maintenance budgeting. Early models particularly struggle with control arm bushings and suspension components requiring premature replacement. The 2003 model year was especially problematic with seven major recalls, making it the most troublesome year for owners.
When planning your maintenance budget, note that 2007-2008 models typically incur lower costs. However, all G35s need consistent attention to oil changes, filters, and gaskets for ideal longevity. After 100,000 miles, expect increased expenses for electronics and engine sensors, especially in pre-2005 models. While brake jobs remain consistent across years, the 2005 G35X specifically shows higher costs for axle and rotor repairs beyond the 100,000-mile mark.
Critical Recalls and Safety Concerns
Safety recalls plagued multiple G35 model years, with the 2005-2007 vehicles facing particularly serious airbag system defects. The recall impact affected 135,000 vehicles due to faulty wire harnesses that could prevent proper airbag deployment during crashes. The NHTSA awaited remedy from Nissan regarding the airbag issue. You’ll find the highest concentration of safety assessments focused on 2004-2006 models, which suffered from brake light switch malfunctions preventing proper illumination when braking.
Earlier G35s from 2002 encountered fuel pump hose connection issues that could lead to engine stalling and fire risks. Similar to the Ford Edge’s inflator ruptures, these airbag system problems required urgent manufacturer attention. The 2004-2005 period proved especially problematic, with complaint volumes peaking at 297 and 244 respectively. If you own an affected model, you should contact Infiniti customer service, as these safety-critical issues required immediate attention through federally-mandated recall programs.
Recommended Model Years for Used Car Buyers
Three key model years stand out when evaluating used Infiniti G35s for purchase: 2007-2008 models offer the highest reliability ratings and fewest repairs, while 2004 models present a sweet spot of durability and value.
When conducting model comparisons, you’ll want to target G35s with under 120,000 miles and complete service records. The 2007-2008 models benefit from upgraded variable valve timing and improved suspension components, resulting in better long-term durability. Expect to spend around $10,000 for a well-maintained manual transmission model. If you’re considering a 2004 model, inspect for front lower control arm bushing wear, though these vehicles commonly reach 270,000 miles with proper maintenance. Buyer tips: avoid 2003 models due to crankshaft sensor issues and high recall counts. Consider 2006 models only if they have documented maintenance history and polyurethane bushing upgrades.
