IsItAGoodCar
Reliability Guide

Common Problems with the
2009 Infiniti G (G37)

The Infiniti G arrived in the UK in September 2009 as the brand's cornerstone saloon, coupe, and convertible line, powered by a 316bhp 3.7-litre V6 engine.

What changed for 2009

  • •Official UK launch of the V36 Saloon, CV36 Coupe, and HV36 three-piece metal folding hardtop Convertible
  • •Naturally aspirated 3.7-litre VQ37VHR V6 producing 316bhp and 360Nm torque with VVEL variable valve timing
  • •Choice of close-ratio six-speed manual or seven-speed automatic transmission with steering-column magnesium paddles
  • •Rear-wheel drive with standard limited-slip differential, sport suspension, and 4-Wheel Active Steer on S and S Premium trims

Common MOT watch-outs

  • !Play in front lower suspension wishbone rear compliance bushes causing steering wander and tyre wear advisories
  • !Corrosion on exhaust heat shields, rear silencer flange joints, and underbody brake lines on early UK examples
  • !Uneven brake disc wear and warped front discs causing vibration under heavy test-lane deceleration
3
Known Issues
2
Serious
1
Moderate
0
Minor

All Known Issues

VQ37VHR Rear Timing Cover Oil Gallery Gasket Rupture

SeriousEngine

On pre-2013 VQ37VHR engines, the internal oil gallery gaskets located behind the front timing cover are made of a fragile paper composite. Over heat cycles, these gaskets degrade, tear, or blow out, bleeding high-pressure engine oil internally back into the oil pan before it reaches the upper valvetrain. This causes a dramatic drop in oil pressure to the Variable Valve Event and Lift (VVEL) phasers and camshafts. If ignored, valvetrain oil starvation can cause catastrophic engine failure. Nissan later updated the part to a metal-reinforced gasket. Remediation requires an extensive front-engine teardown involving 12 to 15 hours of workshop labour to remove the front timing cover and fit updated metal gaskets.

Est. Repair Cost: £1,200–£2,200
Warning Signs:

Check engine light with stored diagnostic trouble codes P0011 or P0021 indicating intake valve timing control performance, Low oil pressure warning lamp illuminating at warm idle, Engine entering limp mode restricting engine speed below 2,500 to 3,000 RPM, Metallic valvetrain rattle or ticking sound from the upper cylinder heads when warm

What to Inspect:
  • Connect an OBD-II scanner and check for stored or pending DTCs P0011, P0021, or P0524
  • Perform a manual mechanical oil pressure test at the oil pressure switch port (warm idle should exceed 14 PSI, 2,000 RPM should exceed 43 PSI)
  • Examine service invoices to confirm whether the timing cover has been stripped and upgraded with metal gallery gaskets
Verified by IsItAGoodCar Research TeamUpdated

Heater Matrix Hose Plastic Connector Fracture

SeriousCooling System

The factory plastic heater hose coupler located against the passenger-side engine bay bulkhead degrades and becomes extremely brittle after repeated heat cycling. At higher mileages, the plastic fractures or shears completely under coolant system pressure, suddenly venting engine coolant onto the hot exhaust and ground. Because the coolant is lost within seconds, rapid engine overheating occurs. If the driver fails to shut down the engine immediately, cylinder head warping or head gasket failure can quickly follow. Replacing the fragile plastic connector with an aftermarket billet aluminium or brass barbed coupler is a standard preventative measure amongst UK specialists.

Est. Repair Cost: £150–£400
Warning Signs:

Sudden dumping of engine coolant underneath the passenger side of the vehicle, Sweet-smelling white steam billowing from behind the engine bay near the bulkhead, Engine temperature gauge needle rapidly climbing into the red zone, High coolant temperature warning light on the instrument cluster

What to Inspect:
  • Inspect the plastic heater core hose connector near the passenger-side firewall for cracking, chalking, or crusty white residue
  • Check whether the fragile factory plastic union has been upgraded to a durable brass or aluminium coupler
  • Check the coolant expansion tank level and pressure-test the cooling system for rapid pressure loss
Verified by IsItAGoodCar Research TeamUpdated

HV36 Convertible Roof Mechanism Sensor and Seal Failure

ModerateBodywork & Rust

On the G37 Convertible (HV36), the complex three-piece electro-hydraulic folding hardtop system is vulnerable to microswitch misalignment, hydraulic pump pressure loss, and weatherseal deterioration. Wear in the roof latching linkages or failed position sensors can cause the roof to stall halfway through its 25-second cycle. Furthermore, drying weatherstrips and clogged rear drainage tubes allow rainwater to seep past the C-pillar seals into the luggage compartment, soaking the boot floor carpet and short-circuiting the roof control module and the Bose audio amplifier located beneath the trim panels.

Est. Repair Cost: £400–£1,800
Warning Signs:

Folding hardtop stops moving mid-cycle and displays a roof malfunction warning on the instrument cluster, Audible chimes and refusal to unlatch or lock into the windscreen header rail, Water collecting in the spare wheel well or rear passenger footwells after rain, Damp musty smell in the cabin and intermittent sound distortion from the Bose headrest audio system

What to Inspect:
  • Operate the folding hardtop through complete open and close cycles multiple times, listening for hydraulic pump strain or hesitation
  • Inspect the boot carpet, spare wheel well, and amplifier mounting bay for signs of moisture or water staining
  • Examine the rubber seals along the roof seams and windscreen header rail for splits, flattening, or lack of lubrication
  • Pour water into the C-pillar water drainage channels to ensure water drains freely under the rear wheel arches
Verified by IsItAGoodCar Research TeamUpdated

Buying Tips for 2009 Infiniti G (G37)

  • Check that the vehicle starts crisply from cold without hesitation from the electronic steering column lock (ESCL)
  • Confirm the automatic gearbox shifts smoothly without shudders during kickdown or hesitation at low urban speeds
2010
Check a 2009 Infiniti G (G37) by Registration