The Infiniti Q30 is a premium compact built on the Mercedes-Benz W176 A-Class platform, assembled at the Nissan Sunderland plant. The 1.5d is the entry diesel: 109 hp, front-wheel drive, with a 6-speed manual or the optional 7-speed DCT. Powered by the widely used Renault K9K 1.5 turbodiesel, it delivers economical and comfortable motoring in a distinctive design that stood out from the German mainstream. Infiniti ended its European commercial activities on 31 March 2020, so servicing, warranty repair and parts support now run through an authorised repairer network rather than a dealer network.· more· less
Economical, proven K9K diesel engineMercedes platform, parts widely available
No Infiniti dealers, only authorised repairersCoil spring breakage widely reported
Buy if: You want an uncommon premium compact with cheap diesel running costs and can source parts through Mercedes or Nissan channels.
Avoid if: You rely on a dense manufacturer dealer network or need guaranteed parts availability for insurance repair estimates.
Maintenance costs
€850 – €1,600/year
at 15,000 km/year
Fixed costsservice, tyres, brakes€550 – €950 /yr
Risk bufferunplanned repairs€300 – €650 /yr
Price estimates are based on German asking prices. Prices and costs vary by vehicle condition and location.
Maintenance costs
Maintenance assumes 15,000 km a year. Price estimates are based on German asking prices. Prices and costs vary by vehicle condition and location.
K9K diesel particulate filter clogs when driven predominantly on short urban trips · more· less
The K9K engine's DPF requires periodic passive regeneration during sustained motorway driving at higher exhaust temperatures. Frequent short trips under 15-20 km prevent regeneration, causing soot buildup that triggers the DPF warning light and can lead to limp mode. A forced regeneration at a workshop costs €150-300. If the DPF is too heavily blocked for regeneration, professional cleaning runs €400-600, while full replacement costs €800-1,200 including fitting. This issue is common across all K9K applications (Renault, Nissan, Dacia, Mercedes) and is not Q30-specific. Regular motorway runs of 30 minutes or more significantly reduce the risk.
EGR valve and intake carbon buildup
€300 - 6002 of 6
Exhaust gas recirculation valve accumulates carbon deposits, causing rough running and power loss · more· less
Carbon buildup in the EGR valve and intake manifold is a well-documented K9K issue, typically appearing between 80,000 and 120,000 km. Symptoms include rough idle, hesitation under acceleration, engine management warning light, and occasionally juddering in higher gears. EGR valve replacement costs €300-500 at an independent specialist. Intake manifold cleaning adds €100-200 if the carbon buildup has extended into the ports. Some owners opt for periodic EGR cleaning during scheduled services to prevent complete blockage, which is significantly cheaper at €80-150.
Turbo actuator sticking / turbocharger wear
€500 - 1,5003 of 6
Variable-geometry turbo actuator sticks from carbon deposits, causing power loss and limp mode · more· less
The K9K's small variable-geometry turbocharger can develop sticking actuator issues, particularly in cars driven gently at low RPM in urban conditions. Carbon deposits on the vanes restrict movement, causing intermittent power loss, engine management warning light, and limp mode. A turbo actuator clean at a specialist costs €200-400. If the turbo bearings are worn or the actuator is seized, full turbo replacement costs €800-1,500 including fitting. Forum owners have reported engine management light and limited top speed as symptoms. Using the engine through its rev range occasionally helps prevent carbon buildup.
7G-DCT dual-clutch gearbox wear (if equipped)
€1,500 - 3,5004 of 6
Mercedes 724.0 7G-DCT can develop clutch wear, jerkiness, and mechatronics faults · more· less
Q30 models with the optional 7-speed DCT automatic share the Mercedes 724.0 gearbox. Common issues include cold-start jerkiness and shudder at low speeds, typically improving after 10-15 minutes of driving. More serious failures involve clutch pack wear and mechatronics unit faults, usually between 60,000 and 100,000 km. The DCT filter must be changed on schedule; neglecting this restricts oil flow and accelerates clutch wear. Clutch replacement costs €1,500-2,500, while mechatronics repair runs €2,000-3,500. Manual gearbox Q30s avoid this issue entirely. Forum discussion suggests Infiniti calibrated the DCT slightly better than Mercedes, but the underlying hardware weaknesses remain.
Coil spring breakage
€300 - 8005 of 6
Rear and occasionally front coil springs crack and break, shared with the Mercedes W176 platform · more· less
Multiple Q30 and QX30 owners report broken coil springs, primarily at the rear. This issue is also documented on the Mercedes W176 A-Class and GLA X156 that share the same suspension design. Springs typically fracture at a corrosion point, often without warning, and a broken spring can damage the tire or inner wheel arch. A single spring replacement costs €150-300 per corner at an independent garage. The complication with the Q30 is parts sourcing: some owners have reported waiting months for Infiniti/Nissan supply. Using Mercedes-Benz equivalent springs (same design) can speed up the process and reduce cost. Replacing both springs per axle when one breaks is recommended.
Injector seal leak at high mileage
€200 - 6006 of 6
Copper injector seals deteriorate over time, allowing exhaust gas to leak around injectors · more· less
The K9K's copper injector washers gradually lose their seal, typically after 120,000-180,000 km. When a seal fails, hot exhaust gases leak around the injector, leaving a distinctive black carbon crust on the cylinder head around the affected injector. If caught early, replacing the copper washers is straightforward and costs €100-200 in parts and labor. If left unattended, carbon buildup can damage the injector seat in the cylinder head, requiring more extensive work that pushes costs to €500-600. Early detection during routine servicing prevents escalation.
Reliable drivetrain, but orphaned brand adds ownership complexity
The K9K 1.5 diesel is one of the most widely produced diesel engines in Europe and is fundamentally durable when properly maintained. Most issues are standard diesel wear items (DPF, EGR, turbo actuator) that any diesel specialist can handle. The main Q30-specific concern is parts availability: Infiniti ended its European commercial activities on 31 March 2020 and now covers servicing, warranty repair and parts through an authorised repairer network, so some body-specific or electronic components may need sourcing through Nissan or using Mercedes W176 equivalents. Some insurers have reportedly had difficulty valuing Q30s or sourcing parts for repair estimates, occasionally leading to write-offs on otherwise repairable damage. Manual gearbox variants are simpler and more reliable than DCT-equipped cars.
Service history
Complete records from an authorised Infiniti repairer, Nissan, or an independent specialist essential. Verify oil changes every 12 months or 15,000 km and timing belt replacement history.
Tires
Check tread depth, age (date codes), and uneven wear patterns indicating suspension issues.
Cold start
Start engine completely cold. Listen for unusual rattling, knocking, or excessive diesel clatter.
Test drive
Minimum 20 minutes including motorway speeds to check for DPF regeneration behavior and turbo response.
Specific for this vehicle
Check for DPF warning light or reduced power
Drive for at least 20 minutes. If the DPF light illuminates or power drops noticeably, the filter may be heavily blocked. Ask when the last successful regeneration occurred.
Listen for turbo whistle or hesitation under load
Accelerate firmly from low speed in third gear. The turbo should spool smoothly without hesitation, unusual whistling, or engine management warnings.
Inspect all four coil springs for cracks
Look closely at each coil spring for surface corrosion, hairline cracks, or visible fractures. Rear springs are most commonly affected. A broken spring may cause the car to sit unevenly.
+ 4 more checksShow less
Verify all recall work completed via Nissan
Contact Nissan or an authorised Infiniti repairer with the VIN to confirm every listed campaign has been completed, including the EU steering shaft campaign PG1CF/PG1CQ. The airbag, seat belt and steering shaft campaigns are particularly important.
Test 7G-DCT gearbox if automatic
Drive for at least 15 minutes. Check for excessive jerkiness at low speeds, hesitation between gears, or shuddering during gentle acceleration. Cold-start jerkiness is common but should diminish as the gearbox warms. If it persists once warm, have the transmission checked by an Infiniti repairer or a qualified workshop before buying.
Inspect cylinder head around injectors
Open the bonnet and look at the top of the engine around each injector. Black carbon crust indicates a leaking injector seal that needs attention.
Confirm parts supply route
Ask the seller or a local specialist whether they can source Q30-specific parts. Mercedes W176 A-Class equivalents fit many suspension and drivetrain components. Body panels and interior trim are harder to source.
Recalls and Technical Service Bulletins
EU campaign PG1CF/PG1CQ: defective lower steering shaft joint can cause loss of steering control (2016-2017 build Q30 and QX30)Critical - verify completed
UK DVSA campaign: driver's airbag may deploy unintentionally due to grounding fault (Jan 2016 - Jul 2017 build)Critical - verify completed
UK DVSA campaign: passenger airbag may not deploy correctly due to manufacturing defect (Aug - Sep 2016 build)Critical - verify completed
UK DVSA campaign: rear seat belt buckle nuts may not be fully secure (Aug 2015 - Jul 2016 build)Verify completed
UK DVSA campaign: front seat belt anchorage incorrectly positioned (Mar 2015 - Mar 2016 build)Verify completed
UK DVSA campaign: airbag control unit configuration error (Oct 2015 - Feb 2017 build)Verify completed
UK DVSA campaign: gear shift indicator display fault, software update (Mar 2015 - Aug 2018 build)Verify completed
Campaign PG1CF/PG1CQ was notified in Germany for the EU and covers 2016-2017 H15 cars; it is the safety-critical one, because a defective lower steering shaft joint can cause loss of steering control. The six campaigns below it are the UK DVSA Q30 campaigns and may not have been run in every European market. Infiniti ended its European commercial activities on 31 March 2020, but servicing, warranty repair and parts support continue through its authorised repairer network, and Nissan handles recall obligations for Infiniti vehicles in Europe. Contact Nissan or an authorised Infiniti repairer with the VIN to verify the work has been completed. The steering shaft, airbag and seat belt campaigns must be confirmed before purchase.
Warranty Status
Factory warranty (3 years / 100,000 km)Expired on all Q30s
Infiniti sales and service networkSales ended 31 March 2020, servicing via authorised repairers
Recall and parts obligationsHandled by Nissan as parent company
All Q30s (2015-2019) are outside their original factory warranty. Infiniti ended its European commercial activities on 31 March 2020, but servicing, maintenance, warranty repair and parts support continue through an authorised repairer network, and Nissan, as the parent company, handles outstanding recall obligations and parts supply. Third-party extended warranties may be available, but verify the insurer can source Q30-specific parts before purchasing coverage.
Sources: Research draws on model-specific owner forums and owner communities, recall information from official authorities, German automotive press, and multiple workshop cost references cross-checked against each other.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.
