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McLaren 720S Common Problems: What the Second-Gen Super Series Teaches Us
Independent McLaren Service — Foreign Automotive × Thorney Motorsport — Kitchener, Ontario
MCLAREN 720S COUPE • SPIDER
McLaren 720S Common Problems: What the Second-Gen Super Series Teaches Us
Folding cluster motors, HVAC blower modules, active aero — what second-generation Super Series teaches us.
The 720S was a clean-sheet redesign of McLaren's Super Series. Built 2017–2023, it dropped a new 4.0L M840T twin-turbo V8 making 710 hp, a revised Monocage II carbon tub, redesigned active suspension, and a chassis that finally made the car feel as fast as the numbers said it was. Roughly 5,500 720S Coupes and Spiders were built across the run. The car has been on the road long enough now that its reliability patterns are clear, and they are different from the first-generation Super Series cars in important ways.
Here is what we see on 720S cars in our shop, and what we would tell any 720S owner or prospective buyer to watch for.
Folding instrument cluster motor failure
The 720S has a folding instrument cluster — the binnacle physically pivots to a low-profile orientation in Track mode and back upright in normal driving. The motor that drives the fold is a small geared unit, and on cars from 2017–2019 production we see the motor gears stripping or the position sensor failing. Symptoms: the cluster gets stuck in one position, will not fold on mode change, or makes an audible buzz when it tries to move but does not actually move.
The fix is access to the cluster mechanism behind the dash trim. The motor is a serviceable assembly. This is one of those repairs that is mechanically straightforward but labour-intensive — getting access requires partial dash disassembly, and the trim panels on a 720S are not designed for repeat removal. We do this job a few times a year.
Door handle motor failure
The 720S uses the same general pop-out door handle design as the rest of the McLaren range. Failure modes are identical: handle does not extend (locked out from outside), or handle extends but does not retract. The 720S handles are slightly more exposed to road spray than earlier cars due to the body design. We are seeing failures starting around year five. Pair replacement, every time.
Dihedral door strut failure
The 720S Coupe doors are heavier than the Sport Series doors. The strut design is also revised, with higher-rated gas pressure. The five-to-seven-year service window applies, but failures within that window can be more dramatic on the 720S because the heavier door drops harder when the strut gives up. We have seen body panel damage from dropped doors on 720S cars that we have not seen on lighter 570S doors. Replace the struts as a pair, on schedule.
Hydraulic accumulator pressure loss
The 720S uses an updated hydraulic system architecture compared to the 12C/650S, with revised valving and improved isolation between circuits. But it still uses a nitrogen-precharged accumulator, and that accumulator still loses pre-charge with age and heat exposure. On 2017–2019 cars we are now in the active replacement window.
The 720S adds a complication: the active suspension on this car (Proactive Chassis Control II) uses hydraulic accumulator pressure differently than the first-generation Proactive Chassis Control. When the accumulator pre-charge drops on a 720S, the first symptom is often a slight degradation in suspension behaviour over rough surfaces — a hesitation in damping response — rather than the obvious gearbox or nose-lift symptoms. By the time a 720S owner notices "the suspension feels different," the accumulator is well into its failure window.
Carbon ceramic brake disc rebound
This is more an owner education item than a service item. The 720S comes standard with carbon ceramic brakes. Carbon ceramic discs are durable but they do not respond well to corrosion in storage, and the 720S has a tendency to develop a specific rebound issue where the brake pedal feels long and soft after the car has been sitting for more than two or three weeks. The cause is the carbon ceramic piston seals relaxing slightly in storage, allowing a small amount of fluid back-bleed.
The fix is a brake pedal exercise routine: with the car off, pump the brake pedal twenty to thirty times to re-seat the piston seals before the first drive after storage. After about ten kilometers of normal driving the pedal feel returns to normal as the system equalizes. We do not consider this a fault, but we do consider it information that 720S owners are rarely told at delivery.
Active aero airbrake hesitation
The 720S's active aero is a refinement of the system used on the 675LT, with revised actuator geometry. The actuator is more robust than the earlier design. We see far fewer airbrake failures on 720S cars than on 650S or 675LT cars at equivalent ages. The remaining failures are mostly software-level — the deployment logic occasionally gets confused by ABS events at the same instant — and resolve with firmware updates.
Coolant hose connector hardening (Gen 2)
McLaren revised the coolant hose connector design on the 720S to address the hardening and cracking issues that plagued earlier cars. The new connectors are more robust, but the 2017–2018 production used some connectors from the previous generation as the parts supply transitioned. We have seen a small number of coolant connector failures on early 720S cars. We pressure-test at every service.
Air conditioning blower module fault
This is a 720S-specific issue we see more often than is documented elsewhere. The blower motor controller module can fail intermittently, producing symptoms that look like a complete HVAC failure: no air flow on any setting, no fault code visible on the cluster (the fault logs to the IRIS system and the body control module rather than to the engine ECU). Customers will sometimes spend a few hundred dollars chasing imagined IRIS or refrigerant faults before the actual cause is identified.
The fix is a controller module replacement. The part is accessible from the passenger footwell. We always check the blower controller as a stored-fault item on 720S inspections.
Sport Pack steering rack vagueness
720S cars optioned with the Sport Pack received a stiffer steering rack ratio. We have a small number of customer 720S cars with the Sport Pack that have developed a slight on-centre vagueness in steering feel around 60,000–80,000 km. The cause is wear in the rack mounting bushings rather than the rack itself. The fix is bushing replacement; we have not had to replace a rack on a 720S.
Battery management on a hybrid-compatible architecture
The 720S is built on an architecture that anticipated McLaren's hybrid program (which arrived with the Artura). The 720S is not a hybrid, but the battery management protocols are more aggressive on this car than on earlier McLarens. A weak battery on a 720S will produce more dashboard warnings and module faults than the same battery on a 570S. Tenders, again, are non-optional for any 720S that sits more than a week between drives.
Why a PPI on a 720S still matters
The 720S is more reliable than the first-generation Super Series cars on most measures. That does not mean a used 720S deserves less inspection — it means the inspection looks for slightly different things. We look for: storage damage on low-mileage cars, evidence of track use (the 720S is a popular track-day car), accident repair on a carbon tub car (which can be done extremely well or extremely badly), the specific 720S-only fault codes that live in the body control module rather than the engine ECU, and stored data from the chassis modules showing actual use patterns.
A proper 720S PPI is a four-hour appointment with diagnostic time on a McLaren-specific tool that reads all modules, not just the engine. We have inspected 720S cars at $260,000 in pristine condition and we have inspected 720S cars at $280,000 that had been repaired after a low-speed collision in a way that compromised the front structure. The carbon tub on these cars is repairable, but the repair quality is everything.
Service intervals on a 720S
The McLaren annual service framework, 1st through 15th services. Identical structure to the rest of the lineup:
- 1st Service: Annual or first 10,000 km. Oil and filter, basic consumables.
- 2nd Service: Year two. Oil, filter, brake fluid flush, cabin filter, engine air filters.
- 3rd Service: Minor — oil and filter only.
- 4th Service: Major — oil, filter, brake fluid, cabin filter, air filters.
- 5th Service: Year five. Oil, filter, full coolant flush.
- 6th Service: Major plus fuel filter and charcoal canister.
- 10th and 12th Services: Major plus fuel and charcoal filter, plus brake system bleed.
The 720S is approaching the 6th-service window for the earliest cars. The fuel filter and charcoal canister replacement at this interval is the item most commonly skipped, and the symptoms of a neglected charcoal canister will eventually catch up with the car as evaporative system fault codes.
Where we fit in
The 720S is McLaren's most polished car prior to the Artura. It rewards proper service and it punishes neglect on a faster timeline than the first-generation Super Series cars did. We are the only authorized McLaren independent specialist in Canada outside the dealer network, partnered with Thorney Motorsport in the UK, and we service the 720S to the same factory-specification standards used by McLaren itself.
If you own a 720S in Ontario, or you are evaluating one, book a McLaren service or pre-purchase inspection. We will tell you what is wrong, what is right, and what we would do if it were our car.
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The only authorized McLaren independent specialist in Canada outside the dealer network.
Service, repair, pre-purchase inspections — to McLaren factory specification, partnered with Thorney Motorsport in the UK. We will tell you what is wrong, what is right, and what we would do if it were our car.
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