The Lemon Index
McLaren's 4.0 L twin-turbo 90° flat-plane V8 in the 720S / 750S and GT, model years 2018–2022. YouTube likes the 2021 best.
A safer bet: YouTube owner tone 54/100, #36 of 165 engines with a YouTube study (in the top third); 1 engine-related recall on record.
Reliability by year
Not enough complaints to chart. Owners filed 3 complaints with the government that we can tie to this engine's cars, 2018–2022, about any part of the car. Supercars sell in small numbers, so we show YouTube, recalls and the automaker's repair notes instead.
YouTube videos are most positive about the 2021 (57) and least about the 2018 (52); neighboring years share many of the same videos, so small gaps mean little.
How we count: owner complaints only where the car's name and year leave no doubt; YouTube tone from videos that name this engine or its cars. How we count
Owner complaints (NHTSA) are filed by model and year, not engine. We count one for this engine only when the model name and year had no other engine (e.g. "488 GTB", "GT-R"), or when the owner's own words name a version that had only this engine that year (Z06, ZR1, Hellcat, GT500 ...). They cover the whole car (wheels, air bags, electrics ...), not only the engine, and none of them is a failure rate. We chart them only for engines with 30 or more, over 3 or more years. YouTube tone = how positive the videos are, 0–100, from titles and transcripts (praise vs trouble words, the title counts 3 times), weighted by views; a year needs at least 3 videos' worth. A video counts for this engine when its title names the engine or a car that only had this engine in the years it names; a video whose title names no model year counts toward every year of that car, so neighboring years share most of their videos.
All the numbers, year by year
| Year | Cars | Owner complaints | YouTube says | Recalls |
|---|---|---|---|---|
| 2018 | 720S / 750S | 1 | 52 (83 videos) | 0 |
| 2019 | 720S / 750S | 1 | 52 (83 videos) | 0 |
| 2020 | 720S / 750S, GT | 1 | 54 (104 videos) | 5 |
| 2021 | GT, 720S / 750S | 0 | 57 (164 videos) | 3 |
| 2022 | 720S / 750S, GT | 0 | 56 (155 videos) | 2 |
Recalls on cars with this engine 5
1 of them is about the engine, fuel, cooling or powertrain. They come first.
20V231000 Fuel System, Gasoline · McLaren GT 2020
The Noise, Vibration, and Harshness (NVH) foam pad underneath the fuel tank may retain moisture and corrode the fuel tank, potentially causing a fuel leak.
25V216000 Service Brakes, Hydraulic · McLaren 720S / 750S, McLaren GT 2020–22
The brake lines may be routed incorrectly and cause the brakes on the incorrect side to activate, possibly resulting in one of the rear wheels locking up.
24V661000 Latches/Locks/Linkages · McLaren GT 2020–22
The manual release cable of the hood latch may have excessive tension that can cause the latch to open, resulting in the hood opening unexpectedly.
22V103000 Air Bags · McLaren GT 2020–21
The driver's air bag and the occupant restraint controller may be improperly connected, which can result in a deactivated driver's air bag that will not deploy in a crash.
21V561000 Service Brakes, Hydraulic · McLaren GT 2020
The brake assembly banjo bolt may be missing the holes that supply brake fluid to the caliper, which would cause the brakes to fail on one corner of the vehicle.
NHTSA recalls by model and year. A recall counts here when every confirmed version of that model-year had this engine, or the recall names it. Check a car's VIN for its own open recalls.
Engine problems McLaren told dealers about
McLaren sent dealers 22 repair notes about the engine on these cars, including:
- Engine System Fault Warning Message - Fuel System Adaptions
- Turbo Wastegate Rattle
- Engine Oil Leak Detection Dye
NHTSA manufacturer communications (technical service bulletins), matched by model name and year like the complaints, engine-related ones only. A repair note is not a recall: ask a seller whether it was done.
Every US version with this engine
| Car and versions | Years |
|---|---|
| McLaren 720S / 750S 720S Coupe, 720S Coupe LM, 720S Spider, 765LT Coupe, 765LT Spider | 2018–22 |
| McLaren GT GT | 2020–22 |
Engine codes: M840T (720S, 765LT), M840TE (GT). Assembled by Ricardo in Shoreham-by-Sea, UK. Power: 612–755 hp, factory figures. Versions and years: EPA (fueleconomy.gov). Sources: McLaren M840T engine · McLaren GT.
Quick answers
What cars have the McLaren M840T engine?
In the US: the McLaren 720S / 750S, McLaren GT, model years 2018–2022. See the version table for each one.
Is the McLaren M840T reliable?
Mostly yes. YouTube owner tone 54/100, #36 of 165 engines with a YouTube study (in the top third); 1 engine-related recall on record. Not enough owner complaints to judge it per car: supercars sell in small numbers. Its cars had 5 recalls (1 about the engine, fuel or powertrain). Have any used car inspected.
How much horsepower does the McLaren M840T make?
612–755 hp in factory figures, depending on the car.