- Handsome design
- Inexpensive base model
- Spacious rear compartment
- Capable handling
- 31-mile plug-in hybrid range
- Firm ride, all the time
- Missing a few luxury amenities
- Driver's seat won't suit some
- No V-8, but who will want a 2.0-liter four?
- Can Cadillac market a plug-in hybrid?
The 2018 Cadillac CT6 has the style and performance to match its German rivals, but is the brand there yet?
The 2018 Cadillac CT6 is the full-size sedan flagship of GM’s luxury brand. It’s a car GM hopes will move it closer to being viewed as competition for the German luxury trio of Audi, BMW, and of course Mercedes-Benz.
With the CT6, Cadillac combines a spare, elegant, and distinctive design with a lightweight body, excellent handling and roadholding, and a plug-in hybrid model that beats the Germans decisively on range. Its four trim levels are base, Luxury, Premium Luxury, and Platinum.
For 2018, the CT6 adds a SuperCruise adaptive cruise control option that allows hands-off driving. Other changes are minor, including the addition of gas and brake pedal operation to the Park Assist feature, and a few new paint colors. The CT6 Plug-In arrived late in the 2017 model year, though its sales are focused on California and just a few other states.
With the full model range now in place and SuperCruise soon to arrive, we’ve rated the CT6 a 7.8 out of 10. It wins points for sleek lines, a roomy and comfortable back seat, surprisingly good handling, and the plug-in hybrid’s prowess. (Read more about how we rate cars.)
2018 Cadillac CT6
The 2018 Cadillac CT6 is the brand’s most sophisticated design, but you have to see it in person to appreciate it.
The 2018 Cadillac CT6 has to be seen in person to be appreciated properly. The big sedan has the same design cues as the CTS, which is 8.5 inches shorter, but the bigger car stretches them over a longer body. It’s low, broad-shouldered, and muscular.
In its crisp lines and linear accents, the CT6 is the polar opposite of the soft, fluid curves of a Mercedes. It uses straight edges and flatter surfaces rather than arcs and swells in a shape that pairs a long hood with a high waist and large wheels. The vertical LED headlights run up and over the top of the fender, while Cadillac’s signature vertical taillights distinguish it at the rear. The broad grille has its own textured cross-hatching and a large, confident Cadillac crest.
It all comes together distinctively, and it lets the CT6 stand proud of its German competitors with a look all its own. Our score of 8 out of 10 rewards the distinctive exterior and an excellent interior, one that scores for its relatively simplicity and straightforward character. (Read more about how we rate cars.)
Inside, while other makers fill their cars with technology (Audi) or extravagant comfort (Mercedes), the CT6 finds its own balance of luxe and clarity. Think of it as a Mies Van Der Rohe building among its 1930s contemporaries. It’s chillier than the stunning cabin of the S-Class, which speaks to the senses as well as the functional parts of the brain, but it’s far away from the bling of its truck-like big brother, the Escalade, as well. There’s satin chrome, stained wood, and slim carbon-fiber accents, with fine leather to sit in and touch.
The shape of the dash plays up the car’s width, with a broad character line running from side to side. The center peak of the hood is echoed in the top of the dash, while the center touchscreen is framed in a shape that recalls the grille outline. It could be heavy-handed, but it’s not. Overall, the interior comfortable, functional, and expertly crafted—if not quite as distinctive as the exterior.
2018 Cadillac CT6
The 2018 Cadillac CT6 handles as well as most Europeans, with ample power from its twin-turbo V-6 or the longest-range plug-in hybrid luxury sedan.
Following its smaller siblings, the CT6 gets the latest of Cadillac’s expertise in advanced materials and engineering. It has one of the stiffest and lightest bodies in its class, giving it taut roadholding, fast acceleration, and enjoyable driving in general.
We’ve scored the CT6 at 8 points out of 10 for its variety of engines—now including the plug-in hybrid—excellent transmission, and handling prowess. There’s no high-performance “V” model, however, meaning Cadillac leaves a yawning gap in its lineup against rivals’ AMG or M versions and loses a point accordingly. (Read more about how we rate cars.)
Lighter weight, less engine needed
When the CT6 launched in 2016, it offered three direct-injected engines, from the 265-horsepower 2.0-liter turbo-4 through a naturally aspirated 335-hp 3.6-liter V-6 up to the hot rod of the line, a new 404-hp 3.0-liter twin-turbo V-6. All transmit power the rear wheels through an 8-speed automatic, with all-wheel drive optional on the two V-6s.
Last year they were joined by the Plug-In version, which pairs a high-efficiency version of the 2.0-liter 4-cylinder to a two-motor hybrid transmission and a 17.6-kilowatt-hour lithium-ion battery pack behind the rear seat. Made in China, the plug-in CT6’s 31-mile rated range is about double that of similar models from BMW and Mercedes-Benz.
The shell of the CT6 blends several types of high-strength steel and aluminum, which Cadillac claims makes it lighter than a similar structure entirely in aluminum, which would need far more sound deadening material to be competitive. The base model is just 3,657 pounds, even less than German competitors one size smaller and 1,000 pounds less than an S-Class. Move up to the top CT6, with its twin-turbo V-6 and all-wheel drive, and you’re still below 4,100 pounds.
Fast and stable
The lean nature of the CT6 is best demonstrated in the 2.0-liter, rear-drive base model. It’s light on its feet, more agile than heavier versions, and has good power despite only four cylinders. It will sprint from 0 to 60 mph in 6.1 seconds, Cadillac says, and we deem it the most fun to drive.
On the power end of the scale, the 3.0-liter V-6 with its twin turbochargers cuts that acceleration figure to 5.3 seconds and delivers passing power at any speed. The bigger engine and all-wheel drive give it more weight on the front wheels, though, making it understeer more when pushed through corners. The electric steering is well weighted in all modes, and works well with a suspension that can border on overly stiff. No matter which driving mode you dial up, from Tour to Sport, the CT6 always rides firmly.
Optional magnetic dampers and active rear steering are part of an optional Active Chassis package. The magnetic dampers give it a firm grip on body motion, but competitors’ air dampers offer more range in tuning, from sport-sedan firm to cushy cruiser, at the flick of a switch. The CT6’s 3.5 degrees of rear-wheel steering may make parking lots a bit easier, but it’s still a long, large car despite its agility. That means it’ll never be as lively or sporty as the best of the mid-size sedans below it.
2018 Cadillac CT6
Comfort & Quality
The 2018 Cadillac CT6 has plenty of rear-seat room, but it’s not as comforting or plush as the best luxury models.
The cabin of the Cadillac CT6 is the finest and most modern the brand has ever offered, and high-quality materials abound. Against the best of the German large luxury sedans, it comes across as less refined—simply because those are some of the finest interiors in the best cars on the planet.
For its comfort, quality, and utility, the CT6 gets 8 points out of 10 for fit and finish, a vast and spacious rear seat, good interior storage, and surprising cargo space. On the minus side, the front seats aren’t as comfortable as those in some competitors, and the center seat in the rear barely qualifies as a position. (Read more about how we rate cars.)
Part of the challenge is that Cadillac’s esthetic for trim and interior design is pure and spare. Think of it as a Barcelona chair, perhaps. At the same time, some of the German uber-sedans have become unexpectedly evocative and emotionally appealing. Against the S-Class, with elegant round chrome vents and lush ambient lighting, or the Audi A8 with its sandwiched metal-and-wood trim, the CT6 lacks warmth. The materials are superbly fitted; it’s the luxury, the cosseting character that’s absent.
The driver’s seat is a luxurious command perch, but it’s both firm and flat. It could be improved either by more bolstering or softer cushions; while Cadillac is at it, they could add more range of motion to the power adjustments to accommodate 95th-percentile drivers, though those with long legs will be happy no matter how tall they are.
The rear seats are the best in the house, though: passengers get plentiful head room and leg room so plentiful it might suit NBA players. A top-end executive package adds reclining and even massaging to the sculpted outer rear seats, and 10-inch displays on the backs of the front seats for the pampered passengers. (A minor quibble: the CT6's rear seat belt receptacles are mounted low, and they're hard to find and use, especially when the center armrest is down.)
The center position is better used for a large fold-down console; any third rear-seat rider essentially sits on top of the bump for the transmission tunnel.
The 15.3-cubic-foot trunk can swallow quite a lot of cargo, but a rear center pass-through doesn’t compensate for the lack of folding rear seatbacks. The trunk of the CT6 Plug-In, however, is notably compromised, with a footlocker-size battery sitting behind the rear seat, cutting cargo volume to 10.6 cubic feet.
2018 Cadillac CT6
The 2018 Cadillac CT6 hasn’t been rated for crash safety; its electronic safety systems will add hands-off SuperCruise mode this year.
Because neither the NHTSA nor the IIHS has rated the Cadillac CT6 for crash safety, we’re not awarding it a safety rating in our own scoring system. (Read more about how we rate cars.)
The CT6 will be a safety pioneer this year, when GM launches its SuperCruise hands-off adaptive cruise control that will steer as well as accelerate and brake as needed. While the company had hoped to bring it in a year or two earlier, extra safety checks and the procedures to alert drivers when the car required them to retake control took some extra time.
Until SuperCruise arrives, the CT6 is one of only a few GM vehicles to offer the innovative rear camera monitor, which flips from your basic standard mirror to a display for a rear-facing camera that gives a full-width image on the mirror glass. While the CT6 has good outward vision, the display shows a field three times as wide as the usual view through the sedan’s rear window. We found it took some training to get used to (and made it harder to judge how close the following car really is). For 2018, Cadillac has added a washer to keep its camera lens clear.
The CT6 otherwise comes with the usual suite of airbags, traction and stability controls, and a standard rearview camera. Also standard, except on the base model (where it’s optional), is a package that combines forward-collision warnings, lane-departure warnings and active lane control, and blind-spot monitors.
Various safety options and packages include automatic emergency braking, adaptive cruise control, and automatic parking assist that now operates the pedals as well as the steering. A set of surround-view cameras can record front and rear video while the car is traveling, or a complete 360-degree view if the driver activates the car’s security system when parked. A Teen Driver system that limits certain vehicle functions for specific drivers is a new addition for 2018.
2018 Cadillac CT6
The base 2018 Cadillac CT6 is a luxury bargain, and its high-end models overlap with pricier German contenders.
While the 2018 Cadillac CT6 has many excellent technology features, none of them really transforms the class. The one exception may be the SuperCruise hands-off adaptive cruise control system that will arrive during this model year; read Motor Authority's coverage of the system. The CT6 gets extra points above for its standard and optional features, as well as for its infotainment system, though there are some qualifications on that last one. (Read more about how we rate cars.)
The CT6 is sold in base, Luxury, Premium Luxury, and Platinum models. The base car’s 2.0-liter turbo-4 powers only the rear wheels. The top three trim levels offer the choice of a 3.6-liter V-6 or a 3.0-liter twin-turbo V-6, with optional all-wheel drive. All versions include leather, heated front seats with a power adjustable driver’s seat, power adjustable steering wheel, dual-zone climate control, 18-inch alloy wheels, and a rearview camera.
The Driver Awareness and Convenience Package standard. It comes with forward-collision warnings with automatic emergency braking; blind-spot monitors; lane-departure warning and active lane control; and a panoramic sunroof. It’s an option for the base model, but standard on all other trims.
The Luxury trim adds niceties like 16-way power adjustable front seats, an automatic heated steering wheel, and a 10-speaker version of the Bose audio system. Above that, the Premium Luxury model ventilates the front seats, heats the rear seats, and adds a larger 12-inch digital gauge cluster, a head-up display, the rear camera mirror (with a new camera washer this year), and 19-inch alloy wheels.
Options and infotainment
A lengthy list of options include an active chassis system with magnetic adjustable dampers, rear-wheel steering, and 20-inch wheels. More extravagant is the rear-seat executive package—developed, we suspect, for Chinese buyers as much as North Americans—that bundles a host of luxe features. Those include power reclining and massaging rear seats that are both heated and cooled, rear climate controls, a center armrest with media controls, HDMI input, wireless headphones, and twin 10-inch entertainment screens on the backs of the front seats.
The top audio system is a $3,700 Bose Panaray with 34 speakers, though we didn’t find it to give quite the sound quality with uncompressed audio files that the newest Burmester or Bang & Olufsen setups do in luxury competitors.
The CT6 Platinum model dispenses with options altogether, including every package listed above plus a Driver Assistance with Night Vision Package. Still, the CT6 lacks the broad range of trim options and customized interiors offered by the best of the German brands. While Cadillac is working hard on its dealer experience, CT6 buyers don't get the valet service of Hyundai's fledgling Genesis brand. They do get free maintenance for three years, in addition to a 4-year, 50,000-mile bumper-to-bumper warranty.
Finally, a word on the CT6 infotainment system. Every version includes a Bose audio system with eight speakers, OnStar 4G LTE with a wi-fi hotspot, satellite radio, three USB ports, Bluetooth connectivity, and wireless mobile phone charging. The CUE interface now uses a 10.2-inch touchscreen in the center of the dash. We’ve given the car a point for this system not for the embedded CUE software, but because Apple CarPlay works almost flawlessly. The CT6 is one of few luxury sedans to offer the Apple conduit for safe smartphone usage (the Mercedes E-Class is another). Once you’ve used CarPlay, or perhaps its Android Auto counterpart, to send text messages by voice or to locate a destination, it’s clear why the simple, stripped-down interface is easier to use than virtually any interface supplied by a carmaker. Even for luxury cars, less can be more.
2018 Cadillac CT6
The 2018 Cadillac CT6 is unusual in offering a 4-cylinder model, though the plug-in hybrid is clearly the fuel-economy champ.
For 2018, the Cadillac CT6 large luxury sedan offers four separate engines, from a 2.0-liter turbo-4 rated at 265 horsepower to a 3.0-liter twin-turbo V-6 putting out 404 hp.
The 2.0-liter has the best fuel efficiency of the three conventional engines, at 22 mpg city, 30 highway, 25 combined. The 335-hp 3.6-liter V-6, likely to be the most popular engine, comes in at 18/27/21 mpg. Buyers who opt for the high-performance turbocharged 3.0-liter V-6 and all-wheel drive will see 18/26/21 mpg, according to the EPA.
For fuel economy, however, the big news is the CT6 Plug-In, which uses a version of that same 2.0-liter inline-4, an 18.4-kilowatt-hour lithium-ion battery pack, and a pair of electric motors similar to those used in the Chevrolet Volt. Total combined power is 335 hp, making it both a quick and fuel-efficient luxury sedan, and EPA ratings of 25 mpg combined when operating as a hybrid and 62 MPGe while running on battery power, which gives a rated electric range of 31 miles.
Like other plug-in hybrids, it’s virtually impossible to say what kind of gas mileage any individual driver will get. That all depends on how often the car is plugged in and how it’s driven. But the plug-in model will be a very low-volume vehicle—1,000 units a year or less—largely targeted to California and a few other regions, and the base 4-cylinder likely won’t sell in high numbers either. So the 2018 Cadillac CT6 gets an overall green rating of 7 out of 10 for its volume models. (Read more about how we rate cars.)