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Diesel engines are a tough sell in the United States, particularly since the 1970s when General Motors converted a gas V-8 to run on diesel for its Oldsmobile brand, which resulted in woeful reliability issues (mainly head bolts that couldn’t withstand the rigors of diesel compression). The 2001 introduction of GM’s powerful and stout Duramax diesel V-8 in its heavy-duty trucks—the result of a joint venture with Isuzu—helped make up for that earlier, ill-fated effort with Olds. But perhaps even more compelling for drivers who don’t need near-big-rig levels of torque is the recent addition of a light-duty Duramax inline-six, which debuted in the Chevrolet Silverado 1500 and GMC Sierra 1500 pickups and has now begun to spread to all of GM’s redesigned full-size SUVs, the first of which is the latest Chevy Tahoe tested here.

HIGHS: Smooth and refined operation, impressive highway fuel economy, minimal price increase.

The turbocharged 3.0-liter Duramax is one of three engines available in the new Tahoe. Base models get a 355-hp 5.3-liter V-8, while the top-spec High Country is powered by a standard 420-hp 6.2-liter small-block. The diesel is the least powerful of the group, at 277 horsepower, but its 460 pound-feet of torque is the same as the 6.2’s. Diesel engines are usually a costly upgrade because, among other reasons, they incorporate expensive exhaust-treatment systems that keep their sootier emissions in check. But that’s not the case here. In High Country trims like our test vehicle, the diesel comes with a $1500 credit versus the big V-8. On lesser models, the engine is but a $995 line item and the cheapest Tahoe with the Duramax starts at $53,295; a loaded High Country starts at $69,395. Just be mindful that optional equipment can greatly inflate those starting figures, as exemplified by the $80K-plus price of our well-equipped example.

Michael SimariCar and Driver

A diesel’s prodigious torque output often implies a massive benefit for towing. But the 3.0-liter Duramax is rated to tow the least weight of the Tahoe’s powertrains, although its still-strong 8200-pound rating in rear-drive models is but 200 pounds less than that for Tahoes equipped with the 5.3-liter V-8 and the optional Max Trailering package. The diesel also has an available trailering package, but it doesn’t alter the truck’s maximum capacity. If you’re worried about a 200-pound buffer when towing, you probably need a more capable rig.

LOWS: Slower than gas V-8s, reduced towing capacity, noticeable cowl shake over broken pavement.

Where the six-cylinder Duramax shines is in its fuel efficiency. Based on current prices for fuel and diesel exhaust fluid—and assuming the EPA’s combined estimates for rear-wheel-drive models of 18 mpg for the 5.3 and 23 mpg for the diesel—the Tahoe’s Duramax option would pay for itself in about 80,000 miles. That break-even point is largely realistic, and it will shrink with the more miles spent on the interstate. We averaged 27 mpg on our 75-mph highway fuel-economy test, which is enough to give the diesel Tahoe a bladder-busting range of more than 600 miles. We haven’t had the opportunity to test the highway legs of a Tahoe equipped with the 5.3-liter, but a GMC Yukon with the 6.2 got 20 mpg in the same test. Overall, our four-wheel-drive Chevy averaged 23 mpg.

Michael SimariCar and Driver

Opting for the Duramax doesn’t greatly impact the Tahoe’s drivability. Mated to a standard 10-speed automatic transmission that shuffles its gears swiftly and smoothly, our 6100-pound test truck reached 60 mph in 7.8 seconds. Models with the 5.3-liter V-8 are about a second quicker to that mark, and 6.2-liter versions are significantly fleeter still. But that performance deficit is only an issue if you regularly visit the shortest of short highway onramps. Similarly, the diesel’s 6.1-second pull from 50 to 70 mph is mostly adequate in the real world, even if it lags behind the 4.7-second time we recorded for the 5.3.

While older diesels often struggle to supply heat to the cabin in freezing temperatures, this 3.0-liter employs the latest coolant-control strategy to cope with frigid air. The Duramax’s engine computer can control flow to the engine block, head, transmission cooler, oil cooler, cabin heater, and low- and high-pressure exhaust-gas recirculation coolers. This allows the engine to quickly send warm coolant to the cabin heater. After sitting overnight in below freezing conditions, our test truck’s climate control started blowing warm air in less than three minutes into our drive. Plus, if all else fails, there is a resistance heater that produces warm air for the cabin.

Michael SimariCar and Driver

Although the 3.0-liter Duramax is far more refined than diesels from just a decade ago—and even some modern ones—there’s no mistaking its clattery idle as coming from anything but a compression-ignition engine. Our truck’s 42-decibel sound reading at idle and 68 decibels at a 70-mph cruise are louder than a 5.3-liter Tahoe’s by 2 and 3 decibels, respectively. But we never found its noise levels to be intrusive when behind the wheel.

As with all of GM’s new big SUVs, the diesel Tahoe features an independent rear suspension, which opens up more room for passengers and improves its ride quality compared to the previous solid-rear-axle setup. No one buys a Tahoe for its handling dynamics, but the new truck can hustle down a back road surprisingly well, although its cowl and steering column do shake more than we’d like over rough pavement. Combined with the new model’s much improved interior quality and design versus even the latest Silverado 1500 and Sierra 1500 pickups, the redesigned Chevy Tahoe pairs exceedingly well with what is one of GM’s best diesel engines ever.

Specifications

Specifications

2021 Chevrolet Tahoe Duramax 4WD

VEHICLE TYPE
front-engine, rear/4-wheel-drive, 7-passenger, 4-door wagon

PRICE AS TESTED
$80,840 (base price: $53,295)

ENGINE TYPE
turbocharged and intercooled DOHC 24-valve diesel inline-6, aluminum block and head, direct fuel injection
Displacement
183 in3, 2993 cm3
Power
277 hp @ 3750 rpm
Torque
460 lb-ft @ 1500 rpm

TRANSMISSION
10-speed automatic

CHASSIS
Suspension (F/R): control arms/multilink
Brakes (F/R): 13.5-in vented disc/13.6-in vented disc
Tires: Bridgestone Alenza A/S 02, 275/50R-22 111H M+S TPC Spec 3156MS

DIMENSIONS
Wheelbase: 120.9 in
Length: 210.7 in
Width: 81.0 in
Height: 75.9 in
Passenger volume: 178 ft3
Cargo volume: 25 ft3
Curb weight: 6100 lb

C/D TEST RESULTS
60 mph: 7.8 sec
100 mph: 24.0 sec
Rolling start, 5–60 mph: 8.7 sec
Top gear, 30–50 mph: 4.3 sec
Top gear, 50–70 mph: 6.1 sec
1/4 mile: 16.0 sec @ 85 mph
Top speed (governor limited): 112 mph
Braking, 70–0 mph: 170 ft
Roadholding, 300-ft-dia skidpad: 0.53 g
Standing-start accel times omit 1-ft rollout of 0.3 sec.

C/D FUEL ECONOMY
Observed: 23 mpg
75-mph highway driving: 27 mpg
Highway range: 640 miles

EPA FUEL ECONOMY (C/D EST)
Combined/city/highway: 24/21/28 mpg

C/D TESTING EXPLAINED

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