Current trends in the auto world have given quite a boost to turbocharged cars and trucks. As recently as eight years ago, they represented just 5 percent of annual U.S. sales. By last year, turbocharged engines were in 23 percent of the new vehicles sold in this country.
This trend is expected to strengthen. IHS Markit predicts that by 2024, 55 percent of all engines produced for North American drivers will be turbos.
Of course, expectations on the pre-owned side of the business are similar. What’s different is that, once turbocharged vehicles hit the used-car marketplace, many will have seen significant time on the road. In those cases, consumers will no doubt have questions about turbocharger reliability, and we’ve got some answers.
How Do Turbochargers Work?
First off, to understand the concern over potential reliability issues, it’s helpful to understand a little about what turbochargers do and how they work. Traditional internal-combustion engines burn a mixture of air and fuel for power. The actual combustion process happens in each cylinder, and the more air that can be squeezed in there, the more power will be generated.
When a turbocharger is present, exhaust gas from the engine is used to spin a small turbine wheel that, in turn, is attached to a compressor wheel. As both begin spinning together, the compressor wheel actively sucks in more air and forces it into the engine cylinders. (The other popular method of forced induction, supercharging, generally relies on a belt or chain from the engine to drive the compressor.)
Are There Any Potential Turbo Troubles?
The chief worry over turbocharged engines has to do with the incredible stresses they undergo. The exhaust gases pushing those turbine wheels, for example, can reach temperatures above 1,875 F. As for the wheels themselves, they can be spinning at 240,000 rpm (in a car like the 2015 Ford Fiesta with its optional 1.0-liter turbocharged engine). These conditions would seem to be a breeding ground for engine troubles, and in older vehicles, they often were.
Just look at one of the first turbocharged passenger cars in the United States, the 1962 Oldsmobile Jetfire. The Jetfire’s engine was delicate enough that owners had to constantly top off a separate small tank with “Turbo Rocket Fluid,” for an extra cooling measure. Also, owners worried about overheating would often keep the engine running too slowly for the turbo to kick in, and that would eventually result in the whole assembly freezing up. Needless to say, the Jetfire was off the market after 1963.
And turbo-related mechanical problems also were the primary reason that automakers gave up on the industry’s next wave of fuel-efficient turbocharged vehicles, which were introduced in the 1970s after the Mideast oil crisis.
But are Used Turbocharged Cars Reliable Today?
After 55 years of engineering progress and advances in technology, automakers have learned from their past mistakes. For instance, instead of just bolting a turbocharger onto a pre-existing engine, most companies now design the whole package at once, ensuring that all individual components can handle the added heat and stress of forced induction. New materials also have played their part, and computers have had much the same impact on engines as they’ve had on infotainment and safety technology. When it comes to turbocharged cars, that lets modern-day performance-control modules (PCMs) take over the technical business. Simply put, PCMs can precisely monitor and adjust the whole powertrain in ways that old-school mechanical setups – and forgetful owners – couldn’t match.
As a result, most experts say that current-generation turbocharged engines match their naturally aspirated counterparts for reliability. In the 2017 J.D. Power Vehicle Dependability Study, two of the industry’s key segments (Small SUV and Large Light-Duty Pickup) were won by turbo-friendly vehicles. The 2014 Volkswagen Tiguan led in the former with an all-turbo four-cylinder engine lineup, and the 2014 Ford F-150, with its popular turbocharged V6 models, came out on top in the latter.
Customers shopping for reliable used vehicles with turbocharged engines also may want to keep their eyes open for some 2017 models that will soon be headed for pre-owned status. The Honda Civic, Honda CR-V and Ford F-150 all offer turbocharged power, and they’re among the vehicles expected to surpass 200,000 miles by Consumer Reports.