Are today’s turbocharged engines more reliable?

Many years ago, my wife bought a new Ford with a turbocharged engine. It ran fine for a number of years but then had a major engine failure due to a stuck waste gate. Ever since, I have been a little negative regarding turbocharged engines. Now, however, turbocharged engines are offered by every carmaker, and I do not seem to read much about engine failures or even a lack of reliability. What’s your take on this? Is it time for me to reset my thoughts on this issue? — Jim P.

Yes! Things have changed quite a bit since the turbocharged engines of the 1980s. Modern turbocharged engines are designed from the ground up to be used with a turbocharger. Engine parts that are subjected to the increased stress of turbocharger operation are beefed up and are typically trouble-free. Turbochargers themselves have also evolved with better bearings, better cooling, and better lubrication in addition to improved metallurgy. The way that a turbocharger is controlled has changed a lot also. Instead of primitive mechanical waste gate controls, there are now a bevy of sensors reporting engine and environmental conditions to the powertrain control module, or PCM, so turbocharger operation can be carefully managed. If conditions such as hot and dry air, a lean air-fuel ratio, or engine ping are encountered, turbo boost is reduced, along with other possible protective actions.

Turbocharger surge, a condition that can occur during sudden throttle closure, can whipsaw intake pressure enough to damage the turbo. But it can now be mitigated with additional controls. Variable-rate turbochargers are also popular, allowing a larger turbocharger to act like a smaller one at lower speeds and spool up more quickly. This improves torque across a wider rpm range, which really enhances drivability.

The stuck waste gate you encountered with the older Ford would today be identified, and the PCM can take action to alternately reduce turbocharger boost by limiting engine rpm. If needed, the PCM can also order up reduced ignition timing and increased exhaust gas recirculation (EGR) flow rate to mitigate the effects of excessive boost. This helps keep the piston tops from becoming volcanic craters.

I’ve read close to a dozen quotes by car company powertrain engineers claiming modern turbocharged engines are just as reliable as naturally aspirated ones, and speaking with folks who actually fix them seems to largely confirm this. This isn’t to say one can skate on maintenance. Turbocharged engines are more demanding on engine oil and work harder pound-for-pound than a larger naturally aspirated engine making similar power. I’d have no problem owning one and giving it the maintenance respect it deserves.

I just traded in the electric Fiat — loved that car but the lease was up and I was ready to try something new. I’m now learning the ropes of a ’17 Chevy Volt, a different spin on EVing. I’ll be sure to report on how it goes after getting settled in.