Many people believe that turbocharged 3-cylinder engines are bad. While there are good examples out there, there’s one that reinforces the stereotype, and that’s the Ford EcoBoost 1.0-liter turbo, offered to American buyers in the EcoSport subcompact crossover as well as the Focus.
The 1.0-liter EcoBoost is also known as the Ford Fox and has been available in Europe since 2012 starting with the Focus and Fiesta. However, it wasn’t offered in North America until much later. The Focus received a 1.0-liter 3-cylinder during the 2015 refresh as an added-cost option (to the 2.0-liter) for the SE trim. Its most important role was in the 2018-2022 EcoSport, a subcompact crossover.
The early 1.0-liter EcoBoost engines in Europe were quite problematic, specifically from 2012 to early 2015 ones. The Ford powertrain received the nickname “EcoBoom” because they blow the coolant pipe which destroys the engine because there’s no dashboard light telling you there’s a problem. For the most part, these issues were addressed by Ford during a recall, and that doesn’t necessarily affect American 1.0-liter EcoBoost engines.
However, the other main issue of the 1.0-liter EcoBoost does appear in this teardown video from “I Do Cars” a popular YouTuber specializing in diagnosing broken engines.
Timing belt bathed in oil timing
The 1.0-liter has a timing belt or cambelt, whatever you want to call it. That’s not unusual, many small engines have that. Belts generally don’t last as long as chains, but cheap cars like the EcoSport generally don’t put in a lot of miles.
What’s unusual is that the 1.0-liter EcoBoost has a timing belt that’s submerged or bathed in oil. From a mechanical engineer’s point of view, that sounds like a really bad idea. Most if not all manufacturers avoid their engine belts ever being touched by oil. Not Ford.
In theory, the oiled belt is a good idea because it’s supposed to last longer, as much as 10 years or 150,000 miles according to some maintenance guides we found in Europe. However, people either don’t serve the car regularly or they use the wrong kind of oil, which is to be expected on some of the cheapest new cars you can buy.
Then you have little fragments of that rubber belt that come off. They led to blockage of the oil pickup pipe resulting in oil starvation. Usually old belts are hard and have lost their elasticity, but this one is all flaky. In worse cases, the belt snaps and destroys the whole engine. Some have reported this happening as low as 50,000 miles even with regular oil changes.
I Do Cars found major issues while tearing down the 1.0-liter EcoBoost. Removing the timing cover reveals that the teeth on one of the belts are completely worn down. This belt is supposed to move the oil pump and a balancing shaft which the 3-cylinder obviously needs. The larger belt which controls the timing is also in horrible shape, cracked and brittle.
Before it gave out, the 3-cylinder probably ran very rough without the balancing shaft, and without teeth on the belt, the oil pump wasn’t working well, so it starved the bearings and crankshafts of oil. We’d call that premature engine failure, considering the car was only a few years old, and that’s why the 1.0-lier EcoBoost could be the worst small modern engine.