This explainer video shows why hybrid vehicles are so much harder on engines

“Work hard, play hard” is a mantra of many. Have you ever thought about hybrids following the same creed? Because multiple technologies are used, a lot can go wrong. But thanks to masterful engineering, engines, batteries, water and oil can be playmates that get along just enough to provide a fuel economy advantage.

We know that hybrid vehicles are more fuel efficient than traditional gasoline engines, but achieving those extra mpg is complicated. A standard hybrid integrates an electric motor and battery into the powertrain to capture potentially wasted energy and store it for later use through regenerative braking or even providing power to the gas engine. This capture and release of energy results in lower fuel consumption, quieter vehicle operation and better resale value.

But hybrid engines have to work hard, very hard, to maintain that unique balance of electrification and efficiency. As Jason Fenske from Technology explained emphasizes: “Hybrid vehicles are a great solution for improving fuel economy, but they have their own challenges.”

Fenske states that “[b]Because hybrid engines start and stop frequently, this often results in lower engine temperatures, which in turn can lead to water and fuel dilution problems. Frequent starting/stops, water and fuel can cause problems that increase engine wear.”

That doesn’t mean hybrid engines are unreliable. They are simply built differently.

Engine stop-start can occur in various situations, including when decelerating, driving downhill, or when the vehicle is idling at a traffic light, which most consumers are familiar with. The use of the motor may be excessive in these low energy situations, causing the electric motor to activate instead. It’s a tag team full of strength and brains.

However, due to the frequency, the start-stop function is difficult for engines. According to motor oil brand Mobil1, 80 to 90 percent of engine wear occurs when the engine is started. Considering how many traffic lights and continuous stop signs are scattered throughout cities and suburbs, that’s a fair amount of stop-and-go driving. Yowza.

The good news is that cold starts, where it takes up to 15 seconds for the engine oil to circulate and components to be properly lubricated, are less common. The most difficult cold start occurs when the vehicle has been sitting for a long period of time, such as overnight. The engine is cold, the oil is cold, the air is probably cold, everything is cold.

If you’re cold, move slowly, but once you’re warmed up after a hot coffee or shower, stop dragging your feet. And engines? They are just like us! So while cold starts will be tough, stop starts during the day are no big deal.

Another problem is water, which is an inevitable byproduct of combustion. Since hybrid engines do not run constantly like internal combustion engines, oil temperatures remain low on average. Due to the low temperatures, more moisture can accumulate than evaporate. Sounds like a lie, but water is not a good lubricant, especially for an engine, and standing water can lead to corrosion.

How can water-related wear and tear be minimized? Depending on where you live or your driving habits, a hybrid engine may not get hot enough to burn off the moisture. Regular maintenance and using the appropriate engine oil for your vehicle are basically enough to keep this under control.

Reliability is the last thing you need to worry about with a hybrid engine. From Toyota leading the way in hybrid technology and product reliability to Ford Escape hybrids with more than 400,000 miles on the clock as New York taxis, there are many high-mileage examples of how things that don’t normally go together (e.g. Oil and water) can work well together.