“Work hard, play hard” is a mantra of many. Have you ever considered that hybrids follow that same creed? With several technologies at play, there’s a lot that can go wrong. But thanks to masterful engineering, motors, batteries, water, and oil can be playground buddies who get along just enough to produce a fuel economy benefit.
We know that hybrids are more fuel efficient than conventional ol’ gas engines, but obtaining those extra mpgs is complicated. A standard hybrid involves packaging an electric motor and battery within the powertrain to capture would-be wasted energy and storing it for later use through regenerative braking or even adding power to the gas engine. This energy catch-and-release leads to better fuel economy, 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 of Engineering Explained points out, “Hybrid vehicles are a great solution to improving fuel economy, but they have their own unique challenges.”
Fenske notes that “[b]ecause hybrid engines start and stop frequently, this often results in lower engine temperatures, which in turn can create issues with water and fuel dilution. Frequent start/stops, water, and fuel can all create problems that exacerbate engine wear.”
This doesn’t mean hybrid engines are unreliable. They’re just built different.
An engine stop-start can happen during a variety of scenarios, including deceleration, traveling downhill, or when the vehicle idles at a stop light, something most drivers are used to by now with newer cars. Using the engine in these low-energy situations can be overkill, so the electric motor will activate instead. It’s a tag team of brawn and brains.
Stop-start, however, is rough on engines because of the frequency. Motor oil brand Mobil1 says 80 to 90 percent of engine wear occurs from engine start-up. When you consider how many traffic lights and all-way stop signs are littered throughout cities and suburbs, that’s quite a bit of on-off stop-and-go. Yowza.
The good news is that cold starts, which need as much as 15 seconds for the engine oil to circulate and properly lubricate components, happen less often. The roughest cold start will be after a vehicle has been sitting for an extended period, like overnight. The engine is cold, the oil is cold, the air is probably cold, just everything is cold.
You move slowly when you’re chilly, but once you’ve warmed up after a hot coffee or shower, you stop dragging your feet. And engines? They’re just like us! So, while cold starts will be harsh, stop-starts during the day aren’t a big deal.
Another concern is water, which is an inevitable byproduct of combustion. Because hybrid engines aren’t consistently running like ICEs, oil temperatures will remain low on average. The low temps mean more moisture can build up rather than dissipate. Sounds like a lie, but water isn’t a great lubricant, especially for an engine, and standing water can lead to corrosion.
How to minimize water-related wear? Depending on where you live or your driving habits, a hybrid engine might not get hot enough to burn off that moisture. Regularly scheduled maintenance and using the motor oil formulated for your vehicle are basically all you need to keep this in check.
Reliability is the last thing you have to worry about when it comes to the most popular hybrids. From Toyota leading the way in hybrid tech and product reliability to Ford Escape hybrids with more than 400,000 miles operating as New York taxis, there are plenty of high-mileage examples of how things that don’t normally mix (i.e., oil and water) can play well together after all.
