What Uses Less Gas – Coasting Or Engine Braking?
Chances are, at some point in your driving education, whether it be on the back roads with your dad or in Driver’s Ed in high school, you were told one of these options was better when it comes to either costing down hills or keeping the transmission in gear and letting the engine keep the cars speed in check while gravity does it’s work. I was personally told to leave the transmission in gear because pulling the car in and out of drive over the life of the vehicle would add unnecessary wear and tear to the trans, and that certainly makes sense if you’ve ever looked at all the goings on inside and automatic transmission. I was also told, and have no actual proof of the validity of this, that if you leave the trans in gear and let the engine brake for you, it can “stretch” the rods in the engine. This wasn’t meant to be literal, as the rods certainly aren’t going to stretch, but was meant instead to imply it would add unnecessary strain on the bearings that would elongate them, leading to premature failure.
Jason from Engineering Explained, one of our favorite automotive education-based YouTube channels, has done what he does best and tackled the question head on, taking to the road himself to test out both theories. Jason approached the situation strictly from a fuel-efficiency standpoint, recording what the car’s on-board electronics show for fuel consumption numbers and he strolled up and down the meandering hills.
We aren’t going to spoil the results, you’ll have to watch the video and see for yourself which is better. After you watch, head back over to Facebook where you found this post and let us know which approach you have always taken, and let us know if this video has changed the way you approach downhill coasting in your car?