Here’s another simple check that can yield a big result. Engine oil is the lifeblood of your engine. If it’s low, your engine isn’t feeling very well, and as a result, it’s less efficient. A loss of efficiency equates to a decrease in fuel economy. I know your engine doesn’t really have “feelings,” but you get the point. The harder your engine has to work, the more fuel it will use. It really is that simple. Checking the engine oil is a great check if you are having issues with poor fuel economy. If you find that it’s low, top it off to the proper level and recheck your MPG.
Another thing to consider is changing your oil. Fresh oil lubricates better than old oil. As a result, your engine won’t have to work as hard to do its job. So if you’re in doubt as to when your oil was last changed, you might consider changing it if you’re having issues with poor fuel economy.
Something else to consider is using synthetic oil. Synthetic oil has better flow characteristics and lubrication ability than conventional oil, and as a result, your engine will run with less resistance when using synthetic oil. A word of caution on synthetic oil though. If your engine is old and leaking, you might forgo synthetic oil. If you switch to synthetic on an older, worn-out engine, you might see a negative result. Synthetic oil is very good at what it does, but it can’t repair a worn-out engine. In fact, it can make a worn-out engine worse. If you have an older engine, when switching to synthetic oil you might see more leaks and perhaps even have more engine noise than you did with conventional oil. However, if your engine is in good shape and doesn’t leak, you might consider switching to synthetic for better fuel economy. I often get asked if you can switch back and forth between synthetic and conventional oil. The answer to that question is, yes you can. Synthetic oil is designed to mix with regular oil, in fact many synthetic oils are really blends of synthetic and conventional oil. There are actually few fully synthetic oils. So if it’s already mixed in the bottle, you shouldn’t have any issues switching from synthetic to regular oil should you so choose.