Spoiler alert: engines require maintenance to stay healthy
The latest video from Engineering Explained covers the 10 main reasons why engines lose power over time. None of this will come as a surprise to anyone who tinkers with cars, but it does make for a nifty maintenance compilation to follow because it basically goes step-by-step from easy fixes, to stuff that generally requires an engine rebuild. For those car buffs who aren’t as mechanically inclined, this breakdown can help explain the fundamentals so you’re better prepared the next time you head to the shop for some work.
The 10 reasons are broken down into four main sections that cover the basics of engine operation: air, fuel, compression, and spark. As you might expect, air can often be the easiest fix for a loss of horsepower, as evidenced by the massively clogged air filter the video showcases. Plugged exhaust systems are also mentioned, but the video also touches on stretched throttle cables, which is a lesser-known but surprisingly common problem on older vehicles.
Moving on to fuel, the video mentions dirty fuel injectors and worn out fuel pumps – items that aren’t quite as easy to replace as air filters, but still relatively accessible on most cars. Another solid mention in the video is the tendency for fuel pumps to get weaker under high demand (high engine rpm) while still be strong a lower fuel flow rates. This can be a tough problem to detect and is easily overlooked when trying to track down engine problems.
The last two categories are where things get more indepth, and as Indiana Jones once said, it’s not the years but the mileage. Piston rings can wear, causing a loss of compression in the engine. Deposits can also form on the valvetrain and cylinder walls, leading to additional compression loss. There are various fuel additives that can help with deposits, but in severe cases the engine simply needs to be torn apart. The last easy fix mentioned is spark plugs, which can get fouled or worn to the point where the gap is simply too large for a good spark, causing misfires.
In other words, a well-maintained engine will hold its horsepower longer. Take care of it, and it will take care of you.