What The Colored Markings Under Your New Car's Hood Actually Mean

Driving your brand new car can sometimes come with a learning curve. You're adjusting to the feel of your new vehicle, mastering what the different noises and alerts mean, and perhaps even getting used to new safety features like automatic emergency braking or blind spot monitoring. Many of us may never even raise the hood to check out the gleaming engine, but if you do, you may notice a series of odd, brightly-colored marks in different areas of the engine compartment. It could look like a child went wild with sidewalk chalk, but these marks actually belong, and they have a story to tell.

These kinds of factory markings are not limited to the automotive industry. When you purchase fine jewelry, you look for a mark that indicates it is sterling silver or even 18-karat gold. Our food, like eggs and meat, often bear indicators that verify quality, and our electrical components are marked to indicate safety. 

The same holds true for those colorful lines and dashes under the hood of your car: They are factory markings that indicate quality control and safety assurances. Because they illustrate that your new car was assembled well, you may even want to look for these marks before you buy or even rent a car. Here's how to decipher what those marks and colors specifically mean.

Buyers may find several different types of marks underneath the hood of their car. Witness marks are usually basic lines that mark both a bolt and the place where it's tightened. If the line remains unbroken, all is well. If the mark no longer lines up or is fractured, however, it indicates that the bolt is loose. The other type of common marks are called torque seals. This paste, which is typically applied to essential parts, dries after application and will crack with movement. It's another visual indicator for professionals that something has gone wrong, providing a clue as to where the problem may lie.

If you open your hood and take a look, some of the marks may be blue and yellow, but you could also spot other colors. The colors themselves actually don't mean anything at all — at least, there's no universal standard used by automakers. They tend to use colors that will stand out in order to make these marks and seals visible. Each brand might have their own system, but it differs by manufacturer.

For many of us, these pops of color hiding under the hood don't mean much, but you may want to look for them when you purchase or rent a car, as they are a visible indicator of how well the vehicle was taken care of when it was assembled. If you're savvy enough to perform some DIY maintenance on your own car, take care to learn what you're doing and use the right tools, like a calibrated torque wrench, to ensure that everything remains aligned with the manufacturer's specs.