Under the Hood

The Under the Hood Channel explores the systems that make your car function correctly. Learn about car parts and systems and how to do routine maintenance.


I notice that there are certain cars whose headlights seem to have a blue-ish or green-ish tint. A lot of times these headlights are on expensive cars. Are these headlights different from normal headlights?

So why does a diesel engine with huge torque and low maximum RPM get a low horsepower rating compared to a low torque, high revving race car engine? Find out why in this article.

The goal of a carburetor is to mix just the right amount of gasoline with air so that the engine runs properly. Learn more about how a carburetor in a gasoline engine works.

There are three different engine configurations commonly used in automobiles -- inline, V, and flat. Learn the difference and find out what designers look at when deciding which configuration to use in a car.

It's the reason you can put the pedal to the metal and go from zero to 60 in seconds. But to the uninitiated, an engine can look like a jumble of metal and wires.

What does the computer in a car do? What was the Y2K scare about our cars starting?

Forced induction systems are one of the best ways to make lots of power, so which system is better? Turbochargers or Superchargers? Learn the pros and cons of both.

Mazda has been using this type of engine in some of its cars for several years. Learn what a Miller-Cycle engine is and how it works.

If you're planning to make more power from your engine. Switching to hi-performance exhaust headers are a good idea. Find out how exhaust headers work to improve engine performance.

Glare-resistant rearview mirrors can be useful when the vehicle behind you has extra bright headlights. Find out how simply flipping the rearview mirror can block out the bright light.

What is the difference between a normal lead-acid car battery and a "deep cycle" battery? I have a trolling motor on my boat and I don't see why I can't use my car's battery with it rather than spending another $80 on a deep cycle battery.

Japanese automaker Honda is best known for their VTEC system. Almost all of their newer vehicles are equipped with VTEC engines. But what does it actually do and how does it maximize engine performance?

How does the thermostat in a car's cooling system work? I had to test my thermostat today and was amazed as I watched it!

An oxygen sensor in a car is a very important part of making your engine run smoothly. Learn what it does and what can happen if your oxygen sensor fails.

I'm always hearing people talk about pumping nitrous oxide into an engine. How does nitrous oxide help an engine perform better?

I see many dump trucks with wheels on two rear axles on the ground and a third axle with elevated wheels that can be lowered. These seem to be used when the truck is full -- but why include what must be expensive hardware to raise and lower the wheels? Why not just keep them down at all times?

I would really like to know how people can make their cars jump up and down with their front wheels like they do in movies like "Boyz in the Hood."

The battery light on my car dashboard comes on whenever I am driving. How serious is this? The car seems to be working fine...

If you have a vehicle that needs to be tested for emissions, you might want to check on the condition of your catalytic converter. So what is it and what does it do?

Take diesel-engine technology, throw in a two-stroke cycle, and you've got the basis for the huge engines found in trains and big ships. Learn about the diesel two-stroke engine!

Ever wonder what the difference is between a gasoline engine and a diesel engine? Diesels are more efficient and cheaper to run than gasoline engines. Learn what makes diesel engines different!

Gear ratios are what allow a car to reach a high rate of speed or climb a steep hill. Learn about gear ratios, gear trains and planetary gear systems.

Surprisingly enough, horsepower actually does refer to the power of horses. But over the years it’s become a valuable measurement for all kinds of machinery. Learn how horsepower is calculated and what it means to the automobile industry.

If you have a car chances are you also have a tire-pressure gauge. Learn how this pen-sized device measures air pressure and why the little stick inside doesn't just fly right out the back!

What does that funny "H" pattern on my car's gear shift have to do with my transmission? How does it make the car change gears? And when I mess up and hear that horrible grinding sound, what is actually grinding?