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.

Topics to Explore

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How do I know if my catalytic converter has failed?

Exhaust emissions test check for the absence of a catalytic converter or a malfunctioning one during an emissions inspection. Read on to learn how you can find out if your catalytic converter has failed.

How Tires Work

Are you in the market for a new set of tires? Is all that confusing jargon the tire sales clerks or "experts" are using making your head feel like a tire spinning out of control? Find out all about car tires.

How Differentials Work

Car wheels spin at different speeds, especially when turning. The differential is what lets a car make turns with ease. Find out how this key component allows the wheels to rotate at different speeds.

How do stabilizer bars work?

Stabilizer bars are sometimes also called anti-sway bars or anti-roll bars. Find out how stabilizer bars keep a car's body from "rolling" in sharp turns.

Is it true that a diesel engine can operate under water while a gasoline engine cannot?

Diesel powered Humvees are capable of running in "extreme" conditions, and these conditions can include deep submersion during river fording. Is it only possible to go underwater with a diesel powered vehicle?

If diesel engines are more efficient why do most cars have gasoline engines?

I have read the articles on diesel and gasoline engines. Several of my friends drive Mercedes turbodiesels and I have seen several diesel hummers. I was wondering that if diesel engines are more efficient and use cheaper fuel why don't all cars use diesel?

What's the best way to increase horsepower?

There are many different ways to create more horsepower from a stock engine. Learn about the different ways to make your engine more powerful.

Will we ever have space ships parked in our garages?

Will we ever have spaceships parked in our garages so that we can fly to the moon whenever we feel like it?

How do the blue-ish headlights on expensive luxury cars work?

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?

Why do big diesel engines and race car engines have such different horsepower ratings?

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.

How does a carburetor work?

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.

Is there a difference between inline and V engine configurations?

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.

How Car Engines Work

It's the reason you can put the pedal to the metal and go from 0 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 does the computer in a car do? What was the Y2K scare about our cars starting?

What is the difference between a turbocharger and a supercharger on a car engine?

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.

How does a Miller-cycle engine work?

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.

How do exhaust headers work to improve engine performance?

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.

How does a car's rearview mirror work when it's in the glare-resistant setting?

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?

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.

What does the VTEC system in a Honda engine do?

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?

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!

How does the oxygen sensor in a car work?

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.

How does nitrous oxide help an engine perform better?

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

Why do some dump trucks have extra moveable axles?

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?

How do they create the hopping cars you see in the movies?

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."