How To Read An Odometer

An odometer is a tool of measurement used to determine how far a vehicle has traveled. It works by use of a small gear driven wheel that runs off of the output shaft of the transmission. The number of rotations of that shaft is the same as the number of rotations of the wheels. Since the output shaft spins the same as the wheels, and accuracy of the measurement won't suffer, they put the gear driven wheel in the transmission. They do this because it is less likely that the small wheel will break inside the transmission than near the road and wheels where rocks may crack or break the wheel.

The distance traveled is calculated by multiplying the diameter of the tire by pi (3.14159) to find the circumference of the tire.  The circumference is then multiplied by the number of rotations of the output shaft which is the same as the number of rotations of the tires!

That math for the odometer is done in the lab where the vehicle is being designed. The vehicle doesn't actually do this math. The small gear driven wheel is designed to be the correct diameter in relation to the diameter of the output shaft so that it doesn't need any calculation, but simply to count.

The older mechanical style odometers, like the one pictured above, use numbered wheels with 0-9 on each of the wheels. The numbers count up from right to left. The far most right wheel will count from 0 to 1 to 2... on up to 9 and then when it goes back around to 0 the wheel to the left of it will turn from 0 to 1.  When the first wheel gets to 0 again, then wheel to the left will turn to 2. That pattern is followed all the way out to all the digits.

The furthest wheel to the right is the 1/10 wheel. It tells you how many tenths of one mile you have gone. If there is a 1/10 wheel it is colored white or a different color from the rest, or it is highlighted, or it follows a decimal point on the newer digital odometers. If that wheel looks identical to the rest of the wheels then there is no 1/10 wheel and it is just the ones place.

The places go from right to left like this: tenths place, ones place, tens place, hundreds place, thousands place, ten-thousands place, and on newer vehicles hundred-thousands place.

Older vehicles had no use for a hundred-thousands place in the odometer because the vehicles weren't expected to last that long without major work. This was do to many things including looser machining tolerances in parts like the valve and cylinder bores and throughout the whole engine, lesser quality lubricants, and that materials engineers had not discovered all the great materials used in modern vehicles.

Today's vehicles use digital odometers. They work just the same as the analog odometers, but use a neat little screen instead of the numbered wheels. They have the 1/10 place after a decimal instead of using a differently colored wheel.

Most vehicles also have what is called a trip odometer, or simply a trip meter. It can be reset back to zero at any time the driver chooses, whereas the odometer is not able to be reset by the driver. The trip odometer allows the driver to measure their current trip, which is handy for calculating gas mileage. I've used my trip meter for two things. I reset my trip meter after I fill up my gas tank all the way full, then when I fill up again I take the number the trip meter gives me and divide it by the amount of gas I was able to put in my gas tank. So I've taken my miles driven and divided by gallons used to get my recent MPG or Miles Per Gallon. The other use is for vehicles where the gas gauge no longer works or is inaccurate. Fill up a gas can with spare gasoline. Fill your vehicles gas tank to full. Reset the trip meter. Drive your vehicle until you completely run out of gas and the engine dies (do this in a place that would be safe to do so like a road out of town or small neighborhoods, not on main streets or in busy traffic). Look at your trip meter and take note of the number of miles you were able to get out of a tank of gasoline. That number is now E for Empty just like on your gas gauge. You can put the spare gas in the tank now so you can get to a gas fill up station. Now every time you get gas fill your tank all the way, and reset your trip meter. Plan to fill up about 100 miles before that Empty number so that you are safe, because if you are idling somewhere for an extended period of time, that is using gas and it is not being reflected in trip odometer reading. Two of my personal vehicles have had the gas gauge not work and I have used this method for the entire time I drove them, and have never run out of gas.

When an old style mechanical odometer would reach 99,999.9 miles, all of the numbered wheels would then "turn over" to zero. It would then read 00,000.0 as if the vehicle were brand new and had never been driven, despite the fact that it had been driven 100,000 miles! This could even happen several times and then would be referred to as having rolled over twice or three times or whatever had been the case. It was relatively common for older vehicles to have their odometers roll over. Newer vehicles that have hundred-thousands places do not roll over. A very long life of a vehicle would be 400,000 miles. Most won't make it that long, some may even make it longer, but to roll over these odometers a vehicle would have to have driven ONE MILLION miles, which is unheard of. It is a different case for semi trucks. They make it to ridiculously high mileage! I'm only talking about passenger cars and light trucks.

People in the know, that have mechanical skills, can sometimes change the odometer readings of vehicles. Changing an odometer with the intent of fooling a buyer is called "clocking" or "odometer tampering" and is VERY illegal. People still do it, though, because it is very lucrative. A person could buy a high mileage vehicle that looks nice for cheap, and roll back the odometer to something low, like 40,000 miles or less and sell it for a huge profit. I'll be writing a post about clocking soon, but for now I just wanted to make you aware of it.

I hope this helped you learn about how to read an odometer and a little about how they work. If you have any questions, please leave it in the comments below!

Oil Capacity Chart in PDF

Here is a PDF file that contains all of the charts I've uploaded(General Motors, 2014 GMC Sierra and Chevrolet Silverado, Chrysler, and Ford).  I am especially proud of this post because I didn't know how to display a PDF in a blog post.  I did about a half an hour of research to learn how to do this.  I'm very excited about it!

This is so that you can print off the whole thing and tape it to your toolbox, cupboard, shelving unit, or wall in your shop or garage.  With this thing you can become the most popular guy in your neighborhood.  You'll be able to do everyone's oil changes because you'll have this information right there.

To download this .pdf so you can print it (or have it handy on your computer) just run your mouse cursor over the preview and in the top right hand corner a button that says "Pop-out" will appear, click that button.  On the page that brings you to you can select download from the buttons at the top.

Enjoy wrenching and making new friends!

P.S.  If you ever want to embed a preview of a PDF or any other kind of document on your blog or website then you'll be interested in what I found in my research.  This was the post that helped me most.

How Much Oil Does My 2014 GMC Sierra or Chevy Silverado Take?

If you have a new GMC Sierra or Chevrolet Silverado, that's 2014 or 2015, then this is the oil capacity chart you are looking for.  The 5.3 Liter engine and 6.2 Liter engine have gone from 6 quarts to 8.5 quarts.  Also, the 4.3 Liter engine has gone from 4.5 quarts to 6 quarts.  These engines also have a requirement of only DEXOS1 or higher quality oil.

Let this chart help you up-keep your boss new truck!

Check out my other oil capacity charts

2014 GMC Sierra/Chevrolet Silverado

Engine Size Quarts of Oil Oil Type

4.3L V6 6 5W30 DEXOS1

5.3L V8 8.5 0W20 DEXOS1

6.0L V8 6 5W30 DEXOS1

6.2L V8 8.5 0W20 DEXOS1

How Much Oil Does My Ford Take?

When you're getting ready to do an oil change on your car or truck, you're going to need to know how much oil to use.  That's exactly why I made this handy-dandy look-up chart for your Ford!  Just so you know, Ford also makes Mercury and Lincoln.

I collected this information one vehicle at a time.  Each time I did an oil change and I didn't already have the engine listed, I'd look it up and record it so I'd save time the next time.  This table took the longest to collect the information for because I've always worked at Chevrolet dealerships and Fords just didn't seem to come through as often as other makes.  Anyways, I'll quit my rambling.  Have fun with your oil change!

Also check out the rest of my oil change charts


Engine Size Quarts of Oil

1.6 4.3

2 4.5

2.3 4.5

2.5 5.3

3.0 V6 4.5


3.5 5.5

3.7 5.5

3.9 5

4 5

4.2 6

4.6 6

5 7.7

5.4 7

6.8 7

How Much Oil Does My Chrysler Product Take?

This is the second in my series of posts providing charts that tell you how much engine oil your vehicle takes when performing an oil change.  Chrysler covers Dodge, Plymouth, and Chrysler (obviously).  This chart will be handy if you drive a MOPAR.  Use it well, it's very powerful! :)

Don't forget to check out the other charts in my series


Engine Size Quarts of Oil

2 4.5

2.3 5

2.4 4.5

2.5 4.5

2.7 5.5

3.3 5

3.5 5.5

3.6 6

3.7 5

3.8 5

3.9 4

4 6

4.7 6

5.2 5

5.7 6.5

5.9 5

8 7

How Much Oil Does My General Motors Vehicle Take?

When preparing to perform an oil change it is always important to make sure you have everything you need, and that includes the proper amount of oil.  I made these charts for quick reference when I was doing oil changes.  This particular table is just for General Motors vehicles.  These engines are in cars, trucks, and vans made by GMC, Chevrolet, Pontiac, Oldsmobile, Buick, and Cadillac.  I hope you find them handy!

Also check out my other oil capacity charts

General Motors

Engine Size Quarts of Oil

EcoTec 5

EcoTec2 3.9

1.8 VVTI 4.4

1.9 4

2.0TD 4.5

2.0T 6.3

2.4 4.5

2.5 5

2.8 5

2.9 5

3.0 VVTI 6

3 6

3.1 4.5

3.4 4.5

3.5 4

3.6 5.5

3.7 6

3.8 4.5

3.9 4

4.2 7

4.3 4.5

4.6 7.5

4.8 6

5.3 6

5.7 5

6 6

6.2 6

6.6 10

8.1 7

How Much Oil Does My Car Take?

     In this, my first blog post, I want to do a little foreshadowing. I want to let you know some of what I've got planned for this blog. Hopefully it will be a large blog with lots and lots of posts. I want it to be a regularly updated source for information related to basic maintenance that can be performed by vehicle owners.
     My first few blog posts will be about how much oil to put in your car's engine. I am going to use tables to show how much engine oil is needed for each size of engine. I am going to break the tables up by vehicle make (General Motors, Chrysler, Ford). I might even post them all together in one document.  I am not going to post any information about foreign cars and their engine oil capacities, I will only have domestics (at this time).
     I think this information will be found useful by anyone attempting to perform their own oil changes. I have done oil changes professionally for 5 years, and I have completed THOUSANDS of oil changes. I have made these charts, adding small bits at a time. Every time I would change the oil in a vehicle and have to look up the oil capacity, I would record those numbers. Over time I have accumulated these very helpful charts.
     It is a serious pain-in-the-butt to have to look up the engine oil quantity or capacity every time you do an oil change because it can be quite difficult to find this stuff. With the Internet being so big, and so many experts in the world uploading stuff to it, you would think there is all the information known to man on it, but that's not always true. Some of the information is available online for free, but not all of it. You can get this information about every year, make, and model of vehicle, and get access all online, but you have to purchase a subscription to services like ALLDATA or Mitchell 1's OnDemand5 or ProDemand. These services are GREAT and give you all the repair instructions and specifications for all repairs and replacements on the vehicles they cover, but it is overkill if you aren't a career mechanic. Another option is to purchase a repair manual. It is the same information as was covered in the online services, but is more in depth. The repair manuals are real life books that are made for one specific make and model, and may cover a range of years or only one specific year. They are perfect for someone who owns a car and plans to do tons of work to it, but again it is really too much for a person wanting to do basic maintenance on their vehicle. You can also check the glove box for the owner's manual, which would have the engine oil capacity, along with other fluid capacities. If you are the second or third or later owner of the vehicle this manual may be missing, and they are no help unless they are there.
     One of the big reasons for doing your own oil changes at home is to save money. If you spend money on any of this information, then you'll have to do that many more oil changes before you actually START SAVING MONEY. By posting these charts I hope to save you that money!
     There will be a lot more coming in the way of topics and blog posts, but for now this is what I've got flowing. Be sure to comment about any questions or topics you'd like to hear more about. I'll try my best to get back to everyone!
     Thanks SO much for READING MY FIRST BLOG POST!!!

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