Does A Cars Odometer Reset With New Engine? (Don’t do it!)


Love that new engine smell, prrrr. No more tow trucks, no more calls to work – I’m running late, no more borrowed cars… it’s all giggles now. But it does make you question if the mileage read out should reflect that as good as new car feel.

Does a cars odometer reset with a new engine? A cars odometer does not reset with a new engine. The odometer is a record of all the components of a car, not just the engine.

In this post you’ll learn why resetting an odometer with a replacement engine is an inaccurate and misleading reflection of the cars history.

Odometer For All Components

Dash clock

It’s understandable to want to reset the odometer with a new engine, the growling is gone, been replaced with a sweet sounding purr.

Changing the mileage read out however, wouldn’t reflect the true story. Your car is made up of hundreds of components and the mileage record is a record of their life too.

Sure, you could argue that the engine is the main and most expensive component. But there’s only so many miles in any component and as a purchaser wouldn’t you wan’t to know the true mileage on other expensive parts of a car.

Components like:

  • Transmissions
  • Differentials
  • Brakes
  • Steerings
  • Suspension

Many components are mechanical with electronic assistance requiring routine maintenance set intervals. Inaccurate mileage reading could cause these components to miss out on some critical mileage sensitive maintenance.

Component damage or failure is a real risk. Maintenance such as transmission oil & filter change, Brake fluid change and flush, differential oil change, power steering fluid change,

Illegal To Wind Clock Back

Besides it been plain wrong, it’s illegal to tamper with the mileage reading of a motor car. Doing so with the intention to deceive a buyer could land you in trouble with the police.

Modern Clocks

Dash lights

Modern car dash clocks are digital and that’s makes them easy to manipulate. You won’t need to look to far in the classifieds to find a vendor offering Mileage correction services.

It is of course totally dishonest and not at all cool. What most of these guys don’t know is that their deception can be traced. Many cars keep more than one record of miles travelled, although the dash clock may have been manipulated, the PCM and TCM may also have a record and their records aren’t as easily manipulated.

In addition, a full record of a car, including its mileage is stored at main dealers when ever they are brought in for service. This type info is pretty easy to check, cloud computing has made all this info available to all network dealers.

Service History

Service history

The service history of a car is important, it effects the value big-time, no service history and most buyers will assume the worst.

Turning the mileage back will be at odds with the service records of the car and so will cause either suspicion or confusion neither are good.

I’ve bought a ton of cars over the years and assuming a seller was straight with me and told me the clock was turned back, I wouldn’t buy the car. It’s unusual activity and creates a cloud of doubt. It will negatively effect the resale price.

Related Questions

Do dealerships do engine swaps? Most dealerships will do an engine swap so long as the replacement engine is identical to the old unit. Fabricating brackets, modifying firewalls, manufacturing bespoke components like exhaust systems etc are not dealerships workshops strengths and it’s not likely they’d undertake such work.

John Cunningham

John Cunningham is an Automotive Technician and writer on Rustyautos.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write articles that help fellow gear-heads with all aspects of classic car ownership, from tires to roof aerials and everything in between.

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