How To Tell If a Vehicle's Odometer Has Been Tampered With?

Factual Questions
1

So I’m considering buying a used car, a 2000 Chevy Impala with 43,000 miles on it.
I was immediatly suspicious because that’s a very low mileage for the year.

I know there’s some mechanical dopers on here and was looking for some pointers.

What specifically should I look for as a sign to rule out any tampering?

Thanks
Gus

2

Get a Carfax report on it.

3

You can check with CARFAX

I also caught one of these once, when I noticed that the font of the numbers on the odometer didn’t match the font on the trip odometer.

4

I guess I shouldn’t have taken the time to type out that second sentence. That was fast Q.E.D..

5

I wouldn’t be too suspicious unless the seller seemed sketchy or was a teenager or something.

When I bought a Crown Victoria from my Grandpa in 2004, it was a 1996 model with just under 20,000 miles on it. Some people just don’t drive much.

What I would look at is under the hood. A car just sitting around can be almost as bad as driving it regularly. Check for dry rot on hoses and belts, they may all have to be replaced.

Check the tires too.

6

In old-style odometers, a tell tale sign that it has been tampered with is when the numbers do not line up properly

Now the majority of cars have odos with digital displays. Some of them can be hacked but if this is not possible they can swap the whole instrument cluster with another one that has a smaller mileage number.

On modern cars the real mileage is also stored in the ECU and can be viewed (along with other useful info) when connected to the diagnostic. This is a lot harder to tamper with but again, if the ECU is swapped the mileage will be different.

7

You can also get a pretty good idea of whose been driving the car by checking the presets on the radio.

8

Is the odometer digital? If so the mileage is generally contained within the body control module and other than replacing it, is not subject to tampering.

It is possible to obtain a bcm from a wrecking yard thus altering the mileage but do to the cost of the part, either from a wrecking yard or a dealer is prohibitive.

9

Thanks everyone,

I should’ve mentioned I’m in Canada, and I didn’t see that us Canadians qualify for Carfax service.
Anyone know?

Thanks
Gus

10

The corresponding Canadian service is called Carproof.

Generally, if you have a good idea of the wear items, you can determine if the miles are true or not. Check for wear on the floormats, pedals, radio controls, seats, stuff like that which would tend to get worn out with a lot of miles. A car with a lot of miles will look like a car with a lot of miles. You can go look at a few legitimately high mileage Impalas if you want, to get an idea. They are pretty common cars.

11

That generation of Impala with the 3.4l V6 was fairly notorious for a problem with Dex-cool corroding the intake manifold gasket. See this class action lawsuit:

You should inspect the engine oil for signs of coolant, which would show up as a milky white residue on the oil cap. If it’s OK, you should flush the coolant and use something other than Dexcool, and/or also preemptively replace the intake manifold gasket.

12

That seems pretty normal mileage if it is from someone who doesn’t drive much. My grandparent’s have a 2000 Dodge with just over 45,000 miles on it, and the past 7.000 is from my brother driving it this past year.
Also, check the steering wheel. Usually after 50,000 to 70,000 they start to look and feel worn out. Cars with less mileage still have a “new” feeling steering wheel. (I’m talking cosmetically, not in the way they drive, but that can happen too)

13

You learn to see how much wear you would expect on a 20,000 mile vs 50,000 vs 100,000 mile car. Course they could have changed out the pedals too.

14

Ask how it’s been used. If the seller’s workplace is 2 miles away then there’s no real commute and a low mileage is to be expected.

15

The number may well be legit - and as FoieGrasIsEvil warned, be cautious if so. A life of infrequent, short trips (where the engine rarely reaches full temperature) is quite hard on the car.

All miles are not created equal: This car’s engine may be much farther along in its life cycle than an interpretation calibrated for more typical use would suggest.