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Vin Codes

By Mark Sabourin

Starting in 1977 Congress mandated that all automobiles (including foreign cars) sold in the U.S. must have a Vehicle Identification Number (the VIN) be affixed to the vehicle.

For our 1979 - 1980 cars we have a 13 digit/letter code VIN.

In 1981 the VIN was expanded to a 17 digit/letter combination and included information that would give special purpose (i.e. Law Enforcement) interests the ability to find out if the VIN was correct for the vehicle in question, to prevent theft of cars, VIN falsification and more. A fairly complicated formula is required to decode the 17 charactor VIN to get tthe new "Check Digit" but it is available to the public.

Reading every placement digit or character of the VIN isn't confusing. But the two forms are somewhat different. I'll explain them both as they apply to our cars

Year Codes

1979 1980 1981 1982 1983 1984 1985
9 A B C D E F

1979 & 1980 13 Digit-Charactor VIN's

Example: 1980 Riviera with a 350ci "R" Gas engine 2Dr. Coupe VIN 4Z57RAE420046

Place Example Code Meaning Other Values / Notes
1 4 Division: "4"= Buick; "6"= Cadillac; "3"= Oldsmobile
2 Z Model: "Z" = Riviera; "L" = Eldorado
3 & 4 57 Body Style: what TYPE of car it is 57= Coupe
5 R Engine Code See Below
6 A Year Code (See above)
7 E Assembly plant Linden, NJ for our cars= "E"
8 to 13 420046 Production (sequence) Number Preceded by the Division Code

Engine Codes for 1979 - 1980

  • 3- 231ci V6 Turbo
  • Y- 307ci V8 Carb
  • R- 350ci V8 Carb
  • B- 350ci V8 EFI 1979 Cadillac
  • 8- 350ci V8 EFI 1980 Cadillac
  • N- 350 Diesel
  • 9- 368ci V8 DEFI 1980 Cadilac

1981 to 1985 17 Digit-Charactor VIN's

Example: 1982 Riviera with a 307ci "Y" engine 2Dr. Coupe VIN 1G4AZ57Y3CE401547

Place Example Code Meaning Other Values / Notes
1 1 Country of Manufacture. "1"= USA
2 G Manufacturer/Make G = All General Motors vehicles
3 4 Division "4"= Buick; "6"= Cadillac; "3"= Oldsmobile
4 A Restraint system. "A" manual (Belts) "B" automatic (Passive belts, Airbags).
5 Z Model Y- Riviera T-Type; "L" = Eldorado; "S" = Seville
6 & 7 57 Body Style: what TYPE of car it is vehicle line, series and body style 57= Coupe; 67= Convert.1;
69= 4Dr Sedan
8 Y Engine Code See Below
9 3 Check Digit
10 C Year Code (See above)
11 E Assembly plant Linden, NJ for our cars= "E"
12 to 17 401547 Production (sequence) Number Preceded by the Division Code2

1 American Sunroof Corp. (ASC) did the Factory Authorized conversions for the Convertible Models. VIN Numbers for their cars are "67". Hess and Eisenhardt also did conversions and the VIN Numbers for their cars are "57", the same as the 2Dr Coupes.

2 For the Seville, the Production number was preceded by the code "68" to differentiate it from the Eldorado which was "6".

Engine Codes for 1981 - 1985

  • 3- 231ci V6 Turbo 4-bbl 1981-1983
  • 4- 252ci V6 4-bbl
  • Y- 307ci V8 4-bbl
  • N- 350ci V8 Diesel
  • 9- 368ci V8 DFI Cadillac Variable Displacement (8-6-4) 1981 Only
  • 9- 231ci V6 Turbo SFI 1984-1985
  • 8- HT4100 V8 DFI

This is the breakdown for a 17 place VIN:

1st to 3rd Characters - World Manufacturer Identifier (WMI)

Please note: the letter "I" as in indigo, the letter "O" as in orange, and the letter "Q" as in queen are NOT found in any VIN Numbers.

The first character represents the country of manufacture, and can be a letter or a number, each signifying a different country. For the 79 to 85 GM E-bodies it is of course the number "1" for the USA.

The second character represent the manufacturer, also known as the make. G = All General Motors vehicles.

The third characters represent the Division (Buick, Cadillac, or Oldsmobile,)

4th to 8th characters - VDS - Vehicle Descriptor Section. These 5 characters occupy positions 4 through 8 of the VIN and may be used by the manufacturer to identify attributes of the vehicle. They identify vehicle features such as body style, engine type, model, series, etc.

The fourth character is the type of restraint system.

In the above example, "A" represents a manual restraint, such as belts that have to be manually connected. A "B" would be for an automatic system such as passive restraint belts and / or airbags.

The fifth, sixth & seventh characters are the vehicle line, series and body style.

The eighth character is the engine type.

9th Character - The check digit character can best be described as identifying the VIN accuracy.

The tenth character represents the year of the car.

The eleventh character indicates the assembly plant.

Characters 12-17 represent the vehicle's unique fingerprint. It is these six digits which make every single vehicle in the world different.

Link for complete VIN info: Vehicle Identification Number - VIN Numbers

A check digit shall be part of each vin (since 1981) and shall appear in position nine (9) of the VIN on the vehicle and on any transfer documents containing the vin prepared by the manufacturer to be given to the first owner for purposes other than resale. Thus, the vins of any two vehicles manufactured within a 30 year period shall not be identical. The check digit means a single number or letter "x" used to verify the accuracy of the transcription of the vehicle identification number.

After all other characters in the VIN have been determined by the manufacturer the check digit is calculated by carrying out a mathematical computation specified. This is based on vin position, sample vin, assigned value code, weight factor and multiply assigned value times weight factors. The values are added and the total is divided by 11. The remainder is the check digit number. The correct numeric remainder - zero through nine (0-9) will appear. However, if the remainder is 10 the letter "X" is used to designate the check digit value/number.

An Auto VIN Decoder breaks down the unique alphanumeric sequence known as a Vehicle Identification Number, which is a car's fingerprint. Each and every automobile on the road has its own 17-character VIN, and it is this identification number that is used to generate a Vehicle History Report, also known as a VIN check.

The VIN check taps into millions of DMV records and reveals all of the available history for a particular vehicle, including any hidden problems, odometer readings, ownership transfers and more. It is an absolute must for used car buyers, as it tells you everything you need to know about the vehicle.