Just what can the VIN (Vehicle Identification Number) or chassis number tell us? Well, quite a lot actually, which is why it can be so important when specifying parts for your car.
Chassis numbers have probably been around as long as cars themselves and once were a simple serial number. However as time went by they started to form part of the vehicle's identity and became the beholders of important information. The "revolution" really started post-war when manufacturers needed to differentiate between their expanding model ranges. Quite often letters were added to basic numerical codes which added greater scope to the information that could be stored without becoming too unwieldy.
Initially the style & format of the numbers were very much down to the manufacturer and in the case of General Motors varies between the different divisions-this really reflects the autonomy they enjoyed before "badge-engineering" really kicked in. This "free for all" finished in 1980, since from '81 onwards a worldwide system was adopted that dictated that specific parts of the VIN, as it became known, were strictly controlled. We'll save that for later though.
So, just what can we learn from an early VIN? Generally, they all have a sequence number at the end-this is equivalent to the number of cars a particular plant produced during the model year. This production plant also usually appears as a letter code.
They will also have some form of identification of that model year. Fortunately that will be usually be a single digit, but beware as sometimes the digits were repeated for the 60's and the 70's. This is obviously very important as would be the engine type used. Again, in many cases this will appear as a letter or number code, but beware. GM, for example during the 60's only differentiated between six cylinder & eight cylinders in the VIN-not giving an explicit cubic inch displacement. They did this by changing code numbers to reflect a particular model line and body style. Again, body style and model code information is featured in most early chassis numbers.
Let's take some specific examples of pre-1981 cars to see what we can learn:-
Starting with a 1958 Cadillac, this is what (and where) to look for information:
Cadillac 1958
By the 1950's things were getting better, but not that much. The VIN has 9 digits and is located on the front face of the left door lock pillar.
58F001234
58.......... Model Year, 1958
F........... Body style, Series 62 Convertible
001234.. Sequence number
However, the Fisher body plate found on the firewall reveals a
great deal more information.
Style No. 58 6267X
Body No. 1234
Trim No. 60
Paint No. 30
58.......... Model year,1958
62.......... Series 62
67X....... Convertible coupe, 2-dr
1234...... Production sequence
60.......... Grey/Black/White cloth/leather
30.......... Acadian Green
Ford Cars 1965-1980
Moving on to the 1960's, when various engine options became available, this information also started to be incorporated. The VIN has 11 digits, located on the vehicle certification plate or label attached to the lock face of the drivers door.
6y83Z100551
6........... Model year, 1965
Y........... Plant code, Wixom, MI
83.......... Body style, Thunderbird 2-dr HT
Z........... Engine code, 8-cyl 390CID 4V
100551.. Sequence number
Chevrolet Cars 1969-1980
Not so much change in the 70's, but evolution is clearly happening. The VIN has 13 digits, found on a plate located on top of the dash-board, at the base of the windshield on the driver's side and visible from outside the vehicle.
1L47L8S123456
1........... GM division, Chevrolet
L........... Series code, Impala
47.......... Style, 2-dr Coupe, 6 passenger
L........... Engine code, V-8 350CID 4V
8........... Model year, 1978
S........... Assembly plant, St Louis
123456.. Sequence number
Thus until 1980, manufacturers could do pretty much as the pleased. However, in 1981 things really started to change.
The standardisation of Vehicle Identification numbers was originally described in ISO Standard 3779 in February 1977 and last revised in 1983. In North America, the regulation came into force starting with the 1981 model year.
The vehicle identification number is divided into four parts: the World Manufacturer's Identification ( WMI - three characters); the Vehicle Description Section ( VDS - five characters); the check digit; and the Vehicle Identification Section ( VIS - eight characters). When decoded, the VIN tells the country and model year; make, model and serial number, assembly plant and dependent on the manufacturer, some vehicle specifications. In order to avoid misreading, the letters "I", "O" & "Q" are not valid for use within a VIN.
To study these sections in detail, let's look at a typical VIN:-
1G1FP21F9ML109712
The WMI - in this instance 1G1 - can be decoded as follows:-
1 = Country of manufacture, North America
G = Manufacturing company, General Motors Corporation
1 = Manufacturing division, Chevrolet
The VDS - FP21F - also divulges considerable detail:-
F = Body code, Camaro
P = Model code, Sport coupe
21 = Body style, 2-door coupe
F = Engine code, 305 Tuned Port Injection
Although all VIN's conform to this general pattern, the VDS is completely at the manufacturer's discretion. However, although not a standard the eight digit will usually identify the engine fitted which is one of the more vital pieces of information.
The check digit was instigated as a way for the validity of a particular VIN to be determined by appropriate authorities. The number is derived from an algorithm calculated from numeric values assigned to each letter and their position within the VIN. The resulting calculation is divided by 11 and the remainder (0-10) is the check digit, the letter X being used for a remainder of 10.
The digits of the VIS are used to identify:-
M = Model year, 1991
L = Assembly plant, Los Angeles
109712 = Numerical sequence number, 9712th vehicle built for 1991 model year.
The assignment of letters to the model year actually started in 1980 (A) and continued through to 2000 (Y). The digits 1-9 will be used until 2009. In 2010, thirty years after introduction, (A) will be used again.
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