The date code is on the passenger side of the engine, on the block, just forward and up from the distributor on a machined flat surface.
The digits of the code identify:
- 1st Digit-The year (8 = 1998).
- 2nd & 3rd Digits-The month (01 – 12).
- 4th & 5th Digits-The engine type/fuel system/compression ratio (MX = A 4.0 Liter (242 CID) 8.7:1 compression ratio engine with a multi-point fuel injection system).
- 6th & 7th Digits-The day of engine build (01 – 31).
FOR EXAMPLE: Code * 801MX12 * identifies a 4.0 Liter (242 CID) engine with a multi-point fuel injection system and 8.7:1 compression ratio that was built on January 12, 1998.