Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Engine Identification
The Vehicle Identification Number (VIN) is located on the upper left side of the dash and is visible through the windshield. The eighth character identifies engine size.
| Application | VIN Code |
|---|---|
| 4.0L 6-Cylinder PFI | S |
Some engines are manufactured with oversize or undersize components. These engines are identified by a letter code stamped on a boss between ignition coil and distributor. Letters are decoded as follows:
- "B" indicates all cylinder bores are .010" (.25 mm) oversize.
- "C" indicates all camshaft bearing bores are .010" (.25 mm) oversize.
- "M" indicates all main bearing journals are .010" (.25 mm) undersize.
- "P" indicates one or more connecting rod journals are .010" (.25 mm) undersize.
- "PM" indicates all main journals and one or more rod journal are .010" (.25 mm) undersize.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.