Locating the Serial Number on a Caterpillar D6K Dozer

[MikePhua]

Why Serial Numbers Matter
Serial numbers are the backbone of equipment identification. On Caterpillar machines like the D6K dozer, the serial number—also known as the Machine Identification Number (MID) or Product Identification Number (PIN)—is essential for ordering parts, verifying service history, and confirming model year. Without it, even experienced dealers may struggle to match components accurately, especially on machines with mid-series updates or regional variations.
D6K Model Background and Production History
The Caterpillar D6K was introduced in the mid-2000s as a mid-size dozer optimized for grading, site prep, and forestry work. It filled the gap between the lighter D5 and heavier D6N models. Early D6K units featured mechanical fuel systems and basic electronics, while later versions adopted Tier 4 emissions controls and integrated GPS-ready platforms. The D6K was produced in multiple configurations, including XL (extra long track) and LGP (low ground pressure), each with unique undercarriage and blade setups.
Typical Serial Number Locations
On the D6K, the serial number is usually stamped or affixed in one or more of the following locations:

• Left rear frame rail: Look near the final drive housing, just above the track. This is the most common stamped location.
  
• Right side of the engine block: Some units have an engine serial plate riveted near the fuel injection pump.
  
• Inside the cab: Check the operator’s console or fuse panel area for a printed label.
  
• Radiator guard or front crossmember: Occasionally, a secondary plate is mounted near the front grille or behind the blade lift cylinder.
  

The serial number typically begins with a three-letter prefix (e.g., KAL, JAK, LGP) followed by a six-digit sequence. This prefix identifies the build series and configuration.
Challenges in Locating the Number
Over time, serial plates can be obscured by:

• Paint overspray during refurbishment
  
• Mud and debris accumulation in field conditions
  
• Wear and corrosion on exposed frame surfaces
  
• Cab replacement or modification, which may remove interior labels
  

In one case, a forestry D6K had its cab replaced after a rollover. The new cab lacked the original serial label, and the frame stamp had been painted over during rebuild. The operator eventually found the number etched faintly under the left rear step after wire brushing the area.
Alternative Identification Strategies
If the serial number is missing or unreadable:

• Use the engine serial number to narrow down build year and configuration
  
• Check hydraulic pump tags for manufacturing dates
  
• Contact Caterpillar with component serials (e.g., transmission, final drive) to trace machine identity
  
• Review past service records or dealer invoices that may list the full PIN
  

Dealers can often cross-reference component serials to reconstruct the machine’s identity, especially if it was sold through an authorized channel.
Recommendations for Owners

• Photograph and record the serial number in multiple locations
  
• Etch or stamp a backup number discreetly on the frame
  
• Keep a laminated copy of the PIN in the cab for quick reference
  
• If repainting, mask off the serial plate and avoid grinding near stamped areas
  

Conclusion
Finding the serial number on a Caterpillar D6K dozer may require persistence, especially on older or refurbished units. Knowing where to look—and what to look for—can save hours of frustration and ensure accurate parts ordering. The D6K remains a versatile and widely used machine, and maintaining clear identification is key to keeping it productive and serviceable.