Water in Oil Without Glycol in a CAT 267B

[MikePhua]

The CAT 267B and Its Mechanical Legacy
The Caterpillar 267B is a compact track loader designed for versatility in construction, landscaping, and utility work. Introduced in the early 2000s, it featured a rubber track undercarriage system for improved traction and reduced ground disturbance. With an operating weight of around 8,000 pounds and a rated operating capacity near 2,000 pounds, the 267B was powered by a turbocharged diesel engine—typically the CAT 3024C or Perkins 804D-33T—delivering roughly 61 horsepower.
Caterpillar Inc., founded in 1925, has long been a dominant force in the compact equipment market. The 267B was part of a broader push to offer high-performance loaders with enhanced operator comfort, hydraulic responsiveness, and simplified maintenance. Though no longer in production, thousands of units remain in service globally, especially in North America.
Unusual Oil Contamination and Diagnostic Confusion
A recurring issue with one CAT 267B involved water contamination in the engine oil, despite multiple oil changes and a head gasket replacement. The problem persisted, prompting an oil analysis that confirmed excessive water content but tested negative for glycol—suggesting the intrusion was not from coolant.
This result raised questions, as conventional wisdom associates water in oil with coolant leaks, typically through a failed head gasket, cracked head, or compromised oil cooler. The absence of glycol, however, pointed to alternative sources such as rainwater ingress, condensation, or even flawed sampling techniques.
Terminology and Testing Methods

• Glycol: A chemical compound found in antifreeze, typically ethylene glycol or propylene glycol. Its presence in oil confirms coolant contamination.
  
• Crackle Test: A field method for detecting water in oil by placing a drop on a hot plate; water causes audible crackling as it vaporizes.
  
• Elemental Analysis: A lab-based technique that measures concentrations of metals and additives in oil, used to assess wear and contamination.
  

In this case, the oil sample showed elevated levels of iron and silicon after less than five hours of runtime—anomalous for such a short interval. Iron typically indicates wear from cylinder liners, rings, or valve train components, while silicon may suggest dirt ingress or sealant breakdown.
Sampling Technique and Its Impact
The sample was taken from the oil drain plug while the engine was cold. This method can skew results, as contaminants settle at the bottom and oil viscosity changes with temperature. Ideally, oil samples should be drawn using a suction gun from mid-sump with the engine at operating temperature to ensure representative fluid composition.
Cold sampling may exaggerate wear metals and water content, especially in freshly changed oil. Additionally, new oil formulations often contain trace elements like sodium, boron, and potassium, which can mimic signs of coolant contamination if not properly interpreted.
Possible Sources of Water Intrusion
Several scenarios could explain water in oil without glycol:

• Rainwater Ingress: If the machine is stored outdoors without adequate sealing, rainwater can enter through the breather, dipstick tube, or valve cover.
  
• Condensation: In humid climates or during temperature swings, condensation can form inside the crankcase, especially if the engine is not run long enough to evaporate moisture.
  
• Cracked Block or Head: Microfractures may allow water to seep into the oil without coolant involvement, particularly if the cooling system is filled with water rather than antifreeze.
  
• Oil Cooler Breach: Though inspected and deemed intact, a compromised oil cooler can allow water into the oil circuit. However, this typically results in oil appearing in the coolant due to pressure differentials.
  

Recommendations for Further Diagnosis
To pinpoint the source, technicians should consider the following steps:

• Warm up the engine, drain the oil, and pressurize the cooling system overnight. Monitor the oil pan for coolant seepage.
  
• Inspect the breather system and valve cover seals for signs of water ingress.
  
• Use UV dye in the coolant to trace leaks into the oil system.
  
• Replace all gaskets and seals with OEM-grade components, especially after head milling.
  
• Conduct a borescope inspection of the cylinder walls and water jackets.
  

If the head was warped—confirmed by a 0.006-inch milling—it could have allowed coolant to bypass the gasket seal. However, the absence of glycol complicates this theory unless the coolant used was water-based or heavily diluted.
Wear Metals and Engine History
The elevated wear metals suggest prior damage or accelerated wear. The seller claimed the bottom end had been rebuilt with new pistons, rods, and bearings, but without documentation, this remains speculative. If the engine was previously operated with water-contaminated oil, bearing surfaces and cylinder walls may have suffered, leading to increased metal content in subsequent samples.
Silicon at 13 ppm after only a few hours is particularly concerning. It may indicate residual dirt from assembly, poor air filtration, or sealant breakdown. Iron levels should be below 10 ppm at 250 hours, making the current readings disproportionately high.
Field Anecdotes and Broader Implications
One technician recalled a similar issue with a compact loader stored outdoors in upstate New York. After heavy rains, the engine oil turned milky, and analysis showed water but no glycol. The culprit was a cracked breather cap that allowed rainwater to enter during storms. Replacing the cap and relocating the machine under cover resolved the issue.
Another case involved a forestry skid steer where condensation built up due to short idle cycles in cold weather. The operator never ran the machine long enough to reach full temperature, allowing moisture to accumulate in the crankcase. A simple change in operating routine—running the engine for 30 minutes per session—eliminated the problem.
Conclusion
Water in oil without glycol in a CAT 267B presents a diagnostic puzzle that challenges assumptions about contamination sources. While coolant leaks remain a common cause, environmental factors, sampling errors, and prior damage must also be considered. Accurate oil analysis depends on proper technique, context, and interpretation. For owners and technicians, vigilance in sealing, storage, and sampling can prevent costly misdiagnoses and preserve engine integrity. The CAT 267B, like many compact machines, rewards those who combine mechanical insight with methodical troubleshooting.