Restoring Heat Flow in the Bobcat S250 Cabin

[MikePhua]

The Bobcat S250 and Its Climate Control System
The Bobcat S250 skid steer loader was introduced in the early 2000s as part of Bobcat’s high-performance S-series. With a rated operating capacity of 2,500 pounds and a turbocharged diesel engine delivering around 75 horsepower, the S250 quickly became a favorite among contractors for its power-to-size ratio and hydraulic versatility. One of its key features was the enclosed cab option with integrated heating and ventilation, designed to extend operator comfort in cold climates.
The climate control system in the S250 includes a blower motor, heater coil (also known as a heater core), ducting, and control panel. Warm coolant from the engine circulates through the heater coil, and the blower motor pushes air across the coil into the cab. Over time, this system can suffer from reduced airflow, especially if components degrade or become obstructed.
Diagnosing Low Air Volume in the Cab
A common issue in aging S250 units is low airflow through the heat vents, even after replacing the blower motor. In one case, an aftermarket blower motor was installed, but the problem persisted. The dealer later identified the heater coil as the culprit, noting that it was internally plugged and could not be cleaned effectively.
Symptoms of a plugged heater coil include:

• Weak airflow from vents despite a functioning blower
  
• Uneven heating across vent zones
  
• Audible strain from the blower motor
  
• No improvement after filter or duct cleaning
  

Plugging typically results from sediment buildup, corrosion, or degraded coolant that leaves deposits inside the coil’s narrow passages. Once blocked, the coil restricts airflow and reduces heat transfer efficiency.
Replacement Challenges and Retrofit Costs
The original heater coil for the S250, part number 6727786, is no longer available through standard channels. Bobcat has issued a retrofit kit to replace the coil, but the cost is substantial—around $500 for the kit and nearly $1,000 in labor. The installation process is labor-intensive, requiring:

• Removal of the cab interior panels
  
• Disconnection of coolant lines and electrical connectors
  
• Installation of the new coil and bracketry
  
• Reassembly and coolant system bleeding
  

Labor estimates include five hours of shop time plus miscellaneous fees, which can add up quickly. For machines nearing the end of their service life, this cost may exceed their residual value, prompting owners to consider alternative solutions.
Alternative Solutions and Preventative Measures
Operators facing heater coil failure have a few options:

• Attempt chemical flushing using a radiator flush solution, though success is limited if the coil is fully blocked
  
• Source a compatible coil from salvage yards or aftermarket suppliers, matching dimensions and inlet/outlet orientation
  
• Bypass the heater coil entirely and install an auxiliary cab heater powered by diesel or 12V electricity
  

Preventative steps to avoid future coil plugging include:

• Regular coolant changes using manufacturer-approved formulations
  
• Installing an inline coolant filter to trap debris before it reaches the heater coil
  
• Avoiding aftermarket coolant additives that may leave residue
  
• Periodically backflushing the heater circuit during maintenance
  

Field Anecdotes and Practical Advice
In Alaska, where winter temperatures routinely drop below -20°F, one operator reported that his S250’s cab heat was essential for visibility and comfort. After replacing the blower motor and still experiencing poor airflow, he discovered the heater coil was plugged. The dealer’s recommendation to install the retrofit kit came with sticker shock, but the operator ultimately opted for the repair due to the machine’s otherwise excellent condition.
Elsewhere, a fleet manager in Minnesota retrofitted several older Bobcat units with auxiliary heaters sourced from truck supply catalogs. These units, mounted behind the seat and plumbed into the coolant system, restored cabin warmth at a fraction of the OEM retrofit cost.
Conclusion
The Bobcat S250’s heater coil is a vital component of its climate control system, but age and coolant degradation can render it ineffective. When airflow drops and heat disappears, the root cause may lie deep within the coil’s passages. With OEM parts discontinued and retrofit kits priced steeply, operators must weigh the cost of repair against the value of the machine. Whether choosing a full retrofit, a salvage replacement, or an auxiliary workaround, restoring heat flow is not just about comfort—it’s about safety, productivity, and keeping the machine in service through the coldest months.