Dealing with a Stuck Coolant Plug on the Bobcat T190

[MikePhua]

Development History of the Bobcat T190
The Bobcat T190 compact track loader was introduced in the early 2000s as part of Bobcat’s push to expand its lineup of mid-sized tracked machines. Manufactured by Bobcat Company, a division of Doosan Group since 2007 and originally part of Melroe Manufacturing, the T190 was designed to bridge the gap between the smaller T140 and the heavier-duty T250. With a rated operating capacity of 1,900 lbs and a 66-hp diesel engine, the T190 quickly became a favorite among landscapers, contractors, and rental fleets.
By 2010, Bobcat had sold over 100,000 compact track loaders globally, with the T190 accounting for a significant portion of that volume. Its popularity stemmed from its balance of power, maneuverability, and compatibility with a wide range of attachments. However, like many compact machines, the T190’s engine compartment is tightly packed, which can complicate routine maintenance tasks—especially when dealing with components like the coolant drain plug.
Terminology Annotation

• Coolant Plug: A threaded fitting, typically located at the base of the engine block, used to drain engine coolant during service.
  
• Allen Hex: A type of recessed fastener head requiring an Allen wrench (hex key) for removal.
  
• Motor Mount: A structural bracket that secures the engine to the frame, often obstructing access to nearby components.
  
• Radiator Hose: A flexible tube that carries coolant between the engine and radiator; loosening the lower hose can serve as an alternative drain point.
  

Access Challenges with the Coolant Plug
On the 2007 Bobcat T190, the coolant plug is positioned behind the oil filter and adjacent to the motor mount, making it difficult to reach with standard tools. The plug itself is an Allen hex type, which requires a hex key or Allen socket for removal. Due to its location, even experienced technicians may struggle to apply sufficient torque without removing surrounding components.
This design reflects a broader trend in compact equipment, where space constraints often force manufacturers to prioritize packaging over serviceability. While this improves machine dimensions and visibility, it can frustrate mechanics during routine fluid changes.
Alternative Drain Methods
When the coolant plug is inaccessible or seized, several alternative methods can be employed:

• Loosening the lower radiator hose: This is the most straightforward workaround. By removing the clamp and gently pulling the hose, coolant can be drained from the system without touching the plug. This method is widely used in field service and emergency repairs.
  
• Pumping coolant from the reservoir: Using a fluid extractor or siphon pump, coolant can be removed from the top of the system. While this doesn’t fully drain the block, it’s useful for partial fluid changes or when replacing the radiator.
  
• Removing the water pump bolt: In some cases, loosening a bolt on the water pump housing allows coolant to leak out. This method should be used cautiously, as it may require new gaskets or sealant upon reassembly.
  

Preventative Measures and Recommendations
To avoid future issues with stuck plugs:

• Apply anti-seize compound to plug threads during reinstallation
  
• Use high-quality coolant with corrosion inhibitors to prevent thread binding
  
• Inspect plug accessibility during major service intervals and consider relocating components if feasible
  
• Replace Allen hex plugs with external hex plugs for easier access
  

For long-term maintenance, consider installing an aftermarket drain valve in the lower radiator hose. These valves allow tool-free draining and reduce wear on factory fittings.
A Story from the Field
In 2018, a landscaping crew in Georgia faced a similar issue with their T190 during a spring tune-up. The coolant plug was inaccessible due to a rusted motor mount bracket and a seized Allen head. Rather than dismantling the engine bay, the crew opted to loosen the lower radiator hose and install a ball valve inline for future service. The modification cost under $30 and saved hours of labor in subsequent seasons. The crew later retrofitted the same solution to their T250 and T300 units.
Industry Trends and News
As compact equipment continues to evolve, manufacturers are beginning to prioritize serviceability. In 2024, Bobcat introduced a new series of loaders with modular engine bays and external fluid ports, allowing technicians to perform full fluid changes without crawling under the machine. These updates were driven by feedback from rental fleets and independent mechanics who cited downtime and labor costs as key concerns.
Meanwhile, aftermarket suppliers have begun offering service kits for older Bobcat models, including flexible drain hoses, plug adapters, and corrosion-resistant fittings. These kits are especially popular among fleet managers maintaining legacy equipment beyond its warranty period.
Conclusion
A stuck coolant plug on the Bobcat T190 is a common but manageable issue. With limited access and tight engine compartments, alternative drain methods such as loosening the radiator hose or using a siphon pump can save time and effort. By adopting preventative measures and considering minor retrofits, operators can streamline future maintenance and extend the life of their machines. As the industry shifts toward more service-friendly designs, even legacy models like the T190 can benefit from modern solutions and field-tested ingenuity.