What Is a Bobcat Doosan Engine? (Diesel Specs)
A Bobcat Doosan engine is a diesel engine fitted to certain Bobcat machines, but the name alone does not identify its exact model or specifications. As a reference, the Bobcat S650 skid-steer loader uses a four-cylinder, 2.4 L turbocharged D24 diesel rated at 74 hp at 2,800 rpm. Always confirm your machine’s model and serial number before using these figures.
Could your manual mention a “Doosan engine” without making clear which diesel you have? The key is to separate the engine maker or name from the machine’s exact configuration. I use the S650 with the D24 engine below as a specific reference, not as a specification for every Bobcat loader.
Identify the Bobcat Engine and Confirm Model Compatibility
A “Bobcat Doosan engine” generally means a diesel engine associated with Doosan and installed in a Bobcat machine. It is not one universal engine specification. The engine model, emissions equipment, and service requirements can vary by machine, year, and serial-number range.
For the S650/D24 configuration covered here, the reference specifications are:
| Item | S650/D24 reference |
|---|---|
| Engine model | Bobcat D24 |
| Engine type | Four-cylinder, liquid-cooled diesel |
| Displacement | 2.4 L (148 in³) |
| Aspiration | Turbocharged |
| Rated engine power | 74 hp (55.2 kW) |
| Published rated speed | 2,800 rpm |
Displacement is the combined volume swept by the pistons inside the cylinders. Turbocharged means the engine uses a turbine-driven compressor to push more air into the engine. Rated power is a published engine output figure; it is not a promise that every machine setup, condition, or work task will deliver the same performance.
Why model and serial numbers matter
The S650/D24 figures are a model-specific reference. Do not assume they apply to another S650 year, a different Bobcat model, or an engine that looks similar. Bobcat may use different engine models or revisions, and emissions equipment and service procedures can also differ.
Find the machine identification plate and engine label, then match the model and serial number to the correct operator and service manuals. If you are checking a used machine, replacing an engine, or ordering parts, match the engine identification too. A shared brand name does not prove that parts, wiring, controls, or mounting points are interchangeable.
The 2,800 rpm figure is the published rated speed for this reference configuration. It is not an adjustment target. Do not change the governor or alter emissions equipment to try to reach a different speed or power output. Use the serial-specific service procedure and qualified service personnel for engine adjustments.
What the numbers do and do not tell you
The table gives a quick way to recognize the reference engine. It does not provide every service limit or maintenance specification. Oil capacity, approved oil grade, fuel requirements, filter part numbers, coolant type, and other details should come from the manual for your exact machine and engine.
Rated engine power also does not describe every part of loader performance. A skid-steer’s work depends on the machine’s full design and condition, not just its engine rating. If a machine feels weak, do not assume that changing engine speed or fitting a different engine is the answer. Check for warning indicators and follow the machine’s diagnostic guidance.
Pre-Operation Checks and Safe Field Operation
Before starting, confirm that the machine is in a safe position and that its basic checks are complete. For an S650/D24, the engine figures above can help identify the reference configuration, but the operator’s manual for your serial number controls the starting and operating steps.
1. Identify and inspect
Park on level ground. Lower the lift arms and attachment, engage the parking brake, and follow the manual’s instructions for securing the machine. Before starting, look for fluid leaks, damaged wiring, loose parts, and blocked cooling screens. Clear visible debris only when it is safe to do so and the machine is shut down.
Do not reach near moving parts or hot surfaces. If you find a leak, damaged wire, or loose component, do not treat it as harmless just because the engine still starts. Use the manual’s inspection guidance or have the machine checked before working.
2. Check fluids and start
Check engine oil and coolant as directed by the manual. The right time and method can depend on the system and machine instructions. Use only the fuel, oil grade, coolant, and filter specifications listed for your serial number and emissions configuration. Do not guess based on another Bobcat or a general D24 listing.
Follow the prescribed cold-start procedure. Do not use starting fluid unless the manufacturer explicitly authorizes it for that machine. An unapproved starting aid can create a serious risk of engine damage. After starting, pay attention to warning lights and unusual sounds rather than moving straight into heavy work.
3. Operate and monitor
Give cold oil time to circulate, then increase the workload gradually. While operating, watch the temperature gauge, oil-pressure warning, exhaust behavior, and any aftertreatment indicators fitted to your machine. Follow the manual’s instructions for interpreting each warning.
Stop and investigate if a warning light appears, the engine overheats, power drops, or you hear an abnormal noise. Continuing to work under load may worsen a fault. The safe response depends on the warning and machine instructions, so avoid using a generic online threshold in place of the serial-specific manual.
If the machine has a diesel particulate filter (DPF), follow its regeneration instructions. A DPF captures soot from the exhaust and may need a regeneration process to burn that soot away. During regeneration, the exhaust area can become hot. Keep dry vegetation and other combustible material clear; do not park beside dry grass or landscaping mulch while regeneration is taking place.
Maintenance, Cooling-System Care, and Aftertreatment
Routine care protects the engine and helps you catch problems early. The exact intervals, fluid grades, filter requirements, and aftertreatment steps depend on the machine’s serial number and emissions setup, so use its service schedule rather than applying another model’s numbers.
Keep cooling airflow clear
The D24 reference is liquid-cooled, so the cooling system matters as much as the engine itself. Check the cooling screens and surrounding areas for debris, especially when working where dust, chaff, or plant matter can collect. Blocked airflow can contribute to overheating.
Inspect the system according to the manual. Do not open a hot cooling system; hot coolant can cause burns. If the machine runs hot or coolant is leaking, stop work and follow the manual’s troubleshooting steps. Do not keep operating in the hope that the temperature will fall on its own.
Follow the machine’s service schedule
Use the correct manuals and parts information for your serial number. Keep service records, including the date, engine hours, and parts or fluids used. That record can help you spot missed service and give a technician useful information.
Do not assume that a filter or fluid listed for another Bobcat is correct for yours. Engine revisions and emissions configurations can affect the required parts and procedure. If the manual does not clearly identify a specification, confirm it with a Bobcat dealer or qualified service provider before adding a fluid or ordering a part.
Treat aftertreatment warnings as operating information
Aftertreatment equipment manages exhaust emissions. A DPF is one example, but equipment can vary. Use the machine’s display and manual to understand what an indicator means and what action is required. Do not remove, bypass, or modify emissions equipment to address a warning or change engine output.
A regeneration warning is not a reason to ignore the surroundings. Keep the exhaust outlet clear of combustible debris and follow the stated parking and regeneration steps. If a warning remains after the prescribed procedure, or the machine limits power, contact a qualified service provider rather than repeatedly forcing regeneration.
Shutdown, Storage, and Seasonal Diesel-Fuel Care
A safe shutdown protects both the operator and the machine. Lower equipment, use the prescribed cool-down procedure, and check the engine area after stopping. For storage, follow the machine’s manual for fuel, battery, and service preparation instead of relying on a generic diesel-engine routine.
Shut down in a controlled way
Park safely and lower the lift arms and attachment. Follow the manual’s direction on idling or cooling before shutdown; do not assume every condition calls for the same wait. After switching off, look for leaks or fresh debris when it is safe to inspect.
Keep hands clear of hot exhaust parts and moving components. If regeneration has recently occurred, take extra care around the exhaust area. Do not remove covers or perform service until parts have cooled as directed by the manual.
Store and fuel according to the manual
For seasonal storage, use the instructions for your machine and fuel system. Fuel handling and storage needs can vary with the fuel type, climate, and length of storage. Use the fuel specified by Bobcat for your serial number, and do not mix lubricating oil into diesel fuel unless the manufacturer specifically requires it.
If the engine will not start after storage, avoid repeated attempts that conflict with the manual’s guidance. Check for simple issues only as the manual allows, and seek service if the machine shows a warning, leak, or other fault. The correct procedure matters more than a rule borrowed from a different diesel engine.
Practical compatibility scenarios
These examples show how to apply the reference without assuming all Bobcat engines match:
| Situation | What to confirm |
|---|---|
| You own an S650 and need basic engine identification | Check that the machine and engine labels match the S650/D24 reference; verify the serial-specific manual. |
| You are comparing two used Bobcat loaders | Compare each machine’s model, serial number, and engine label. Similar appearance does not establish engine or parts compatibility. |
| You are considering an engine replacement | Confirm the complete engine and machine requirements with serial-specific parts and service information. Do not assume a D24 is a drop-in replacement. |
| You see an aftertreatment warning | Read the machine’s display and manual, keep combustible material clear during regeneration, and follow the stated procedure. |
These are decision scenarios, not reports of specific engine installations. A replacement engine must match more than its displacement or name. Confirm fit, controls, emissions equipment, and service requirements through the machine’s parts and service information before proceeding.
Conclusion
For the Bobcat S650/D24 reference, the engine is a four-cylinder, liquid-cooled, turbocharged 2.4 L diesel rated at 74 hp and 2,800 rpm. Those figures identify one configuration, not every Bobcat Doosan engine. Match the machine and engine serial numbers to the right manuals before servicing, diagnosing, or replacing parts.
FAQ
Is a Bobcat Doosan engine a diesel?
Yes, the S650/D24 reference is a diesel engine. The phrase “Bobcat Doosan engine” can refer to different machine and engine configurations, so check the engine label and machine serial number.
What engine is in the Bobcat S650?
The reference configuration in this guide uses the Bobcat D24 engine. Confirm the machine’s year and serial number before treating that as the correct engine for your particular S650.
What is the Bobcat D24 engine’s displacement?
The S650/D24 reference has a displacement of 2.4 L, or 148 cubic inches.
How much horsepower does the S650 D24 have?
The published rated engine power for this reference is 74 hp, or 55.2 kW. Actual machine performance depends on the full machine and its condition.
What is the rated speed of the S650 D24?
Its published rated speed is 2,800 rpm. Do not use that figure as a governor adjustment target; follow the serial-specific service procedure.
Is every Bobcat Doosan engine a D24?
No. The name alone does not identify the engine. Bobcat machines can differ by model, year, engine revision, and serial-number range.
Can I use another Bobcat’s oil or filter specification?
Not without confirming compatibility. Use the fluid grade and filter specifications in the manual for your machine’s serial number and emissions configuration.
Does the D24 have a turbocharger?
The S650/D24 reference is turbocharged. Check the engine label and machine documentation to confirm the configuration of another Bobcat machine.
What should I do if the machine shows a DPF warning?
Follow the display and the manual’s regeneration instructions. Keep dry grass, mulch, and other combustible material away from the exhaust area during regeneration.
Can I adjust the engine to get more power?
Do not adjust the governor or alter emissions equipment to seek more speed or power. Use the manufacturer’s service procedure and qualified service personnel for engine concerns.
(This article was written by one of our staff writers, Evan Bradley. Visit our Meet the Team page.)
