What Precautions Should Be Taken When Operating a Mobile Crane in Direct Sunlight?

When mobile cranes (rubber-tired cranes / RTGs) operate in high-temperature, sun-drenched environments, the primary risks include: tire blowouts, hydraulic system overheating, electrical component degradation, brake fade, and heatstroke among personnel. Below, we have compiled the most practical precautions—organized by system—that can be applied directly in the field.

I. Tires and Travel System (The Most Critical Risk in Direct Sunlight)
**Strictly Monitor Tire Pressure**
Tire pressure rises significantly after exposure to direct sunlight; strictly avoid inflating or deflating tires while they are hot.
Check tire pressure before operations begin and again during the midday break to prevent excessive pressure, which can lead to blowouts during high-speed travel.
**Tire Cooling and Protection**
Avoid prolonged idling in one spot or steering maneuvers while stationary under the scorching sun, as this generates intense heat through tire friction.
When parking for extended periods, seek shade whenever possible or cover the tires with protective covers to prevent the rubber from aging and cracking.
**Avoid Sudden Braking and Sharp Turns**
In high temperatures, tire grip diminishes and braking distances increase; sharp turns can easily lead to skidding, uneven tire wear, or blowouts.
II. Hydraulic System (Most Prone to Failure in High Heat)
**Control Oil Temperature**
The combination of direct sunlight and continuous operation can very easily trigger high-temperature alarms within the hydraulic system.
If the oil temperature exceeds **60°C**, stop operations temporarily to allow the system to cool down; strictly avoid forcing the machine to operate under heavy loads at such temperatures.
**Hydraulic Fluid and Filters**
Use high-temperature-resistant, anti-wear hydraulic fluid; check the fluid level and condition in advance to prevent foaming or emulsification.
Ensure that the radiator and filter screens remain clean and free of obstructions to guarantee efficient heat dissipation.
**Avoid Pressure Buildup and Prolonged Load-Holding**
In sun-drenched environments, sustained pressure buildup within the hydraulic system causes rapid temperature spikes, leading to seal degradation, oil leaks, and reduced operational power.
III. Engine / Power System
**Dual Monitoring of Water and Oil Temperatures**
Direct sunlight can easily cause the engine coolant to "boil over" (overheat); if the water temperature rises above normal levels, immediately reduce the load and let the engine idle to facilitate cooling.
**Clean the Cooling System**
The surfaces of the radiator, intercooler, and oil cooler tend to accumulate dust and debris (such as cottonwood fluff); these components must be thoroughly cleaned before operating in high-temperature conditions.
**Fuel and Battery**
Ensure the fuel tank cap seal is intact to prevent the evaporation and leakage of fuel vapors caused by high temperatures.
Keep the battery out of direct sunlight; high temperatures accelerate electrolyte loss, cause the battery casing to swell, and drastically reduce its service life. IV. Braking System (Safety: The Paramount Priority)
Preventing Brake Fade
Under high-temperature driving conditions, the performance of both service brakes and parking brakes may deteriorate; when traveling over long distances, avoid frequent intermittent braking.
Checking Brake Fluid
High temperatures can easily cause vapor lock, leading to soft brakes or brake failure; perform a test brake prior to operations to verify functionality.
Parking Brake
When restarting the vehicle after prolonged exposure to direct sunlight, release the brake and move forward slowly first to prevent the brake shoes from sticking due to high heat.
V. Steel Structures, Wire Ropes, and Lifting Gear
Wire Ropes
Prolonged sun exposure combined with high temperatures accelerates the drying out of lubricant grease; apply high-temperature-resistant grease promptly as needed.
Avoid subjecting wire ropes to sudden loads immediately after sun exposure to prevent brittle fracture or structural damage.
Steel Structures and Paintwork
High temperatures exacerbate thermal expansion and contraction, accelerating material fatigue; pay particular attention to inspecting welds, pins, and connection plates.
Seals and Hoses
Rubber hoses and sealing rings are prone to hardening and cracking under prolonged sun exposure; specifically check for any signs of oil leakage or bulging.
VI. Electrical System (Prone to Short Circuits and Malfunctions)
Control Cabinets and Junction Boxes
Direct sun exposure can cause extreme internal temperatures and condensation (due to significant day-night temperature fluctuations) within cabinets, leading to short circuits or signal drift.
Cables and Plugs
The outer sheathing of cables can age, harden, and crack under exposure; inspect for any signs of damage or exposed wiring.
Sensors and Limit Switches
High temperatures may increase the margin of error for load sensors and height limit switches; verify these readings prior to commencing operations.
VII. Cab Environment and Personnel Safety (High Heat Increases Risk of Error)
Ensure Ventilation and Cooling
The cab's air conditioning system must be fully functional; high temperatures can induce driver fatigue and slow reaction times.
Avoid Continuous, High-Intensity Work During Peak Heat Hours
Implement a rotation schedule for rest breaks to prevent heatstroke and maintain concentration, thereby avoiding operational errors caused by inattention.
Slip and Burn Prevention
Handrails and control levers within the cab can reach extremely high temperatures after prolonged sun exposure; take precautions to avoid burns.
VIII. Key Operational Guidelines
Perform a dry run (unloaded test) prior to lifting to confirm that all hoisting, luffing, slewing, and traveling functions are operating normally.
Strictly prohibit overloading or lifting loads at an angle (side-pulling); high temperatures compromise the overall stability of the equipment.
In conditions where strong winds coincide with intense sun exposure, do not attempt hazardous operations; tire-mounted cranes have a high center of gravity and are particularly susceptible to instability. Extended Parking:
Retract the boom and hook, deploy outrigger pads (if required), cut off the main power supply, and engage the parking brake.