LO 6-1 Identify and describe the major safety hazards associated with engine service and maintenance
| Site: | CDX Learning Systems |
| Course: | DE Section 2-1: Engine Blocks and Cylinder Heads |
| Book: | LO 6-1 Identify and describe the major safety hazards associated with engine service and maintenance |
| Printed by: | Guest user |
| Date: | Thursday, 5 November 2026, 7:44 PM |
1. Types of Hazards Associated with Engine Service
LO 6-01: Identify and describe the major safety hazards associated with engine service and maintenance. |
Types of Hazards Associated with Engine Service
A workplace hazard refers to any workplace conditions that have the potential to cause damage to equipment and vehicles, injure workers, and cause adverse health effects or death. Hazards from working on commercial vehicles can generally be categorized as those arising from:
- Moving, lifting, and storing vehicles and accessing the engine compartment in a shop environment
- Welding, cutting, grinding, and working with power tools, booms, and hoists (shop service activities)
- Being exposed to hazardous chemicals such as solvents, fuel and fuel additives, and battery electrolyte
- The engine as a source of ignition
- Engine exhaust emissions and hot parts
- Coming in contact with energy in moving parts
- Storage or transmission of hydraulic, pneumatic, mechanical, or electrical energy
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Hazard management involves different methods or strategies to eliminate or control the threat any hazard poses Figure 2. For example, PPE may be used to prevent eye or foot injuries. Other hazards are controlled through elimination or isolation of hazards, engineering, or administrative methods. Technicians and supervisors have different duties but share the responsibility of identifying and implementing effective methods to manage shop hazards. It is particularly important for experienced workers to understand that novice technicians have not developed the skills necessary to identify and anticipate hazards, nor do they have the experience needed to minimize the potential dangers to themselves and others; this cannot be overstated. To help remedy this situation, these next sections will examine a few of the most common shop hazards and control methods to create a safe work environment when performing engine-related service. This coverage of safety-related topics is not comprehensive and requires further detailed training at a shop level. |
FIGURE 06-2: Commercial vehicle repair facilities have an above-average number of hazards. Note the potential hazards that are effectively managed in this bus repair shop. |
©2026 - CDX |
1.1. Servicing Vehicles in Shop Environments
LO 6-01: Identify and describe the major safety hazards associated with engine service and maintenance. |
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Servicing Vehicles in Shop Environments Instruction on the safe use of tools and equipment and the safe entry/exit and handling of large, heavy commercial vehicles is vital. It is imperative that technicians are adequately familiar with and skilled enough to operate a vehicle’s steering and braking systems to ensure the safe movement of vehicles in and out of a shop and to road test them, if necessary Figure 3. Cab controls for park and emergency air brakes on straight trucks, tractors, and trailers are unique, and new technicians must be very familiar with the operation of the brake system before moving these vehicles. Unfortunately, more than a few new workers have caused severe damage to vehicles as well as to shop facilities because they could not properly operate a truck or bus. Had these skills been correctly taught and evaluated by a supervisor, these incidents may have been avoided. Never undertake moving a vehicle unless you are confident that you can properly handle it or have received instruction prior to operating the vehicle. Often, when a vehicle shows up for service or repairs, safety systems such as brakes and steering may be defective or not work correctly. This explains why it is just as important to verify the correct operation of these systems prior to moving a vehicle as it is to competently move one. |
FIGURE 06-3: Truck and bus cabs have many more controls for vehicle systems than automobiles. |
When moving a vehicle, important things to remember include:
- Completely inspect around and beneath a vehicle to confirm that the path is clear of objects and personnel. Check that the brakes can apply, or press the brake pedal and verify pedal pressure before moving the vehicle.
- Always maintain three points of contact when climbing into a vehicle. Either two feet and one hand or two hands and one foot Figure 4.
- Place seat covers, mats, or tools in the vehicle before entering if your hands are also needed to climb into it.
- Clean boots of mud, snow, or grease before climbing into a cab.
- Verify that the shop door is open enough to allow the vehicle to enter and exit.
- Request all bystanders in and around the vehicle to move and remain in a safe area until the vehicle has come to a complete stop.
- Move a vehicle at a low speed and in low gear, particularly if it is moving up or down ramps.
- Use a second person as a guide or spotter when moving the vehicle in reverse, around blind corners, or down narrow paths Figure 5.
- Do not allow anyone to walk between a moving vehicle and a stationary object, such as another vehicle or a wall.
- Park the vehicle on a level, hard surface and then immediately place purpose-made wheel chocks to block the wheels from moving in both forward and reverse directions to prevent movement during servicing.
- Do not support a vehicle or machine on only hydraulic jacks, hoists, or hydraulic cylinders. Use correctly rated safety stands or purpose-made support blocks. Hoisted vehicles should rest only on mechanical locks or on purpose-made safety stands Figure 6 and Figure 7.
- Use a cab or hood lock after raising cabs and hoods to prevent them falling while working on the vehicle Figure 8. Tilt-cab vehicles will use purpose-made support rods provided by the original equipment manufacturers (OEM) that are locked in place to prevent a cab from falling and crushing someone while they are working on an engine.
As part of these procedures, respectfully care for a customer’s vehicle by installing seat covers and protective floor mats before beginning any service work, and install seat covers before entering the cab for any reason. Hands should be cleaned first or gloves worn when entering a cab. This prevents the transfer of dirt, lubricant, and grease onto the steering wheel and upholstery.
FIGURE 06-4: A warning decal on the doorjamb of a Class 8 tractor providing entry instructions. |
FIGURE 06-5: A clean, tidy, brightly lit shop, with signage, mirrors, and safety cones to alert others of potentially hazardous work areas. |
FIGURE 06-6: A lifting device must rest on a mechanical lock and should not be supported by only a hydraulic or pneumatic column. |
FIGURE 06-7: Select a safety support stand that exceeds the weight requiring support. Note the decal identifying the stand’s maximum weight capacity. |
FIGURE 06-8: A safety latch on the hood strut usually automatically locks in place when the hood is lifted and must be manually released to close. |
©2026 - CDX |
1.2. Video: Shop Safety Equipment
LO 6-01 Video: Shop Safety Equipment |
©2026 - CDX |
1.3. Video: Accident Prevention
LO 6-01 Video: Accident Prevention |
©2026 - CDX |