Yes, a loose gas cap can indeed trigger the check engine light (CEL) on your vehicle's dashboard. This occurs because the fuel system in modern vehicles is designed to be completely sealed. The purpose of this design is to prevent fuel vapors from escaping into the atmosphere, reducing air pollutants. A loose or faulty gas cap disrupts this sealed system, causing a decrease in fuel pressure and potentially allowing fuel vapors to escape. The vehicle's onboard diagnostics system (OBD-II), monitoring the integrity of this sealed system, detects the pressure drop or fuel vapor leak. In response, it triggers the CEL as a warning of a potential emission problem. Therefore, if your check engine light comes on, checking whether the gas cap is tight and properly sealed can be a simple and cost-effective first step before pursuing more complex diagnostics and repairs.

Certainly! A semi-truck engine, also referred to as a diesel engine in the context of big rigs, has a significant weight due to its design and the need for durability and power. Typically, the weight of a semi engine falls in the range of approximately 2,500 to 3,000 pounds (about 1,134 to 1,361 kilograms). This weight includes the engine block, internal components, and often attached accessories such as the alternator, starter, and turbocharger, but can vary depending on the specific model and manufacturer. Semi engines are designed to handle heavy loads over long distances, hence their substantial size and weight. This robust construction ensures they can produce the necessary horsepower and torque while maintaining reliability and longevity under strenuous conditions.

Cleaning a truck's engine not only makes it look better, but it can also run cooler, leading to more efficient performance and potential issues becoming more visible for easier fix. Here are steps for how to clean a truck engine: Materials Needed: 1. Plastic bags 2. Rubber bands 3. Engine degreaser 4. Scrub brush 5. Garden hose with spray nozzle 6. Protective gloves and eyewear 7. Compressed air (optional) 8. Engine dressing (optional) Steps: 1. Safety first: Wear protective gear such as gloves and eyewear to prevent degreaser and grime from getting on your skin or in your eyes. 2. Prepare your truck: Ensure your engine is completely cool before you begin. If the engine is warm, it could cause the degreaser to dry too quickly and be hard to rinse off. 3. Protect sensitive components: Cover parts of the engine that shouldn't get wet or could be damaged by the degreaser. This typically includes the alternator, electrical components, air intake, sensors, and distributor. Use plastic bags secured with rubber bands for this. 4. Apply the degreaser: Make sure to follow the instructions on the bottle. Some degreasers should be diluted with water before application. 5. Scrub: Use your scrub brush to gently clean areas of build-up, making sure to reach all the nooks and crannies. 6. Rinse: Use your garden hose to completely rinse off the engine and all engine bay walls. It's best to start at the bottom and work your way up to avoid recontamination. Be careful not to use high pressure which can force water into electrical connections or other sensitive components. 7. Dry: If you have an air compressor, use it to blow out any excess water. If not, use a rag to mop up excess water and leave the hood open to air dry. 8. Optional – Apply engine dressing: Some people like to apply an engine dressing after cleaning to give their engine a shiny appearance and make future cleanups easier. 9. Check your work: Before starting your vehicle, make sure all caps are on tightly (oil, brake fluid, power steering fluid, etc.) and your air filter is dry. 10. Test run: Start your vehicle and let it run for a bit. Check for any leaks or unusual noises. Then, shut it off and check fluid levels. If everything looks good, your cleaning was successful. Remember, if you're unsure about anything during this process, it's always best to consult with a professional mechanic.