What Causes a Car's Exhaust Pipe to Turn Red?
2 Answers
Reasons for a car's exhaust pipe turning red: 1. Lean air-fuel mixture; 2. Delayed ignition timing; 3. Exhaust valve not sealing properly; 4. Malfunction in the electronic control system coordination. Solutions: 1. Adjust the air-fuel mixture concentration; 2. Inspect and adjust the valve clearance; 3. Adjust the ignition or fuel injection timing. Under normal operation, the temperature of an engine's exhaust pipe should not be excessively high. Only when the engine operates under heavy load for an extended period will the exhaust pipe turn red. If the fuel injection timing is excessively delayed, it not only slows down the combustion speed but also leads to incomplete combustion, causing diesel to burn in the exhaust pipe during the later stages of injection, thereby increasing the exhaust temperature.
Back when I drove my old truck, I once encountered a glowing red exhaust pipe. This usually happens when the air-fuel mixture is too rich—meaning too much fuel is injected without enough air, causing unburned fuel to reach the exhaust pipe and continue burning, generating intense heat. Also, issues with the ignition system, like worn spark plugs or incorrect ignition timing, can lead to incomplete combustion and a sharp rise in exhaust pipe temperature. Another thing to check is whether the exhaust pipe is clogged with carbon deposits or debris, trapping heat and causing it to glow red. This is no joke—I nearly had a fire that time, and it was terrifying! My advice: shut off the engine immediately and take it to a reputable repair shop to inspect the oxygen sensor, air-fuel ratio, or intake system. Regular maintenance of spark plugs and fuel lines is also key to preventing small issues from becoming big problems. Don’t cut corners or try DIY fixes—it’s not safe.
