What causes the Changan CS75's exhaust valve to fail and burn engine oil?
4 Answers
There are several reasons why the Changan CS75's exhaust valve may fail and cause engine oil burning: 1. Improper maintenance: When the exhaust valve is damaged, it cannot control the amount of exhaust gas recirculation. Excessive exhaust gas participating in recirculation will affect the ignition and performance of the air-fuel mixture, thereby impacting the engine's power, especially during idle, low speed, small load, and cold start conditions. The recirculated exhaust gas will significantly affect engine performance. 2. Fuel quality issues: Sudden exhaust valve failure after using low-quality gasoline or fuel additives can lead to engine oil burning and severe blue smoke from the exhaust. The reason is that the exhaust valve also functions as an oil-gas separator. Under normal operation, it only draws in exhaust gases and not oil. When the exhaust valve is damaged and loses its oil-gas separation function, it will draw in oil along with the exhaust gases, allowing oil to enter the intake manifold and combustion chamber, resulting in oil burning and severe blue smoke from the exhaust.
I've been driving a Changan CS75 for eight years, and a faulty PCV valve can indeed cause excessive oil consumption. When the valve is clogged or cracked, oil vapors from the crankcase enter the engine and get burned, leading to a rapid increase in oil consumption. A while ago, my car started emitting blue smoke, and the fuel consumption suddenly became ridiculously high. After inspection, it turned out to be a valve issue. There are many reasons for this, such as aging oil accumulating dust, or driving in dirty environments that make it easier for impurities to build up. Additionally, components naturally wear out over time. If not repaired promptly, internal engine wear can worsen, piston rings may fail, and in the worst case, the car could break down in the middle of the road. After fixing it, I've made sure to change the oil and air filter regularly to prevent similar issues. Car maintenance is all about nipping problems in the bud—it saves money and hassle.
I'm very interested in automotive mechanics. The principle behind the Chang'an CS75's PCV valve failure causing oil burning is quite simple: when that valve in the PCV system fails, pressure imbalance sucks engine oil into the intake manifold and combustion chamber where it gets burned. Common causes include valve blockage or spring fatigue, especially after driving in dusty areas where debris accumulates. Symptoms include blue smoke from the exhaust and oil consumption doubling. A simple test is checking for vacuum changes at the oil filler cap during idle. Fixing it isn't expensive - just replace the valve. But delaying repairs may lead to severe carbon buildup or even valve damage, multiplying repair costs. I always remind myself to watch for unusual engine noises and dipstick level drops - early intervention saves trouble.
From a safety perspective, a damaged exhaust valve in the Changan CS75 leading to oil burning is highly dangerous. A malfunctioning valve can cause engine oil to be sucked into the combustion chamber, resulting in unstable power or smoke emission. The primary cause is often neglected maintenance leading to valve clogging and aging. Failure to address this issue promptly can result in engine overheating and a high risk of fire. My advice: inspect immediately upon noticing symptoms, don't skimp on repairs.
