Will a Faulty Exhaust Valve Affect Engine Power?

[DelTheo]

Yes, a faulty exhaust valve can affect engine power. When the exhaust valve is damaged, it cannot properly 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 output. This effect is particularly noticeable during engine idle, low-speed operation, small loads, and when the engine is cold. Exhaust Valve: The exhaust valve, also known as an oil separator or pressure control valve, is installed between the compressor outlet and the condenser inlet. Through separation, it improves the heat transfer efficiency in the condenser and evaporator. Working Principle of the Exhaust Valve: High-pressure gas (comprising gaseous working fluid and lubricating oil) discharged from the compressor enters the exhaust valve and passes through its guide vanes. The gas flows in a spiral pattern along the guide vanes, and centrifugal force and gravity separate the lubricating oil from the working fluid gas. The oil flows down along the inner wall of the cylinder. The working fluid gas passes through a multi-hole baffle and is discharged from the central pipe of the exhaust valve. The separated lubricating oil accumulates at the bottom of the oil separator and can be periodically drained or automatically returned to the compressor's crankcase via a float valve.

[DelChase]

As a veteran driver with 20 years of experience, I can tell you that a faulty exhaust valve will definitely cause a loss of power. Back when I drove trucks, I encountered this issue—going uphill, the engine felt noticeably sluggish, and even flooring the accelerator wouldn’t get the speed up. A clogged exhaust valve leads to excessive crankcase pressure, forcing oil into the combustion chamber. When carbon builds up in the cylinders and gasoline doesn’t burn completely, you lose at least 20-30% of your power. The worst part? Blue smoke starts pouring out, and your engine oil runs low within a few hundred kilometers. In my case, it even seized the piston rings. If your car suddenly feels weak and is burning oil, get the exhaust valve checked at a repair shop ASAP. Delaying it could cost you a fortune in engine repairs later.

[ElleFitz]

Last week, my best friend's Civic was always gasping for breath when accelerating. After checking forums for her, I discovered it was a faulty PCV valve—technically called the Positive Crankcase Ventilation valve, which acts like the engine's breathing valve. When it fails, the crankcase gets pressurized, like someone trying to run while covering their nose and mouth. This causes oil vapors to backflow into the throttle body, coating the entire intake system with a layer of sludge, making throttle response sluggish. The most noticeable symptom was severe idle shaking at red lights, and fuel consumption suddenly increased by 2 MPG. I suggest testing by opening the oil cap during a cold start—if it's stuck and hard to open, there's an 80% chance the PCV valve is clogged.

[DeAubrey]

Don't underestimate this small plastic valve. I've seen too many cases of cylinder scuffing due to a faulty PCV valve during my repairs. It's supposed to recirculate crankcase gases into the intake manifold for secondary combustion, but when it sticks, fresh air can't enter, causing the engine's combustion efficiency to plummet like it's oxygen-starved. Especially in turbocharged cars, you'll hear a puffing sound during boost release. Power loss is noticeable across all speed ranges, particularly when accelerating with the AC on. Most repair shops use a simple test: disconnect the hose to check if idle changes, which can determine whether it's stuck open or closed.