5 Symptoms of a Bad PCV Valve
Is your car sputtering, losing oil, or your check engine light is on? A bad PCV valve could be to blame. Learn how to recognize the symptoms of a bad crankcase ventilation valve, a vital part of your exhaust system.
If the cause of your car’s problems is indeed a faulty PCV valve, consider yourself lucky. In terms of replacement cost, this is one of the least expensive parts to replace and most people can do it themselves.
Common Symptoms of a Bad PCV Valve
For your vehicle to emit the cleanest exhaust gases, it needs a fully functioning PCV valve. Unfortunately, PCV valves can break after a few years of use.
You must be able to recognize the symptoms of a bad PCV valve in your vehicle if you want to replace it with a new one. Most of these symptoms are not that difficult to recognize.
Be careful not to ignore these symptoms, or your engine may suffer irreparable damage. Here are the 5 most common signs that you have a bad PCV valve:
1) Oil leaks (burnt oil smell)
A functioning PCV valve works to reduce pressure in the crankcase. However, a faulty PCV valve can cause it to get stuck in the closed position. This can happen if the valve gets clogged or simply wears out over time.
Either way, this causes pressure to build up in the crankcase. High pressure increases the chance of an oil leak. This leak is most likely coming from a gasket or seal ring. It could also be oil in the intake manifold or throttle body.
A faulty PCV valve may cause oil to accumulate in the air filter. Although rare, oil may leak from the exhaust.
2) Check Engine Light
The engine control module is constantly in communication with the engine’s oxygen sensor. When the PCV valve fails, it usually results in excess fuel or air entering the engine’s combustion cylinders. This results in the check engine light on the dashboard.
You’ll need to use an OBD2 diagnostic tool to scan your vehicle to find any stored trouble codes. You may receive a code specific to the PCV valve, such as P052E or P053A, or a more general code, such as P0171 or P0174, when the PCV valve is only one of the causes of the code.
3) Engine Stall
The PCV valve has a piston that can get stuck open if it is defective. When this happens, it allows excess air into the combustion cylinder. This can cause the engine to stall or have a rough idle.
4) Poor fuel economy
Leaving the PCV valve closed creates an air-fuel rich mixture in the combustion cylinder. This means there is more fuel than air in the cylinder. More fuel usage leads to lower fuel economy and higher gas bills.
5) Engine oil sludge
These toxic gases escape into the cylinder walls and center of the piston during combustion and mix with the oil in the engine. When oil and exhaust gases mix together, sludge residue is created.
This sludge continues to build up and eventually damages your engine. You may not notice the sludge until you check your engine oil and notice the sludge itself. Engine sludge can cause noisy tappets and you may even hear a clicking noise in your engine.
How the PCV valve works
The PCV valve is a part that prevents these toxic gases from remaining in the engine block. The PCV valve is located inside the engine valve cover. There is a vacuum hose that connects the intake manifold to the PCV valve.
As exhaust gases enter the engine block, the PCV valve contains a spring-loaded piston that redirects the flow of gases from the crankcase to the intake manifold.
