5 Symptoms of a Bad Oil Control Valve (VVT Solenoid)
The oil control valve (also called the VVT solenoid valve) is a critical component in variable valve timing (VVT) vehicles. The system is designed to control engine performance using two methods: retarding and advancing the camshaft angle. A bad oil control valve can spell disaster. To understand the oil control valve, you first need to understand how variable valve timing works.
The camshaft controls the timing of the intake and exhaust valves. In a dual overhead camshaft engine, there is usually one intake camshaft and one exhaust camshaft per cylinder bank. These camshafts are synchronized with the crankshaft via a timing belt or chain.
In a VVT engine, the camshafts can move independently of the rest of the timing system, allowing the valve lift to be advanced or retarded. This system goes by various names depending on the vehicle brand, but examples include Audi’s Valvelift, Ford’s FCT, Mitsubishi’s MIVEC, Honda and Acura’s i-VTEC/VTEC, Subaru’s AVLS/AVCS, and Toyota’s VVT-i.
The camshafts are adjusted by oil flowing through the VVT solenoid valve and/or oil control valve.
In general, the oil control valve serves several important functions. These include saving fuel consumption, reducing the exhaust gases produced by the vehicle, and improving engine performance.
Below, we will discuss some common symptoms of a bad oil control valve so that you can better diagnose if this component is the cause of your variable valve timing engine problems. Below are the symptoms of a faulty oil control valve.
1) Poor fuel economy (high fuel consumption)
As mentioned earlier, one of the main purposes of variable valve timing is to ensure that the valves open and close at the correct time to improve engine performance and reduce fuel consumption.
If the VVT solenoid stops working, the entire system is at risk and the intake and exhaust valves may open and close at the wrong time. This can result in a significant reduction in the number of miles per gallon of fuel.
2) Rough engine idle
Next, you need to consider the VVT system in your vehicle. This system automatically engages when your car’s RPMs are higher than normal or when additional power is needed, such as when driving. B. When passing another vehicle on a hill.
A faulty VVT solenoid valve in your vehicle can cause the engine to idle rough. Fluctuating engine RPMs directly translate to poor vehicle performance. While there are many other causes of rough idling, a faulty oil control valve is one to consider in vehicles with VVT technology.
3) Check Engine Light
Like the failure of other electronic components in the engine, your vehicle’s computer can detect a fault in the oil control valve and illuminate the check engine light in the instrument cluster. Using a diagnostic scanner can help determine if this part is the cause of the problem or something else entirely.
4) Poor Engine Performance (Frustrated Driver)
VVT can produce more power or save more fuel depending on the phasing of the camshaft. If the VVT solenoid has issues due to a faulty oil control valve, engine performance may suffer as the VVT system may not be able to optimize the engine for peak power.
5) Engine Knocking or Misfiring
Engine knock, also known as pre-ignition, is a phenomenon that occurs when gasoline burns before the spark plug ignites the mixture. Because this ignition occurs earlier than the ECU plans, this combustion cycle can waste fuel and reduce engine performance. If the knocking is severe, it can even cause engine damage.
What Causes an Oil Control Valve to Break?
The primary cause of a bad VVT solenoid is almost always oil. In most cases, old oil is the culprit. As oil flows through your engine, over time heat and tiny contaminants combine to thicken the oil. If this goes on long enough before an oil change, the engine oil’s consistency will be comparable to sludge.
It’s so thick that it can no longer get through the valves, literally clogging them and causing the valves to fail. This is another reason why regular oil changes are so important. Additionally, if the engine oil level gets too low, the oil control valve can fail.
There are some high-quality oil additives available that will help clean clogged oil passages.