After just driving back from a 100km mountain road trip, I opened the engine hood and heard a strange noise, like metal clashing or rubbing against each other. I recorded a video, please see below.
But strangely, it doesn’t seem directly related to the engine RPM. I tried turning off the engine and restarting it after a few minutes. At first, there was no noise, but after a few seconds, the sound started. It was very faint at first, but over the next ten seconds or so, the sound gradually became louder and the frequency increased. After reaching its peak, it persisted for several tens of seconds before suddenly disappearing. Then, I went out for another two to three kilometers, parked, and opened the engine hood again. I could hear the sound—it wasn’t very loud at first, but after a few seconds, it started getting louder and the frequency increased. It lasted for about twenty to thirty seconds before disappearing.
I initially suspected an issue inside the engine cylinder block, but after noticing that the sound would disappear, I began to wonder if it might be related to the high-pressure fuel pump? Because the faulty sound of the high-pressure fuel pump I found online sounds somewhat similar to the noise from my engine.
But strangely, it doesn’t seem directly related to the engine RPM. I tried turning off the engine and restarting it after a few minutes. At first, there was no noise, but after a few seconds, the sound started. It was very faint at first, but over the next ten seconds or so, the sound gradually became louder and the frequency increased. After reaching its peak, it persisted for several tens of seconds before suddenly disappearing. Then, I went out for another two to three kilometers, parked, and opened the engine hood again. I could hear the sound—it wasn’t very loud at first, but after a few seconds, it started getting louder and the frequency increased. It lasted for about twenty to thirty seconds before disappearing.
I initially suspected an issue inside the engine cylinder block, but after noticing that the sound would disappear, I began to wonder if it might be related to the high-pressure fuel pump? Because the faulty sound of the high-pressure fuel pump I found online sounds somewhat similar to the noise from my engine.
. It was the noise from the purge valve, when the mechanic unplug it, the noise disappear. I also tried yours, nothing changed when I stuck this hole, so it's not about the PCV valve.
