I have a 2019 Q50 Hybrid, with 15,500 miles, I am the second owner. I have noticed that when you are moving forward, for example, on a street and you stop accelerating (that is, the car continues moving forward without accelerating), it generally turns off and shows the EV, and when you accelerate again to continue moving forward, you hear a squeaking noise (as if some metal were missing oil). This happens when it switches from EV to Gasoline and it turns on. At first I thought it was the vehicle's ignition, but it doesn't do this when the car is stopped, for example in park or when you shift into reverse or drive. I thought it could be the electric motor, but when you are in park and it shifts between EV and Gasoline, you can't hear it. It only moves forward. I think it's something related to the transmission. Has this happened to anyone? What could it be?
Hello,
This is a very specific and interesting issue with the Infiniti Q50 Hybrid system. What you're describing—a squeaking noise when the gasoline engine turns back on while the car is already in motion—is a known characteristic of the Q50 Hybrid's powertrain.
Your suspicion that it's related to the transition between the electric motor and the gasoline engine is likely correct. The heart of the Q50 Hybrid system is a two-clutch system. There is a "dry clutch" located between the engine and the electric motor. Its job is to engage and disengage the gasoline engine from the rest of the drivetrain.
Here's why you're hearing that noise:
- When you are "coasting" (moving forward without accelerating), the gasoline engine is shut off and the dry clutch is disengaged. The car is being powered solely by the electric motor.
- When you press the accelerator again, the system needs to re-engage the gasoline engine to provide power. The dry clutch must quickly re-engage to connect the engine to the electric motor and transmission.
The squeaking or rattling noise you hear is often caused by the clutch's engagement. It's similar to the sound of a manual transmission's clutch being engaged, but in your case, it's an automated process.
Possible Causes:
- Dry Clutch Noise: A light squeak or groan during this transition is not uncommon. It's a symptom of the clutch plates engaging, and it can become more noticeable over time, especially if the clutch plates are wearing down or if there's an issue with the clutch actuator. The fact that it doesn't happen when the car is in Park is a key clue, as there is no mechanical load on the transmission or clutch in that scenario.
- Engine Mounts: Less likely, but still possible, are worn or failed engine mounts. If the mounts are weak, the sudden torque of the gasoline engine re-engaging could cause a slight metal-on-metal noise or squeak as the engine shifts its position slightly. However, this would typically sound more like a clunk or a creak.
- Accessory Belt/Pulley: It's also possible, though less common for this specific symptom, that an accessory belt or a pulley on the engine is slightly worn and is making the noise. When the engine is off (in EV mode), these are not spinning, but when the engine turns on, they all start up, and a worn belt or bearing could squeak under the sudden load.
What to Do:
Unfortunately, since the dry clutch is a critical and complex part of the hybrid system, this is not something you can easily diagnose or fix yourself.
- Take a video:** Try to safely get a video of the noise. Capturing the sound on video will be extremely helpful for a mechanic to properly diagnose the issue.
- Schedule a professional inspection:** The best course of action is to take your Q50 Hybrid to a reputable Infiniti or Nissan dealership. A qualified technician will be able to perform a more advanced diagnosis and pinpoint the exact source of the noise. They have the specialized tools and knowledge for these complex hybrid systems.
It's good that you've been so observant and that you can reproduce the problem. That's the first and most important step in getting it fixed. I would not ignore this, as a failing dry clutch or actuator could lead to bigger, more expensive problems down the road.
