Q: I have a 2010 Toyota Highlander and it’s making a rattling sound under the hood. It’s louder when idle. What could this be?
Rattling noise under hood. It’s louder when idle.
My car has 100000 miles.
My car has an automatic transmission.
Recommended Services
| Car is making a noise Inspection | $94.99 - $114.99 | Get a Quote |
Louder at idle is a concern. At idle, oil pressure is at its lowest which particularly impacts the valve train. If the issue is not "within" the engine, other possibilities are the circuit of accessories that are driven by the serpentine belt. That "collection" is ruled in or out by disconnecting the serpentine belt and running the engine for a few SECONDS. If the noise disappears, obviously the source of the noise is sought from amongst that collection of components. If you request a vehicle noise diagnostic, the responding certified mechanic will pinpoint the origin of the noise and get this issue taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
The statements expressed above are only for informational purposes and should be independently verified. Please see our
terms of service
for more details
Get an instant quote for your car
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing
What others are asking
How do I deactivate the BeltAlert seat belt reminder?
The BeltAlert seat belt reminder alerts you when the driver or front seat passenger does not have their seat belt on. The seat belt reminder detects whether there is a person in the passenger seat, and reminds them to put...
Whistling sound coming from front of car while driving.
This sounds like a possible bad wheel bearing. I would enlist the help of a YourMechanic professional to check your wheel bearings with an automotive stethoscope. This will help the professional to determine where the noise is coming from. (https://www.yourmechanic.com/services/car-is-making-a-noise-inspection)...
Power steering stops working at low speeds
The slower the vehicle is moving, the harder the power steering system has to work. So if the power assist is failing at slower speeds, the more common issue is either a faulty pump or a serpentine belt that is...
Transmission issues, rough shifting and noise
Many different faults can cause the vehicle to shift roughly. The most common would be low fluid level (https://www.yourmechanic.com/services/transmission-fluid-service) in the transmission, transmission mounts, the torque converter, or one of the shift solenoids (https://www.yourmechanic.com/services/downshift-solenoid-replacement). If you'd like to get this...
Having trouble with trouble code P0455.
Hi. Trouble code P0455 (https://www.yourmechanic.com/article/p0455-obd-ii-trouble-code-system-gross-leak-evaporative-emission-by-john-nelson) is for the emissions system of the car and the only effect it will have on the car is the fuel economy may go down slightly and the car will pollute the air a little...
Transmission P0932 error code in fiat bravo 120 tjet
This is a code related to the hydraulic pressure sensor in the transmission. As you may know, automatic transmissions use pressurized hydraulic fluid to change gears. Every time a gear change is required, the car's computer activates a transmission solenoid,...
Is my tire & mag salvageable?
It's not a great idea to run on a flat tire but if you are talking about only literally 100 meters, it is possible the tire is OK. The reason it is newly leaking from the tire bead area is...
My car stalls with weather under 40' or moist out.
Hi there. There could be two things that are contributing to your issues with the vehicle that are playing a big roll in this. First check the manifold absolute pressure sensor (MAP (https://www.yourmechanic.com/services/manifold-absolute-pressure-sensor-map-sensor-replacement)) on the engine. Check to see if...
Transmission was replaced but not set in right so it won't bolt down believe it's disk between motor and transmission
The problem sounds like the transmission torque convertor is not inserted all the way into the transmission. If you try and force it you will damage the transmission. You need to spin and push in the torque convertor until it...
Related articles
Top 10 PZEV Cars for Eco-Friendly Drivers
Teddy Leung / Shutterstock.com The whole idea of a PZEV (that is, a partial zero-emissions vehicle), seems paradoxical. You’d think it’d have to either be zero-emissions or not in the category at all. But as contradictory as...
How to Turn Off the Reverse Beep in a Prius
The The Toyota Prius is designed to shut off the engine when stopped as an energy-conserving measure. When the accelerator is depressed, it starts to back up, so you can go about your business on the road. When your Prius...
How to Use an iPod in a Toyota Prius
Gone Gone are the days of toting around cassette tapes or CDs in cases to keep tunes on hand when you're on the go. Today, we have playlists on our portable devices like iPods. When you don't have the latest...
Browse other content
Maintenance
Services