I’m convinced my 02 honda civic does not like traffic nor hot weather. Whenever i’m in traffic for more than 20 minutes (which is about everyday) it starts to make this loud buzzing noise. Seems to be the way my car is telling me that it does not want to be in traffic. I can sure relate. Me neither. When the weather gets hot, my car does the same thing. Can you relate to my car as well?
Can you be a little more discriptive? Is it coming from underneath, in back, in front? Change with speed, engine speed, with brakes applied or off? Change depending on what gear you are in? Could be just a loose heat shield or something else.
The sound comes from the front of the engine. Its volume is in line with the rpm of the engine and is not dependent on the gear. So its the loudest during acceleration in higher rpm.
It could be as simple as a loose plastic cover over the top of the engine or a loose plastic splash shield under the front (just fixed one of those). Start by lifting the hood, having a friend rev the engine (with the parking brake on, the trannny in P, the wheels chocked, and your friend’s foot on the brake PLEASE), and listening for the sound. Odds are that its source will become obvious.
If it doesn’t, you can pick up a 'mechanic’s stethoscope" for typically about $10. That’ll help isolate the source.
NOTE: If it seems to be coming from a splash shield under the car, DO NOT get under an operating vehicle. Put the car securely up on ramps, engine off, and find it that way.
Could it be possible that the electric radiator fan is making noise? Might want to take a look at that as well, when the hoods up.
I think your car is trying to warn you, nice car that it is, something is going to go wrong really soon, get it checked. If you can replicate the problem for the shop the solution should be simple, though not necessarily inexpensive.
If it changes with RPM, than more than likely it is an accessory or cover as mentioned the “same mountainbike”. Being that it could be chased down with the car sitting still makes life much easier.
It may be trying to tell you to also change your timing belt and waterpump? Since car has 233k miles and has never even serviced? Who knows. Cars talk, right?