My car started making a loud noise a few weeks ago, but only when through the parking garage at work after driving ~30 minutes. Then it made the noise on the way home sitting in traffic. I have no CEL's, and the car drives completely normally.

The noise can be described as a LOUD buzz/horn like sound coming from the engine bay. it only came on intermittently and at random times, not changing with speed, whether I was just stopped in traffic, etc. I really have no idea what would cause a sound like that, has anyone else encountered anything like this?

Any ideas would be great, it's at the shop right now but they haven't found anything so I'm going to have to try and locate it myself. Thanks in advance.

 

If air is in the power steering system, the power steering pump makes a buzzing type noise. But I wouldn't call this noise a horn type sound, though. The Nissan power steering does not use the stuff sold as "power steering fluid". It uses Dexon ATF. Power steering fluid will cause buzzing.

 

Alright thanks, well I told them to flush the power steering so hopefully the sound disappears. Can the ps pump get very loud? I mean, windows up and radio on I could still make out a noise.

 

it can get pretty loud.