Rep Power: 0

Hello,

On this 2015 Civic (almost 94k miles), I am getting a sound I can only describe as a whirling. Please listen to the attached video. The sound comes on at the 12 sec mark.

I ruled out a tensioner/pulley by removing the belt and turning the car on. Its still made the noise. Its hard to hear where the sound is coming from but its almost at the bottom of the engine... from what I can hear, around the bottom of the exhaust manifold.


Note: Not sure if its related but I noticed the sound after I removed the airbox to replace the air hose connecting the airbox to the throttle body. That's when I noticed it but the noise could have been there before or after I did the hose replacement.

Fix/Update - We discovered when removing either oil cap or dipstick it would stop noise. There was pressure building up. After replacing pcv valve and no luck, we removed the air hose we had previously installed and found that the crank case return port was not cut out from the factory. That’s what I get for buying part from Amazon. We drilled a hole to make an air way and problem was fixed, no more noise.

 
Rep Power: 366

long screwdriver works as a stethoscope

 
Rep Power: 221

Double check all the hoses are connected properly

 
Rep Power: 223

My first thought was a bearing in something belt driven (alternator, tensioner, power steering pump, water pump, A/C compressor). But if it still happens with the belt off, it rules that out.

Failing radiator fan that kicks on ~10 seconds after starting?