[dixierob]

Hey all. I’ve got a weird noise I’ve been trying to track down on my 2006 TJ 4.0L. I can only hear it when I’m in the carport at the house, and only after the engine has warmed up. Mostly I notice it when I come back to the house after a trip to the store or something. It’s a high-pitched noise. I originally thought it might be an oil pump or other belt-driven component going out, but after a little bit of troubleshooting, I don’t think it’s anything connected to a belt.

With the engine running, I poked around for a minute and found that it’s the loudest when I stick my ear up to the horn on the front of the airbox. Tried to isolate the problem by unclipping the airbox and opening it up to see if it was the filter making a weird seal or something—no help. It’s like the noise is coming from the other end of the air tube (throttle body or possibly a CCV / inlet hose).

Any ideas on how best to troubleshoot what’s making this whistling noise?

Thanks!

 

[Digger84]

Positive it is not OPDA?

 

[dixierob]

Positive it is not OPDA?

...unless I got the one ’06 that has its OPDA mounted inside the air cleaner...

 

[dixierob]

Any thoughts on pulling the main vacuum hose off the brake booster and hooking it up to the fog machine I got last Halloween?

 

[Digger84]

Could listen with air tube removed from throttle body

 

[dixierob]

Just ran to the store and back. Tried getting a video of the noise after. It's faint, but you can definitely hear the noise when I get over by the air intake. It's normally louder, but it's pretty cold out today and the engine hardly got heated up to op temp. Anybody recognize it?
http://youtu.be/jFWvZwS1aZs

 

[dixierob]

Digger, that's a good idea. I'll do that and post what happens.