hissing sound

[theeaterofshades]

Started hearing a hiss/"shhh" sound coming from what sounded like the passenger side everytime I pushed the accelerator with light to medium pressure today. The more I press on the pedal, the louder it became until enough pressure was applied and the sound went away. It is loud enough to hear over talk radio but I could not hear it with music playing. My explorer is a 2007 XLT with just over 80,000 miles.

 

[Ornery]

I'm going to guess it's a vacuum leak in the climate control. Try changing the settings on the heater and A/C to see if it goes away. Might help track down the location a little bit. In the end, somebody will have to sift through the plumbing behind the dash.

 

[The Scott]

Search it and you should find info and the PN you need. There is a plastic diaphragm near the passenger side firewall in the engine bay that you swap out. The part from ford is about $7 if I remember correctly. I had to do this a few months back.

 

[07EddyB]

I had the same problem - look here http://www.explorerforum.com/forums/showthread.php?t=371087

 

[Old As Dirt]

When my 2007 XLT started hissing, I dropped the glove compartment (press in the sides and let it swing down) and found multiple vacuum lines in the top left of the area that was exposed. While none of them looked like they were about to fall off their connectors, I twisted and tightened them all. While I did not feel that I had changed anything, the hissing stopped and has not started back after 3-4 months.

 

[Ornery]

hissing noise in vacuum reservoir - stevewinston 01-23-2010, 07:04 PM

19A563 A/C Vacuum Check Valve

 

[rusty813]

i have this problem as well...if someone can post a picture of where its located, that would be cool

thanks,
rusty813

 

[Ornery]

I'm assuming you hear the hissing from resonance in the reservoir behind the glove box:

That, or there's actually a leak in the reservoir, or nearby vacuum lines or connections.

 

[theeaterofshades]

Thanks! $14.00 for the part, 3 minutes to locate and change, and all is well. The pics were especially helpful in locating it. I appreciate the help!