Climate control - vacuum reservoir

[07EddyB]

Having a little issue with my climate control - everything works just fine but I'm getting a vacuum leak from under the dash when I load the engine. In neutral, I can rev the engine and no sound. Going down the road, when I give it gas I get a hiss. Was looking this morning and I noticed that my vacuum reservoir hisses when I shut the ex off. I suspect my other sound is coming from here also but I'm waiting for the wife to get home to take me for a ride so I can investigate. In the meantime, is my ex supposed to hiss when I shut it down? It may have always done it - maybe I just now noticed because I'm looking for a problem?

 

[07EddyB]

So the sound is definitely coming from the reservoir. After some more searching on here and looking at some parts diagrams I believe it is a check valve. Problem is I can't find it. Had to pop in to work for awhile - going back out now to try to track it down.

 

[07EddyB]

Found the check valve inline with the vacuum line under the hood. Pulled it out and was able to suck air through the wrong direction. Kept playing with it and it starting working correctly. Put it back in and test drove. No hissing on acceleration, no hissing on shut down. Working perfectly now. Moral of the story is that if you don't mind getting your lips dirty you can possibly fix the check valve by giving it a little exercise.

 

[Markaprice73]

Thank you. Just did this on my Father's 07 Sport Trac. Was hissing on acceleration. Disconnected it. Blew in and out on the valve a few times. Put it back. No more hissing on accel or shut down. Hopefully lasts. If not, it's a chap part. Thanks again

 

[Ornery]

Pretty kinky. Here's a PG rated image of the culprit:

 

[07EddyB]

I'm reviving this because my temporary fix finally stopped working. Be aware that if you try to go with the cheap option (the Help or Dorman generic check valve) it will not fit. The connections are too small and do not fit the vacuum hoses so don't waste your time or money. I finally ordered the Motorcraft part from Amazon for about $10 - dealer wanted $20 and didn't have in stock.

 

[Boomyal]

I'm reviving this because my temporary fix finally stopped working. Be aware that if you try to go with the cheap option (the Help or Dorman generic check valve) it will not fit. The connections are too small and do not fit the vacuum hoses so don't waste your time or money. I finally ordered the Motorcraft part from Amazon for about $10 - dealer wanted $20 and didn't have in stock.

Thanks for the heads up. I hate it when you order a generic, supposed, replacement part and you would have to mickey mouse things to make them work/fit!

I don't have an issue at this time but I will save this link, just in case.

 

[mvallyman]

I bought the doorman one, its not a replacement for the ford valve, its just a generic check valve.
The nipples are different diameters, on the smaller nipple 2 wraps of scotch tape made it fit tight into the vacuum line, working fine for 3 months now.

 

[banditxp]

Hate digging up old stuff but this seems to be the only thread about this and im having the same problem. I just cant find where that check valve is. Does anyone have a pic or can tell me where abouts to look? The hissing is driving me nuts lol. and always having heat blast me in my face sucks too.

 

[Old Irony]

Pretty kinky. Here's a PG rated image of the culprit:

What year is this one? My 97 doesn't seem to have it under hood. Someone said it's behind the glove box. It doesn't hiss but my toes freeze with the a/c on. Any ideas?

 

[94Eddie]

What year is this one? My 97 doesn't seem to have it under hood. Someone said it's behind the glove box. It doesn't hiss but my toes freeze with the a/c on. Any ideas?

The photo is of a 4th gen Explorer which is likely different from a 2nd gen Explorer/Mountaineer.

 

[Old Irony]

The photo is of a 4th gen Explorer which is likely different from a 2nd gen Explorer/Mountaineer.

I absolutely get that. Mine is actually a 96 1/2, some parts are 96 explorer, gas cap is one.