hissing noise in vacuum reservoir

[stevewinston]

I had been hearing a hissing noise any time I accelerated. I discovered the sound was coming from the vacuum reservoir tank located under the glove box. Is anyone familiar with this issue? Will replacing the reservoir fix the issue? I made sure the T connector with the hose was secured properly. I'm not even sure what the vacuum reservoir tank does if anyone can clarify.

 

[daspud]

I have the same issue , hope someone has some input.

 

[bender]

i had the same problem, dealer replaced the HVAC controller (not official name, i will have to look at the paperwork to get the name) but i believe it was a "vacuum manifold" no more noise.

 

[mjktg99]

i had the same problem, dealer replaced the HVAC controller (not official name, i will have to look at the paperwork to get the name) but i believe it was a "vacuum manifold" no more noise.

If you could post exactly what your dealer replaced that would be great! Mine tried telling me it was normal. I would like to go in with more information so I can try and force their hand.

 

[geoffj981]

Anyone else have any idea what part bender is referring to? I have the same issue and would like to try and get it fixed.

 

[08Mountaineer]

Anyone else have any idea what part bender is referring to? I have the same issue and would like to try and get it fixed.

I would also like to know this my Mountaineer sounds almost like it has a turbo with this same hissing noise lol

 

[geoffj981]

There's a part called a A/C Control Module; Check Valve. It looks like it may connect to the reservoir somehow. I wonder if this is the part?

 

[bender]

Sorry I was traveling, I will look at the paperwork tonight and post the part.

 

[geoffj981]

Still no reply?

 

[geoffj981]

Well, in this thread http://www.explorerforum.com/forums/showthread.php?t=234029&highlight=vacuum+reservoir the person was having the same issue. i replaced the check valve piece and I'm still hearing the hissing. It's crazy because I thought for sure it would fix it. I wonder if I should try replacing the reservoir or putting some epoxy around the seam.

 

[CCMPower]

hissing noise behind glove box....

I am having the same issue with my 2004 Explorer. I know for a fact the hissing noise during acceleration and when I shut if off is coming from that oval shaped vacuum tank. I was under the impression there is a valve in that tank but now i dont think that's the case. I think the problem you guys have as well as me is either the tank itself(which I dont seem to see any leaks on) or some type of A/C vacuum check valve that hooks up to it via a vacuum line. The dealership has a part# for both of these items. Im not sure what will fix this problem at this point in time though.

 

[geoffj981]

CCMPower, you are right. There is a check valve that connects to on of the hoses. If you follow the hoses through the firewall you will see it connect to the valve. I replaced the valve but I still hear the noise. It may be worth a shot for you to replace it. You can go to http://www.fordparts.com/ it's part number 19A563 A/C Control Module check valve.

 

[CCMPower]

CCMPower, you are right. There is a check valve that connects to on of the hoses. If you follow the hoses through the firewall you will see it connect to the valve. I replaced the valve but I still hear the noise. It may be worth a shot for you to replace it. You can go to http://www.fordparts.com/ it's part number 19A563 A/C Control Module check valve.

Hey Geoff, thanks for the response. I saw this subject on the forum and figured I'd jump in and see if I could help out in the conversation as well since apparently Im not the only one with this annoying problem. Do you happen to know what the a/c check valve looks like? I already knew the part number but thanks for reminding me what it was. I think the Ford dealers sell it for $12 but that little tank itself is like $109...........a total ripoff on that piece. I figure the tank is just that...........A TANK! I found no leaks on it so the source of the hissing must be coming from somewhere else. Maybe your tank actually has a leak since you already replaced the valve with no luck. Any ideas on your situation?

 

[geoffj981]

The check valve is a small plastic piece. Mine is half black half white. It's circular in the middle with a stem on both ends where the hoses connect. it looks similar to this image.

.

I'm going to try and put some epoxy around the seam of the tank but I think the leak may be coming from somewhere else.

 

[CCMPower]

Let me know how the epoxy works for you. Im hoping that solves your problem. I checked out my tank and everything behind that glove box pretty in depth and everything is in order. No leaks on the lines and everything is pretty tight and secure in there. Im going with the valve replacement to see if that will solve it for me.

 

[CCMPower]

Hey Geoff, I picked up that A/C vacuum check valve yesterday for $11 and put it on. Problem solved! It's back to normal again. Just out of curiosity, when you put that valve on your Explorer did you put it on with the white part of it facing the firewall? I noticed that was the way it goes on and I'm wondering if you reversed it and maybe thats why yours is still making the hissing noise? It seems like the only two things that could cause that noise are either that valve or the vacuum tank leaking. I guess the other option for you is to epoxy the tank but they seem like they are put together decent that they shouldn't have cracks in them. Mine looked pretty good when I pulled it out. Let me know how it goes.

 

[xTOM153x]

The check valve is a small plastic piece. Mine is half black half white. It's circular in the middle with a stem on both ends where the hoses connect. it looks similar to this image.

.

I'm going to try and put some epoxy around the seam of the tank but I think the leak may be coming from somewhere else.

hey just wondering did you ever fix the hissing noise and where exactly is this valve located under the dash i ordered the part today hoping it will solve my problem when i put it on

 

[CCMPower]

Good morning Tom. That A/C check valve is actully located in the engine compartment. The vacuum tank behind the glove box has two hoses coming out of it and they go through the firewall. They come out on the passenger side in the engine compartment. You should be able to spot it almost right away from the pictures that are posted on here. One of the hoses will connect to this valve and then to another hose that goes up toward the front of the engine. The two hoses are pretty easy to pull off of this valve and then just plug the new valve back in where the old one was. It's a real easy fix. I put mine in about a month and a half ago and it worked great. No more hissing noise! If you need anything else, let me know!

 

[CCMPower]

Good morning Tom. That A/C check valve is actully located in the engine compartment. The vacuum tank behind the glove box has two hoses coming out of it and they go through the firewall. They come out on the passenger side in the engine compartment. You should be able to spot it almost right away from the pictures that are posted on here. One of the hoses will connect to this valve and then to another hose that goes up toward the front of the engine. The two hoses are pretty easy to pull off of this valve and then just plug the new valve back in where the old one was. It's a real easy fix. I put mine in about a month and a half ago and it worked great. No more hissing noise! If you need anything else, let me know!

One other side note to this. I first heard this hissing noise back in January of '08. My Explorer was still under warranty at that point so I figured I'd just take it in to the dealership and let them deal with it. The tech manager called me later that day and said they couldn't figure out what was making the noise. He said they did a compression check on everything and found nothing. The funny thing was I picked it up later that day and the hissing was gone. To this day, I dont know if it happened to stop on it's own or they did something to it not knowing they had "temporarily" fixed it. I just think its kind of odd that a Ford dealership can't seem to find the source of this problem when there are people on this forum who can tell you exactly what it is. If you guys ever have a problem definitely come on here first because there is a very good chance you'll get some good info to help you with your problems rather than pay a garage or a dealership big bucks to tell you they have no idea how to fix your vehicle or they just charge you for a mess of parts they throw at a problem HOPING it'll fix the problem.

 

[stevewinston]

Mine is still hissing. I've replaced the check valve and it didn't fix the noise. The tank seems to be fine, no cracks. Not sure what else to try.