The last few days when I start my truck, about 15 sec after start-up I would hear a pop in the passenger fender well area.
I removed the passenger wheel and inner fender well. Started the truck and went to check the rservoir (black box mouted in fender well with vacuum lines going to it),,,,,I assume that's the reservoir........That's where the pop is coming from, just once when the vacuum builds up.
It's a sealed unit, so I guess I should just replace it.....Any ideas or advice would be appreciated....And someplace online to check out prices, etc....


thanks guys, Toby

 

HI!... Do you means this?

https://www.f150online.com/galleries...-793-15769.jpg

This is a vacuum resevoir for your climate controls (HEATER, A/C, DEFROST etc.) It stores vacuum so you still have use of the controls when the vehicle is off. IMO why would you want to use your climate controls when the vehicles not on? You won't get heat or A/C. I found this vacuum tanl useless and removed it about 4 months ago. No ill effects. Just make sure you re-connect the two vacuum line going in and coming out of the tank together or you won't have ANY use of your climate controls. Hope this helps you out. If it does have a crack in it, just remove it, why waste your money on a new one.

 

what i'm talking about is on the other side, i had to remove the passenger side tire, then the plastic splash gaurd(wheel well) it mounts up inside the fender. It's mounted with 2 bolts, is kinda long, like formed to the shape of the fender, has two vacuum connections(2 lines on each one)the lines right there by the computer harness go to it. If you look down where you would change the passenger side headlight bulb, you can see it in there. It may be the same as you say, they could have changed it, you know Ford...lol

OK, I did some research.....this vacuum reservoir is for emissions. It's got 2 chambers to it...the small chamber(not popping)goes to vapor management valve.
the large chamber(popping) goes to the DPFE sensor and EVR solenoid.

It seems to hold a vacuum ok, but it pops loud, it's annoying................guess i'll just replace it..Maybe some good info if this happens to anyone else.

 

That canister is there for you to maintain your HVAC controls when your driving. If you have no ill effects from removing it, then you have a working check valve somwhere. THe resovoir is sort of a failsafe, if that check valve quits working the resorvoir may hold enough vacuum to keep everything working. Also, you may notice that when you are acelerating, especially in OD, you may lose your ac and it will come thru the defroster ducts. When you accel your engine vacuum drop significantly. The resovoir is just supposed to hold you over till your engine vacuum resumes.

 

The one Neal has pictured is for HVAC controls, the one I have pictured is for emissions. The one for HVAC controls is inside the engine compartment(behund the battery), the one for emissions is inside the fender(you have to remove the plastic splash gaurd in the whell well), not in the engine compartment.

 

HI!... I think the newer trucks have it in a different location than your "97". My truck does'nt have any sort of emissions resevoir in either fender well area. I've had my fenders and inner fender wells out several times (installing headers/replacment of fender it'self) and have never seem what you have pictured. My 99" does have another vaccum resevoir at the back of the truck mounted to one of the frame cross members under the box. I beleive that is where my emissions resevoir is located.

 

do you have a heat gun. try to put press on it. and find where it pop's. then apply a little heat. and just slightly deform it alittle. be careful. it is plastic. its like a tin can affect. before you reinstall. hook it up and try it. you should not hurt it. do not remove it. it does help hold vac under heavy load. i have seen this before. no big deal. have not tryed this repair yet. but i'll bet it work's. its just plastic. good luck.

 

Wino, we must think alike. Yesterday I put some pressure on the spot it was popping at with a c-clamp vice grip, heated it up, and let it sit for a while. Removed the clamp, hooked it up and no pop.

 

Hi ,i thought mine was the only one,how has the heating up thing worked out ,does replacing it make a difference or is it from to much pressure,where exactly on it was it that yours is popping ,i can hear it popping but cant see it,it sounds like it is comming from inside it , any help would be appreciated,please let me know
at JPatterson@telus.net

 

That was quite a while ago. But it still doesn't pop anymore. I can't recall where exactly I clamped/heated it. I removed it from the truck, pushed on it in spots till I found the popping spot. Put a vice C-clamp on it, heated it a bit, let it sit for a while clamped. Fixed it right up.

Must be somthing in there that comes apart after a while of cycling vaccum. You'll be able to find the spot after you remove it. It's like one of those clicker toys.