Vacuum problem in 06 XLT?

I recently bought an 06, 4.0, 55000.
Still under warranty from dealer and I took it back because whenever I step on the gas lightly, or when it shifts gears, I hear a hissing sound until I let off the gas or it shifts. I hear teh same sound when I turn the fan from defroster to "off". Are these normal? Related?

Also every once in a while, when traveling up a hill, I will lose air blowing out of the vents and it all blows out the defroster vents.

The dealer said there was nothing wrong after listening to it on a 5 minutes test drive. I know its probably not too serious, but its the whole idea. Dont tell me theres nothing wrong if there is actually something wrong, no matter how small.

p.s. I have been to hell and back with this dealer lying to me and breaking stuff when I put it in for service.

It sounds like you have a vacuum leak somewhere in the system. The reason that all the airflow goes to the defroster vents is because the vac is too weak to hold the vacuum motor that controls the airflow.

I would look for an open vac port on the intake manifold. Another possibility is that the vacuum reservoir is leaking or one of the lines that go between the vac reservior and the climate controls are leaking. I don't know where the vac reservior is on the 3rd Gen Explorer, so I can't help you there.

A good tech would use a hand held vac pump to test for leaks.

Just had another scare

Today I was driving, coming up to my road and I go to hit the brakes, and the pedal is a rock. I get it to slow down but still miss my turn. I turn around and the pedal is normal again.

So heres my question:
Is this related to the vacuum leak? Is the master cylinder controled by a vacuum line? Thanks

The brake booster is assisted by vacuum. So if your booster stops working, the pedal effort goes way up. You need to find the vacuum leak. It is possible that it may be the booster itself.

Any updates on this? I'm having the same problem with mine 2008 - V8 minus the air vents switching. I've took it into the dealer and they ended up calling the ford tech hotline. They've heard of 2 other instances but insist this is normal operation and to try an identical explorer w/ V8 since the vacuum systems are a little different with the 6/8 engines. They don't have any on the lot so I'm just gonna take it to another dealer.This is the second time they've tried to fix it so I will be taking it back in a few days to another dealer.

Update

I took it to the dealer....which is a horrible one....and they did a ride-along and said it was nothing and they refuse to fix it. So I dont know what now. But the hissing sound has changed a little...it now seems like its furthur under the dash...so i dont know.

dothedeww said:

I took it to the dealer....which is a horrible one....and they did a ride-along and said it was nothing and they refuse to fix it. So I dont know what now. But the hissing sound has changed a little...it now seems like its furthur under the dash...so i dont know.

Click to expand...

Well that sucks, kinda makes me wonder what they would say if the job wasn't under warranty, you'd think they would want to fix it for the $$$. They replaced the vacuum canister purge valve on mine this time and no luck. The first time a check valve on the vacuum intake side was replaced which solved it for about 3 weeks and now it's doing it again. So I guess it back to the dealer and let them deal with it, least the other dealer normally has a V8 they can compare it to, so we'll see.....

dothedeww said:

I took it to the dealer....which is a horrible one....and they did a ride-along and said it was nothing and they refuse to fix it. So I dont know what now. But the hissing sound has changed a little...it now seems like its furthur under the dash...so i dont know.

Click to expand...

I would either find another dealer or start calling Ford Customer Service (you should find phone numbers in your warrenty book) or both. I would make sure that Ford Customer Service knows that you lost the brake booster assist at least once (safety issue). As a last result, find a good independent shop to find the vacuum leak - it could be a safety issue if you lose the vacuum assist for the brakes.

Good luck.

see the problem I'm fighting now is that I bought the X used. So the manufacters warranty is no longer valid. But this dealer has screwed so much up that it should have been fixed when I bought it. I mean paying for an 06 should be somewhat fixed. They sold it with a bad parking brake, bad rear axle seal, clogged fuel filter, blown fuses, blown tailights. Plus they sold it uninspected (requirement in MD). I just found out last week they put the wrong leanholder on my title. I took it in for an oil change (free for life), and they busted one of my off-road lights off the front and tried to tell me it was there when they got it. (I took pix when I got to the dealership)

Everythings messed up with them and I just want this thing driveable. I drive 40 miles (each way) to school everyday and another 20 (each way) to work. Can't have something breaking down on me all the time.

dothedeww said:

I took it in for an oil change (free for life), and they busted one of my off-road lights off the front and tried to tell me it was there when they got it.

Click to expand...

Sometimes free isn't worth it. I wouldn't go back to a dealer that was screwing up my vehicle. Either try to fix it yourself, or find someone you can trust.

Got mine fixed, here's what they replaced:

YG 360 :Valve - Air Conditioner Contro

It was actually the diaphram in the valve that was bad.

Found the part, it's only $7 worth a shot to fix it your self

http://autoparts.cardomain.com/auto-part/794123-motorcraft-yg360-vacuum-checking-switch