Ground wire-like sound when accelerating

[Harrisburhfordexplorer]

Hi everyone,

Just got my explorer last month. It's a 2010 xlt with 98k. I really like it but it's had some issues already. Few weeks ago the dealership replaced a wiring harness that had become corroded on the transmission. They didn't charge me which was nice but now I have a high pitch sound only when accelerating and the truck is moving. Sounds like a ground wire but occurs with or without the steroids turned on. Stranger thing still is that it only happens in the 2k rpm range...that I can hear. The sound appears to be comming from passenger side maybe by the wheel? Can't get it to sound when I have it in the driveway.

Anybody else deal with this? I'd like to try and take care of it myself if it's simple enough, if not I want to take it back in and be specific about the problem so I'm not without it for another week and a half.

Have a great day.

 

[07EddyB]

Well - I don't really know what a 'ground wire' sounds like or what steroids have to do with anything so I'll just address the fact that you are hearing a sound coming from the passenger footwell. I'm betting you hear this sound on the road when you accelerate with the engine under load but not in the driveway since the engine isn't under load. There is a vacuum reservoir for the climate control system located in the passenger footwell. In the engine compartment there is a check valve that is supposed to hold vacuum on this reservoir. When this check valve fails, the reservoir fails to hold vacuum when you need it the most - when the engine is under load and producing less vacuum - and it makes a very distinctive sound as the air rushes in past the failing check valve.
I know I'm taking a leap here but....

 

[Tech By Trade]

yep, that check valve is what comes to mind. Kind of a whistle like sound.

 

[Harrisburhfordexplorer]

yep, that check valve is what comes to mind. Kind of a whistle like sound.

Kinda like a whistle is there anything I can do to stop the noise?

 

[Tech By Trade]

Replace the check valve. Its only a couple bucks. Not sure about the part number though.

 

[Jacob Linder]

Funny, I've had that sound come up in the past few months. Now I know what I'm looking for

 

[07EddyB]

And get the Ford/Motorcraft part. The hose barbs are a different size on each side. A generic valve doesn't fit.
A quick check - locate the check valve - on the V8 it's close to the firewall on the passenger side in the engine compartment. Remove the valve and, well, put one end in your mouth and suck and blow gently. If it's stuck you'll know. If it is stuck you can usually free it by continuing to gently work it. Reinstall and see if that fixes your problem. I know that sounds gross but it works.

 

[Harrisburhfordexplorer]

Before I start ripping my explorer apart I just want to be clear about the sound, it's sounds similar to a turbo spooling but very high pitch. Is that comparable to what you've come across with the check valve?

 

[Tech By Trade]

Yep, and not much tearing apart. Its visible on the firewall from the under the hood. Easy fix and cheap.

Motocraft YG360, you will find it here http://www.explorerforum.com/forums/index.php?threads/2008-explorer-ac-issue.409640/

 

[07EddyB]

It would be nice if people would report back instead of the usual hit and run.

 

[Harrisburhfordexplorer]

It would be nice if people would report back instead of the usual hit and run.

Sorry for the delay. There are several check valves and I couldn't figure out which this would be related to and I'm not mechanical enough to figure it out on this vehicle so I took it to ther dealership, they diagnosed it as a hub bearing, thankfully I have the extended warranty. Drove it out and the sound was still there... apparently I also needed a hub bearing. When I came back in the following day they had a technician ride along to hear what I was hearing. I mentioned again a check valve and they dismissed it. Not sure exactly what was done they only told me there was a vaccum leak at the back of the engine. Thank you all who responded.