Strange "tuning fork" LOUD sound when sitting still or just taking off….

[UKHOOPZ]

I have a new 2015 Limited that I got 3 months ago. For about 2 months I have been hearing a strange sound that sounds like a tuning fork. It over powers the radio….it is quite loud. It never happens at highway speed, but can occur either when I am sitting still or when I am accelerating from a dead stop. I am unable to really tell when it is coming from for sure, but I "think" it is coming from the rear passenger side, but cannot be sure. It fills the cabin with sound and is difficult to pinpoint. It usually last only a second or so but occasionally will last for several seconds. Sometimes, I am sitting at a red-light and it starts "singing". It can be quite embarrassing! Obviously, I am calling my ford dealer soon, but I was wondering if anyone had any ideas what it might be so I could help them find my problem. Thanks so much!

 

[peterk9]

Coil spring?

Peter

 

[UKHOOPZ]

Coil spring?

Peter

Sometimes, I am just sitting at a red-light and after a few seconds of sitting perfectly still it starts that whiny tuning fork tone. It is very loud! It will last for 5-6 seconds and go away. Would a Coil Spring do that?

 

[peterk9]

Sometimes, I am just sitting at a red-light and after a few seconds of sitting perfectly still it starts that whiny tuning fork tone. It is very loud! It will last for 5-6 seconds and go away. Would a Coil Spring do that?

No I don't think it would. I thought perhaps it may have shifted and popped back into place, if that is even possible, thereby causing a reverberating noise. I don't recall any other post here with your particular description of the problem. If it does it while sitting in 'Park', try opening the hood while the engine is idling to see if you can get a better idea of where the noise is coming from. Something that is intermittent can be a very difficult and time consuming thing to track down. It may help the techs if there is a way you can get a recording of it when it occurs if that is possible.
Good luck and let us know what, if anything, the dealer finds out.

Peter

 

[UKHOOPZ]

Sitting still….

Today, I was sitting still in the driveway waiting for my son and my Explorer was idling and the transmission was in park. The sound started up and stayed for a few seconds. I jumped out of the car and jumped underneath the rear quickly enough to determine that it is indeed coming from the rear of the vehicle. I cannot tell exactly where it is coming from, but it seems to be coming from the center of the rear-end axle area….though that could be wrong. The sound stopped about the time I got back there. It is loud enough that you would hear it if you were 20 yards away….easy. What in the heck could cause such a sound when I am not even moving? The transmission can be in park or drive, and it NEVER happens at highway speed. The fastest I've been when it happens is probably less than 20 mph. Any ideas?

 

[peterk9]

If you are in Park, then nothing that I know of should be moving. I'm wondering if it could possible be the fuel pump? I believe it sits on the top of the tank.

Peter

 

[Halwg]

If you are in Park, then nothing that I know of should be moving. I'm wondering if it could possible be the fuel pump? I believe it sits on the top of the tank.

Peter

My 2008 made a noise like that and it was a valve body in the transmission. Required a transmission rebuild.

On noises underneath the car, it's hard to tell where they are exactly as the sound reverberates through out the underside.

But as Peter says, it could also be a faulty fuel pump. It could be the AC compressor, it could be a ton of things and nobody on this forum can diagnose it from your description. It's going to take a mechanic seeing what the issue is.

 

[The_Bishop]

One of the vacuum lines from the fuel tank/evap system? Isn't that stuff in that area as well?

 

[UKHOOPZ]

I really appreciate all of your feedback. I will be sure to let you all know what the dealership comes up with.

 

[UKHOOPZ]

Well, it turns out that they think it is a bad Air Expansion Valve in the rear AC. They checked it last week and ordered a new one. They called today to let me know that the part has arrived. So, my explorer went in this afternoon to get that changed out. Hopefully, this will take care of the problem. Fingers crossed……..

 

[UKHOOPZ]

Well, so far they have gotten it right. I've been driving it now for about 3 days with NO SOUNDS coming from the car! I will update only if there is a problem. So, maybe it did turn out to be the rear Air Expansion valve! Thanks, Golden Circle Ford in Jackson, TN!!