I can hear a hissing noise coming from the right front corner of the dash as the A/C is cycling. It is a cycling hissing noise and is more pronounced at high RPM or highway speed. The noise is louder than a comfortable radio level.

The noise started after the heat plenum was replaced. I took it back to the garage and they now tell me this is a normal sound for all 2011 models. I tell them the noise was never there before they worked on it.

Does anyone else hear this hissing noise?

 

Sorry, this is not normal. It probably an expansion valve that's gone by the wayside; this was a problem with the older therm expansion valves. It's odd that the orifice tube system was pretty well perfected, so it was changed to the more troublesome expansion valve system.
There could be something else going on, but does the A/C work normally otherwise? Noise concerns were very common on the expansion valve system, which was used in the rear A/C of the xpedition, xplorer, and windstars.
They should be able to fix this.

 

Hi this 2011 f 350 is using the old expansion vale idea that is electrically operated as to evap temp is this correct
the dealership will not look at this again because they say it is normal DO I just go to another ford dealership and jive them a try ?

 

OK, let's make this really fair for everyone. Go to the original dealer, and tell them you wish to compare (in your presence) your truck to another like unit (it shouldn't be that hard to find another truck very close to yours at a Ford dealer).
If they balk at this, tell them to screw off and go somewhere else.
It's worth remembering that you are (to the dealer) the customer. I realize that sometimes, as a tech, I can't make something that may or maynot have a problem different for the customer, but at the VERY LEAST, you can have the questions you have settled about this. If it's a very similar noise, then you'll have to live with it. If not, then something should be done.
I'm not known for my sparkling customer service skills, which is why I chose to work on things, rather then with people, but this really burns my *** when someone is told something without even their input. You obviously have a concern, and it may or may not be normal. These mechanical expansion valves do have a certain inherient noise that is normal. But, at the same time, you shouldn't have to blow the speakers out of the stereo system to get rid of it.
This is a classic customer service problem, and I'm really sorry if a lazy service writer doesn't want to get up and help you with this. That's why they call it work. You don't have to like it, just do it.
As a tech, I DO realize that you pay my paycheck (when Ford warranty isn't). And as a tech, I have to fix my problems. That's how I learn things. If it's NOT normal as compared to another unit, tell them to fix it until it is. That's callled customer service.
Please let me know. I'll keep an eye on this.

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