F250 A/C advice

[Shrimpngrits]

I recently had the evaporator coil replaced in my 2012 F250. I picked it up on Friday evening as they were closing and upon driving it home I noticed a hissing/sighing noise every 10 seconds. I made an appointment with them the following week to check it out. Upon doing so they’ve told me that the sound is air moving through the expansion plate every time the compressor kicks on and that the system is running fine and everything is great. They did state that the evaporator coil they used is an aftermarket one and while they’ve heard nothing like this happening before, it could be the reason.

I’m not a nit picky kind of fella but this noise is pretty annoying and I feel having paid the amount of money I’ve paid to get the work done that it doesn’t seem right for them to treat this as a nothing burger. Any advice?

 

[ilbcnu]

The only thing that should be moving through the system is refrigerant. Does it cool as it did before the changes?

 

[Shrimpngrits]

I’m sorry, I see now I used the word air instead of refrigerant. I only meant that it “sounds” like air hissing…

Yes it is cooling quite well; it went out back in October and I went as long as I could before my kids couldn’t take it anymore!

I don’t know enough about A/C systems to know if this is just an “audibly cosmetic” issue or if it’s an indication of something not being quite right. Even if it’s only just a sound, it’s a pretty annoying one to be honest. Thanks for the reply!

 

[beretta]

The evaporator works much like a radiator or a condenser, containing lines that the refrigerant flows through.
As this happens, rather than dissipating heat, it absorbs it, lowering the temperature to about 32-degrees.
Oddly enough, unlike water, which freezes at 32-degrees, the refrigerant boils. This converts it back into a gaseous state, allowing it to absorb even more heat. This gas then flows back into the AC compressor to start the process over again.

 

[DAVE]

It is not uncommon to have an expansion valve make hissing or whistling noise at times due to refrigerant flow through the small orifice. If you have never had this before you may have to change expansion valve to correct. The shop probably changed the valve when replacing evaporator core. It is a major job changing that evaporator and because of that I would never take a chance on an after market core due to the fact most after market cores are cheaper but it is because they usually don't have the same capacity or fit as the factory. It probably is not the core making noise but the expansion valve but regardless some hissing at times is normal.

 

[Shrimpngrits]

Thank you for your thoughts guys, you’ve helped me grasp it a little better. I really wish they had let me choose wether to go aftermarket or OEM, that’s a bit disappointing to me, I’d have gladly paid extra for the OEM considering the scope of the job.

 

[Artfuldodger]

I think it's probably normal, having a different evap coil and maybe
expansion valve, plus the charge may be different, it could all make the hiss sound louder.
It seems to be a common annoyance on a google search.

What's weird is the shop explained what it was and that it was normal but then said they've never heard it before.

 

[Shrimpngrits]

Here’s what bothers me the most I think, this is a brand new shop close by that I wanted to try, they have these “concierge’s” for you which seem like a good idea; they schedule a time for you to arrive, give you text updates, tell when it’s done, what it costs, take your payment…. But when you have a technical question they give you the deer in the headlights. It’s frustrating to not be able to talk to the one that did the work on your truck.

 

[M80]

Does the noise quit when your not running the a/c

 

[hopper]

Here’s what bothers me the most I think, this is a brand new shop close by that I wanted to try, they have these “concierge’s” for you which seem like a good idea; they schedule a time for you to arrive, give you text updates, tell when it’s done, what it costs, take your payment…. But when you have a technical question they give you the deer in the headlights. It’s frustrating to not be able to talk to the one that did the work on your truck.

I always like knowing the mechanics by name that work on my stuff. A hand shake and a look in the eye when personally discussing repairs goes along way for me.

 

[Shrimpngrits]

Does the noise quit when your not running the a/c

It made the noise on every setting, It did not make the noise when system was powered off.

I’m embarrassed I haven’t updated this like I should have; the next day the shop called up and said they wanted to make it right. They replaced the evaporator and expansion valve with an OEM unit… that fixed it. The evaporator and the valve’s holes weren’t lining up right they said. -The owner heard the situation and wanted to make it right, I am pleased and impressed.

 

[M80]

It made the noise on every setting, It did not make the noise when system was powered off.

I’m embarrassed I haven’t updated this like I should have; the next day the shop called up and said they wanted to make it right. They replaced the evaporator and expansion valve with an OEM unit… that fixed it. The evaporator and the valve’s holes weren’t lining up right they said. -The owner heard the situation and wanted to make it right, I am pleased and impressed.

Awesome.