Whistling sound after replacing condenser

I'd give it some time... If the AC keep blowing cold than it's not a leak. If it is a leak go back to shop and ask them how come they charged you to check for leaks and they didn't do what you paid them to do.

 

And then after you get out of the car and walk away or begin to how long will that whistling continue till you get tired of standing there or does it stop almost immediately?

 

If I'm not mistaken on the side of the factory type condenser for the air conditioner in front of the radiator there's an accumulator or a tank on one side and it may be just the gas accumulating and settling down after running. It may not be as quiet as the original unit for whatever reason some of these newer things have smaller ways and passages and the things and what have you which can be a problem sometimes it's not. If it's a factory direct replacement I might want to make damn certain that my gas charge and everything is seriously correct I realize it was done at a shop for money so there's that You can take a long coat hanger or something like that a mechanic stethoscope was a long piece of metal on its pickup and listen to I think it would be the right side of the condenser that's where that little accumulator looking tank is if I'm not mistaken it is on my '05 anyway and listen and see if that's where the noise is emanating from You can probe around with the mechanics stethoscope and see if you can isolate the noise to a certain spot on the condenser in the hose in the compressor obviously this is off so everything should be fairly safe.

 

A true whistling sound results from gas moving through a small hole. That shouldn't be happening anywhere in the AC system. If your car does that reliably give the AC shop a call, tell them you're coming in, and have them listen to it when you get there.

 

Catch is the shop was paid to find those leaks and they said they didn't find any... Hard to imagine something came loose on the drive home, but until the AC stops running cold, it's probably best to update the shop about the symptoms and wait for things to change.

 

"Shop doesn't want to hear about it" isn't a sign that the shop is very trustworthy. I'm trying to think of a situation where a whistling sound isn't indicative of a problem in a car, and the only thing I can come up with is whistling from the windows due to a cross wind. In this case we know it's the AC because the OP only hears it when the AC has run, and it sounds like it is coming from near the condenser that was just replaced. I would take it to a different AC shop for a second opinion, and arrange the appointment so that they have time to listen to the noise immediately on arrival.

 

Because the shop is in the Netherlands and subject to far more strict EU consumer regulations compared to the US, I'd be willing to bet the shop is basically saying get in touch if the AC stops working, but how it sounds doesn't concern us as long as its working. And its pretty common for shops to have very little patience for people concerned about strange noises if the car is working fine without any issue but the noise. I tend to be the same way.

 

Is it possible that one of the valves is leaking? The shop wouldn't have seen that since they would have had their equipment attached to them.

 

Time will tell... If OP doesn't return to update it's likely that everything is fine and weird noises in old cars is nothing to get on about.