Air conditioning Whistles
 

I have a 1997 C280. The air conditioning whistles (an up and down whistle). It doesn't matter which fan speed I have it set to. It's a very distracting and annoying sound. I recently replaced the cabin filter about a month ago, but this noise just started. I took out the cabin filter and put it back in, but this had no effect. Could the unit be low on freon? What should the pressure read on the low side?
Any help is GREATLY appreciated.

Hi,

Did you do a search? I seem to remember something about that before, a years or so ago.

Mike

Air Conditioning Whistles
 

Thanks for respondig. I haven't had any luck searching. The question is out there but no answers.

Hi,

In this thread it was a vacuum leak at an actuator and the whistle changed with engine speed: http://www.peachparts.com/shopforum/tech-help/65000-whistling-hvac-system.html

In this thread they are suggesting it is the motor/regulator:
http://www.peachparts.com/shopforum/tech-help/63734-c-problem-c230k.html

Mike

This is dumb I know but I had a whistle also and it was the passenger side dash vent being almost closed. Opened it up and the whistle was gone. Hope yours' is that simple.

I have the same sound in my E320 I think it's something with the vents acutators but I think it*s no nice job to fix that so I leave it for now if it's get worse I have to look in to it there is not so often it will whistle so I can take it for now.
I don't think the cabin filter is the problem why should the noice only occur in AC mode then?

Air conditioning Whistles
 

Mike,
Thanks again for your responses. Do you have an image of where the actuators and vacuum lines are located?

Sorry I don't have anything. But those threads I referenced gave decent explanations I think. Maybe someone else can provide a picture for you.

Mike

That thread regarding the actuator pod was mine - I have pics and will try to dig them up. They were NOT easy to get to; I assume the dash would normally have to be removed to access them.

Keep in mind you were working on a W210 and he has a W202 so they might be different. I have no idea.

Mike