Hello. I'm from Italy.

I have a brand new Ford Ka 1.2 with automatic AC.

When I switch on the AC sometimes i hear a whistle noise when the engine is from 2000 to 3000 rpm.

Some ideas?

Thanks.

Does this noise happen with all blower/heater/ac fan speeds?

Does it change pitch or go away if you move the selector from hot to cold or from vent to defrost or heater,etc.?

 

Vacuum hose or tube failure - can you isolate where it is coming from?

OPen the bonnet and see if you can locate the whistle - if its a leak in the ac hoses you will soon loose all cooling!

http://www.youfixcars.com/air-conditioning-noises.html

"Does this noise happen with all blower/heater/ac fan speeds?"

Yes.

 

" Does it change pitch or go away if you move the selector from hot to cold or from vent to defrost or heater,etc.? "

No. Change pitch only over 2500 rpm and is more persistent when the weather is hot and wet.

 

"OPen the bonnet and see if you can locate the whistle - if its a leak in the ac hoses you will soon loose all cooling! "

The car make the noise only when is in motion, over the 3rd gear. The noise come approxymately from the timing belt area.

 

"http://www.youfixcars.com/air-conditioning-noises.html"

I previously found this page but doesn't help me.

Thanks for reply.

 

Yes I think the problem is definitely with the the A/C (air conditioning) compressor - it could be the impeller, ac clutch or bearing is failing or a common problem is the supporting bracket works its way loose. The bracket will need to be realigned and tighten the four bolts.

Either way i would take the compressor off and examine it if you are able and have the tools.

 

Thanks for reply :)

Replaced A/C compressor and expansion valve. The whistle is still here :-(

Why didnt you just test the compressor rather than buy a new one , its easy to see if its faulty?

Did you check the system for leaks ie all the hoses and simplest things first?

Its usually sods law and comes down to the simplest of issues!

 

13 hours ago, Omendata said:

Why didnt you just test the compressor rather than buy a new one , its easy to see if its faulty?

Did you check the system for leaks ie all the hoses and simplest things first?

Its usually sods law and comes down to the simplest of issues!

 

Car has 3 months and is in warrany. The seller has checked the system and changed expansion valve and compressor for free.

Also the Ford assistance has no idea to what to do. 

It then  needs a full AC service from the garage.

I could suggest what to do to isolate where its coming from but as you are not fixing it yourself and its in warranty then its up to the seller to fix it.

 

Thanks for suggestions.