2005 Rover 75 Air-con

[norseman]

It could mean that the compressor has become stiff to turn, for one reason or another.
Try the same test with the engine on tick over, then switch the A/C on......does the engine slow up a bit?
John

My old 5 series does the opposite. Hit the a/c button at idle, hear the compressor engage & the revs increase marginally.
No noticeable difference in performance when the a/c is in use.

 

[Koolpc]

Can it cause any long term issues? I heard the compressor can be expensive to replace.

 

[Burnerman]

The car's ECU will increase the idle RPM to compensate for the load on the compressor.

In this case I'd be inclined just to leave the A/C off until the fault is properly diagnosed, and expect around £250 for a small hatchback compressor.
John

 

[Koolpc]

The car's ECU will increase the idle RPM to compensate for the load on the compressor.

In this case I'd be inclined just to leave the A/C off until the fault is properly diagnosed, and expect around £250 for a small hatchback compressor.
John

Thought as much. Ta

 

[Avocet]

Whenever I got my Aircon on I find the car sluggish to accelerate at low speed. Turn the Aircon off, it's fine. Does that mean air con unit failing?

What's the car and what sort of engine power? A car aircon pump, at startup, will take maybe between 3 and 10 horsepower.

 

[Koolpc]

Citroen C1 2016

 

[Avocet]

Citroen C1 2016

OK, I'm guessing not very powerful then. In which case, yes, I think I'd be able to spot a slight drop in power each time the aircon pump cut in - especially at light throttle openings.

I've no idea if the C1 is set up this way, but plenty of manufacturers cut the power to the aircon pump if the throttle pedal is pressed to the floor, so as to maximise engine performance. As soon as you come back off full throttle, the power to the aircon pump is restored. My guess is that there might not be anything wrong with the pump. Does the drive belt squeal when you first switch the aircon on? They also tend to have safety switches so that in the event of a blockage and the pump running at too high a pressure, it cuts the power to the pump. Has the car always felt like this, or has it only just started doing it?

 

[Koolpc]

No squeal.

Not sure if I have noticed before. Just seems a bit sluggish when in low gear. Once past a certain point it goes ok. It's only when Air con on..