Air con

[john & Jake the dog]

Hi, When the air con is used the idle speed of the engine fluctuates between normal and 1100 revs.
Is this normal please.

 

[coachwhip]

Air con uses a lot of power, so the engine has to work harder. If the engine management didn't keep adjusting the idle then you'd probably find the car would stall.
Mine does the same when I put both windows up together. Tries to stall then gets a little burst of power to keep it idling.

 

[john & Jake the dog]

All normal then, cheers.

 

[JSP]

I too have this, but a couple of people have suggested that I replace the alternator with one that has a higher output.

Has anyone done this and if so what alternators are compatible?

Many thanks, in advance.