rev drop when air con turned on

[ritter1]

hi guys, was turning my 1.4 mk3 golfover today when I turned the airconon all the way to '4' and the revssuddenly dropped by like 100/200 revs. Never noticed this before, but seeing as ive never turned the air cononlike this while sat still idling i wouldn't. Just wondering what it might be, thecar runs fineandit doesnt seem tobe a problem,just curious what itmaybe. Like imentioned, it drops the revs but then raises straight back to the revs it was doing before the air conwas turned on. I thought it mite hav bin thefact the air con was on as hot as it could go and seein as it had only just gotten to normal temperature (the engine), it was a bit of a struggle or sumthing but then turned the air conoff and turnedit straight back to4 on full cold andit did the same.

Any ideas?

[Crasher]

Air con on a 1.4? I think you just mean the heater. Yes, a rev drop is normal on high blower speed, the blower takes a lot of current which puts strain on the alternator and pulls the engines idle speed down.

[ritter1]

yeh,it is just the blower, im just in the habit of sayin air con cos its just easier and quicker lol. should it drop by like 200 revs tho? the same thing happens when you puton fulllock either to the left or right as well, the revs dontdrop at all till you hit absolute maxiomum lock, even the slightest amount under full lock doesnt seeany drop in revs.

[Crasher]

Yes, that is normal.