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Is it normal for air con to cycle on and off?

farmerboy

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Feb 13, 2015
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Hi all, my LC3 air con cycles on and off as the pump starts up and the revs rise and fall in unison. This is most noticeable when everything is set to max cold.

I thought it was a fault and had it re-gassed at Kwick Fit - they did it for free because it did not solve the problem but I am wondering if it is normal? It is hardly noticeable when more moderate temperatures are selected and it is really cold so the system appears to be working well.

Has anyone else experienced this "cycling" of the air con system?

Thanks

John
 
I believe it's normal. What you're hearing is the AC clutch kick in and out, and when it does it puts more strain on the engine thus the engine rpm rises to combat this. I know on my 90 series it's kicking in and off often as well so it sounds pretty normal. I wouldn't say it's constantly on off on off. Maybe runs for 20 seconds and then off for a few and then back on again ect
 
As said, perfectly normal. There is, for a period, enough "cold" in the matrix inside the car. As that watts up from the gentle air blowing over it needs to rechill.

Set it to max chill and max fan and cycling should stop or at least become extended.
 
Thanks all.... glad it is all ok. I feel a bit guilty because I took the car to Kwik Fit to get it looked at - they will regas for free if it does not solve the problem... anyway, they connected it up to their machine and it removed all of the old gas, tested the system, filled up with new gas plus the other additives (oil and dye?) - took about an hour and I told them it was no different! No charge and I have to admit it is a LOT colder now... shame on me!
 
That's not a bad deal :shifty:

If they put the dye in then keep an eye out for green patches. Mine had two leaks on the driver's side, inside the engine bay where the ali pipe changes to the flexible pipe. Two 75p orings sorted it out. (You have to drain the system again though : ( )
 
I would have said its normal, mine kicks in and out but I wouldnt want to guess how often (nowhere near the truck at the moment, so can't check it).
 
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Update....

The aircon stopped blowing cold today so I took it to a local AC specialist - what a great guy - old school who fixes stuff rather than throw new parts at it! Anyway - he injected some dye and discovered a small pinhole leak in a tiny high pressure pipe which he will cut out and splice in a new piece of pipe rather than replace the whole thing - MUCH cheaper! He thought it may have been the pipes to the rear AC and said that he could just blank them off if needed rather than spend a small fortune replacing them.

Highly recommended.. http://www.cool-wheels.co.uk/
 
Have you tried the relay in the box in the engine compartment. You can swap it with an identical one which I think is for the fog light. Common fault which means the compressor fails to switch on. Normally the air con light switch flashes.
 
Have you tried the relay in the box in the engine compartment. You can swap it with an identical one which I think is for the fog light. Common fault which means the compressor fails to switch on. Normally the air con light switch flashes.

yes - tried that but no change. The problem was a leak in one of the pipes - they cut out the bad bit and spliced in some new. Very good (if a bit scruffy) aircon specialist.
 
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