S70T a/cond and power

bigkev414 · Post by **bigkev414** » 29 Nov 2011, 06:55

The S70T I recently bought gets 'knocked flat' whenever the air cond. compressor cuts in - I havent had one for years but seem to remember they do this? Is this right? Cruising at say 80km/h and it knocks it down by 5 or 6 ks and I have to put my foot down a bit harder.
Also noticed today after driving for about 2 hours in 32 degrees plus with very humid conditions that the compressor cut out and just refused to come back in for a while - turned the switch to off, waited a couple of minutes and then switched back on and it was OK. Could it have iced up in the extreme humidity I wonder? Noticed the last week or so a soft buzzing noise intermittantly from behind the centre of the dash and some clicks like a relay was cutting in and out. Are there any relays behind the a/c control buttonS in the console? The air is very cold instantly and the car is in 'show' condition and there is no indication that the compressor or condensor needs attention.
Ideas appreciated. Thanks, Kev

Post by **Ozark Lee** » 29 Nov 2011, 07:17

The power loss leads me to think that you may have the system overcharged. My N/A cars do have a noticeable decrease in power with the AC on but not my turbos at all. An overcharged system will cause the compressor to overheat and the thermal switch could be cutting out on you.

If you can get us some pressure readings along (both engine off and engine/compressor on) with ambient temp readings we can likely make more sense of your problem. When you give us the temps be sure to specify Celsius or Fahrenheit. Either way we can convert it.

...Lee

Post by **jblackburn** » 29 Nov 2011, 11:42

Eh. The AC zaps all the power from my S70. Might be the different compressor used between the years or something. I always forget about how fun it is to drive during the summer until I go somewhere with the AC off and it feels a few hundred pounds lighter on its feet.

Run 93 gasoline in it if it's hot outside, and you'll get a better powerband than running on 87/89 AND running the AC.

Here was my thread:
https://www.matthewsvolvosite.com/forums ... =1&t=39305

bigkev414 · Post by **bigkev414** » 03 Dec 2011, 02:26

thanks guys
the compressor cut out again today after about an hour of stop start city driving and wouldnt cut back in. After the car had been stopped and turned off for a few minutes it was OK again. I'll take it in and get the pressures checked, but in the meantime anybody else with an S70 experienced this? Controls all work right, air is very cold and the climate control thermostats operate properly. Sounds like a cutout as suggested?

Post by **jblackburn** » 03 Dec 2011, 04:22

Happens often. Search air conditioning bread clip fix.

bigkev414 · Post by **bigkev414** » 03 Dec 2011, 05:46

jblackburn wrote:Happens often. Search air conditioning bread clip fix.

Don't understand what that means mate....can you please help some more? thanks, Kev

Post by **JRL** » 03 Dec 2011, 06:01

Search the DIY area
Your compressor clutch has failed, (failing) common with this type of system with over 100K miles and 10-14 years (or more).
You need to shim out the clutch gap and this can be done with those little plastic clips that come on the end of certain loaves of bread, (you need 3).
Actually fairly easy to do and sometimes (if you're lucky) this fix can last for years.

bigkev414 · Post by **bigkev414** » 03 Dec 2011, 06:37

Looked it up, thanks. Now I get it. Nothing beats experience, thanks again. Kev

bigkev414 · Post by **bigkev414** » 29 Feb 2012, 19:39

Posted a while ago that the climate control A/C in my car plays up intermittantly - on very hot days and especially during stop - start driving the compressor cuts out and won't cut back in. Stop engine, wait a minute and start up and its OK again. Also, when it has cut out the fan speed is very low and won't respond to the slide adjustment.
I had the clutch looked at (breadclip fix thought) and it's OK.
I think it must be electrical problems with the controller, but maybe that's because I am a retired electrician. Sometimes there is a 'clicking' noise like a relay chattering from that area somewhere and a low 'fizzing/buzzy' noise that stops after a while. Any ideas please?