2004 S60 AC Overcharged?Undercharged? (RESOLVED:Clutch Gap+Overfilled) Topic is solved

ThreeBear · Post by **ThreeBear** » 02 Jul 2018, 09:15

2004 Volvo S60. AC blows warm after initially blowing cold.

Issue: On warm days (over 75) my AC will start blowing cold and then start blowing warm air. On days under ~75 it will blow cold on all settings and seems to work great.

Last fall I recharged the system because the air was not blowing cold and the AC compressor would cycle almost constantly at idle and would make a very distinct 'click' sound when coming on and off. After I recharged the compressor cycles VERY slowly at Idle perhaps as long as 60seconds but the distinct 'click' sound is less pronounced.

I have tried to find information about what the low pressure numbers for the S60 should be but haven't been able to find anything. The information I have found is usually a single number for lowside, my lowside bounces between two numbers as the compressor cycles.

Information.
-AC Compressor gap is .3mm (checked with feeler gauge)
-Lowside pressure when idling bounces between ~29psi and ~40psi

Do I need to add more refrigerant? My lowside pressure is right between the 'fill lines' on the gauge but I do not know if those are universal or apply to Volvo.

Post by **jimmy57** » 02 Jul 2018, 09:41

You are describing the problem where clutch wears and the gap between the belt driven pulley and the plate on the compressor chaft gets too large. The electrical winding gets warm from being energized and the magnetic strength falls when wiring gets warm and current flow goes down. Cool weather affects it positively. If it goes warm and you turn the system off for 5 minutes and it cools again for a period then that is a sign of this problem. The compressor will be switched off periodically if the evaporator gets too cool. This happens once it cools down the interior. Once the compressor goes off then the excessive gap issues rears its head.
Lots of articles in this site about it but from a point of view of someone who works on these often the only way to fix it is to lower subframe so the compressor is accessible and then use a puller to remove the plate. The gap is set by washers so removing one of the washers and then putting plate back on completes the fix. If the compressor is noisy or has any issues then replacing the compressor is indicated then.

ThreeBear · Post by **ThreeBear** » 02 Jul 2018, 10:12

jimmy57 wrote: ↑02 Jul 2018, 09:41 You are describing the problem where clutch wears and the gap between the belt driven pulley and the plate on the compressor chaft gets too large. The electrical winding gets warm from being energized and the magnetic strength falls when wiring gets warm and current flow goes down. Cool weather affects it positively. If it goes warm and you turn the system off for 5 minutes and it cools again for a period then that is a sign of this problem. The compressor will be switched off periodically if the evaporator gets too cool. This happens once it cools down the interior. Once the compressor goes off then the excessive gap issues rears its head.
Lots of articles in this site about it but from a point of view of someone who works on these often the only way to fix it is to lower subframe so the compressor is accessible and then use a puller to remove the plate. The gap is set by washers so removing one of the washers and then putting plate back on completes the fix. If the compressor is noisy or has any issues then replacing the compressor is indicated then.

Thanks for the information. When I checked the Clutch gap it was at .3mm which I believe is inspec. I tried to push the plate out further but was not able to so I think the max gap is .3mm.

Post by **Rattnalle** » 02 Jul 2018, 10:39

. 3 should be OK. But it really does sound like it's the issue.

And even if you do need to get to it it's doable without lowering the subframe, that's just extra work unless perhaps you have proper equipment.

Post by **oragex** » 02 Jul 2018, 10:56

Do you mean, it blows cold, then warm, then cold again and so on? Does this correspond with the clutch plate spinning and stopping?

Same with the needle, does it bounce related to the clutch engaging/disengaging?

ThreeBear · Post by **ThreeBear** » 02 Jul 2018, 11:00

oragex wrote: ↑02 Jul 2018, 10:56 Do you mean, it blows cold, then warm, then cold again and so on? Does this correspond with the clutch plate spinning and stopping?

Same with the needle, does it bounce related to the clutch engaging/disengaging?

If it is hot out, it will blow cold for ~3-minutes and then blow ambient/warm. The only way to get it to blow cold again is to turn it off for awhile and then it will blow cold for ~1minute before warming up.

The needle does bounce between high(40psi) and low(29psi) as the clutch cycles on and off. Perhaps I just need a recharge? I do not know what ranges are required for the s60.

Post by **oragex** » 02 Jul 2018, 12:39

That really sounds like the typical clutch issue, assuming the gap is fine, may meant the clutch is worn out - still check the small wire to the compressor just in case is not secured properly. The clutch magnet is influenced by the temperature of the compressor, as the clutch gets worn (or gap gets too large) it loses strength and disengages when the compressor warms up while it's running, causing the air to go warm.

As for the pressure I'd say is fine, 30 psi with the clutch spinning is your low pressure value and is just about right (when it stops the psi goes up, it's normal)

Replacing the clutch (and the bearing in the process) is not that bad and I'd use a used plate www.youtube.com/watch?v=KAGDkwYSFY4

dj_v70 · Post by **dj_v70** » 02 Jul 2018, 14:12

Oragex,

Wouldn't it be best to put a voltmeter on the compressor power lead? Then he could monitor the system while engine is running and clutch disengages. If voltage present after disengaging, the compressor/clutch needs work. Else, there might be an issue with the control system.

ThreeBear · Post by **ThreeBear** » 02 Jul 2018, 14:45

oragex wrote: ↑02 Jul 2018, 12:39 That really sounds like the typical clutch issue, assuming the gap is fine, may meant the clutch is worn out - still check the small wire to the compressor just in case is not secured properly. The clutch magnet is influenced by the temperature of the compressor, as the clutch gets worn (or gap gets too large) it loses strength and disengages when the compressor warms up while it's running, causing the air to go warm.

As for the pressure I'd say is fine, 30 psi with the clutch spinning is your low pressure value and is just about right (when it stops the psi goes up, it's normal)

Replacing the clutch (and the bearing in the process) is not that bad and I'd use a used plate www.youtube.com/watch?v=KAGDkwYSFY4

Thanks for the update. Based on the feedback perhaps it is the clutch gap. I checked it and it seems small but perhaps the gap increases as it gets warmer. I did check the 12v wire to the clutch and it is plugged in and looks okay. Is there any chance this is the thermal cutout switch from the compressor? I have seen that reported for some version of Volvo (although nothing about S60). Thanks for your help.

zjevik · Post by **zjevik** » 02 Jul 2018, 22:54

I had a similar problem. I charged my AC at idle and it was working at idle without problems but once I start driving it turned off in a few minutes. It's important to keep the engine around 1200 rpm when you charge the AC using the low side pressure. The compressor has variable efficiency and you will overcharge the system if you do it by the pressure at idle.

Try to see if you overcharged it or take it to a shop where they can measure refill your AC by weight.