AC Overcharged, Undercharged? Forget It, Jake. It’s the Gap.

I don’t want to make another blows cold then blows warm* post, because there are several of those already, but I do want to highlight Volvo DIY wizard Jimmy57’s explanation on this AC clutch gap problem, because it’s perfect.

* undercharged, overcharged, or just right — doesn’t matter

Let’s start with the question:
ThreeBear, new MVS Forums member »

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.

Jimmy57’s outstanding explanation »

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.

Overcharged, Undercharged, Forget It. It’s the Gap.

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