C30 General : AC problem diagnosis

[C30inFrance]

I'm mentioned the problem with my AC before. That is, not blowing cold. Since then, I've had it regassed and whilst it is better it is by no means as good as it was. Turns out they didn't replace the cabin filter, simply regassed the system. Personally, I think that's a bit poor but I guess he did what I asked so I can't really complain (even though I know nothing of these things and thought he might at least have suggested it)

I spoke to another garage about the problem (whilst he changed my rear tyres) and he kindly spent some of his time (for free) taking measurements. Driver's side air temp is 12c, passenger side is 8c - he said both should be around 4c. There was no sign of leaks. He said that he usually changes the filter and compressor/condenser (? sorry, I forget which he said) oil when he regasses a system. He says it's possible that the mixer (I'm paraphrasing) is partially blocked one side but without looking he couldn't know.

He suggested I start by replacing the filter (which I've ordered, though it was replaced at the service in 2019) and see how it goes from there. I'm dubious it'll make much difference but we'll see.

My question (after the ramble!); is there a recommended diagnosis path? I'd like, if poss, a step-by-step guide to finding the problem. Or is it simply a matter of taking it in to someone that knows about these things and hoping the cost doesn't escalate ridiculously. I'd kinda like a handle on the cost before deciding on repairs.

[domhart10]

First you need to get your system checked for leaks, most likely point of leaks will be at the condensor (This is a common fault)

If no leaks, take your front wheel off and check that your AC clutch is engaging. Make sure the AC is off, start the car and have a look at the AC clutch to make sure it isnt spinning, then turn your AC on and see if you clutch engages. If it starts spinning then that is fine, if it doesnt engage / spin then you have a clutch gap issue (Also a common fault).

To fix a clutch gap issue you will need a feeler guage as the original gap should be 0.3. There are tonnes of videos on youtube for this but I had to do this on mine.

[C30inFrance]

I eventually got around to sorting this, lockdowns etc have meant I've hardly used the car so there was no urgency.

It turned out to be the condenser and cost me a cool (ho ho) £540 to have it repaired. The garage that did it is one I've come to respect from previous experience. I'd spoken with a couple of other garages, both of whom had happily given me quotes for replacing the compressor, but neither gave me confidence since they didn't actually do (what I'd call) a proper diagnosis!

Nice to have a working AC now that summer's about to start.