Any car air con experts on here...

John":393qeax4 said:

Decided to try reshimming the AC compressor clutch given it seems common on the Mondeo. Picked up the precision shim kit from the dealers today (£8 for 5 shims, beauty). Apparently the internet mechanics who have the strength of the Incredible Hulk and dexterity of a Geisha Girl can do this job in 30 mins. Took me a bit longer, main problem was getting the clutch off, access was really tricky, the pump was right up against one of the bulkheads, could barely get the ratchet in. Still came off eventually, old shim off, thinner one on. Jobs a goodun so far, compressor seems to come on and off ok whilst in operation so fingers crossed

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When I did mine - and like the other poster in this thread, uncannily, it was also on an S70, there wasn't much room down there, and I really didn't want to have to remove it myself.

I found having had a tool made (that lined up with holes in the clutch plate, and once it was undone, worked like a make-shift clutch puller - even then took a fair bit of effort. Then "pop" the clutch plate was off.

Good test for it being the clutch gap being driving around for a good half an hour or so, and the air-con working constantly in that time - assuming that's OK, then sounds like it was the problem.

If the vent temp is pretty cold, and the compressor isn't cycling too frequently - a good 40 or 50 seconds at least, or a fair bit longer, in this heat, is a good sign. If it's in the range 5-20 seconds, in this sort of temperature, it's a hint that the gas pressure is probably a bit low.

The audible click of the clutch / compressor engagement tends to make it reasonably easy to time.

Mondeo sounds a bit easier than the Volvo at least, should be grateful for small mercies.

Took it out for a while in traffic in the afternoon heat and it clicked on and off and worked great for the whole trip. Which is a good sign.

Compressor doesn't seem to be cycling too much although it's certainly on more than off but that is no surprise in this weather. afaik the mondeo compressor won't operate if the pressure is too low.

Had arranged for the mechanic I use to check the refrigarent tomorrow. Any idea if it's possible to just check the amount? Or is the only option to get it vacced out and refilled?

John":109ci4uq said:

Mondeo sounds a bit easier than the Volvo at least, should be grateful for small mercies.

Took it out for a while in traffic in the afternoon heat and it clicked on and off and worked great for the whole trip. Which is a good sign.

Compressor doesn't seem to be cycling too much although it's certainly on more than off but that is no surprise in this weather. afaik the mondeo compressor won't operate if the pressure is too low.

Had arranged for the mechanic I use to check the refrigarent tomorrow. Any idea if it's possible to just check the amount? Or is the only option to get it vacced out and refilled?

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You can check the pressure, at least - Halfords and the like sell gauges, and you don't need to use one of their top-up cylinders just to check the pressure. The latest ones they sell, have a handy little thing that you swivel around which shows you the acceptable range, given the current ambient. Not perfect, and something of a blunt tool, but would give you an idea.

The only connect to the low pressure side, though - the only Mondeo air-con I ever tinkered with was on a Mk II R reg, some years ago, so don't know whether your model definitely has a low-pressure port (some cars don't). But the connector should only fit on a low pressure connector, the size should be different for the valve on the high pressure side.

So long as it's not cycling quickly, and the vent temp is cold, and it's staying on, though - it may well be fine - good enough not to need any.

I think the pressure gauges are maybe around £15, though - and really only a blunt tool, really - when proper A/C guys - or more likely, these days, the automated trollery machines, they should be adding the correct weight of gas and lubricant to the system.

Some people are vehemently against the top-up kits - and I get their point - but if all you really need is a little gas adding, with care, and a pressure gauge, so long as you're sensible, they can be reasonably cost-effective at minor top-ups. I'll qualify that by saying, clearly that's inferior to a proper evacuation, holding a sustained vacuum for a good period, then adding the correct weight of gas and oil.

Compressor clutches can glow red hot and start fires if they go South. Had this happen to me in my daughter's Corsa a few years ago, and up in flames it went. If the clutch is suspect just replace it.

I wish I never read this thread, our S Max blower has just started playing up. Vibrating loudly at 8-10 speed.

Probably easy enough to sort, but likely a nightmare to get at.

Chopper1192":2m4evuyu said:

Compressor clutches can glow red hot and start fires if they go South. Had this happen to me in my daughter's Corsa a few years ago, and up in flames it went. If the clutch is suspect just replace it.

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Realistically, that's only going to happen, if the clutch is worn out of tolerance - and shimming it - especially with an official kit, is likely to put it back to spec. In which case, there's no reason for any extreme build-up of heat.

Some marques do provide clutch kits, others provide shim kits. I suspect it's the lack of action on either, that would cause a compressor clutch to get to the point where it could cause a fire.

And usually, the reason why a compressor clutch wears beyond tolerances, is some fault or condition that results in the compressor cycling much too frequently (usually low gass pressure), which in turn causes additional wear. Somebody who doesn't realise that, ain't likely to be paying attention to the condition of the compressor clutch, either.

Compressor clutch gap brought back to spec, is a reasonable repair - compressor clutches wouldn't just get to the state where they could cause a fire either overnight, or without being detectable - unless it was some obscure, catastrophic failure.

It goes without saying (or should at least) that people should be happy about doing DIY jobs on their car before doing so, and if in any doubt seek the advice of a professional. In this sort of instance, though, you'd probably find most (I suspect main dealers at least) would probably be dismissive and suggest a new compressor was required. Some independent, decent air-con mechanics may well be good enough to correctly diagnose and be willing to do all that's required, but in a lot of cases, where air-con is concerned, with a lot of people, once the problem has started to exhibit, and the price of repair far eclipsing the cost of a regas, most won't bother.