Any car air con experts on here...

Thanks in advance to those who advise I wind the windows down.

The A/C in the wife's mk3 mondeo dream machine has started to play up. Regassed last year, worked fine since. Today started off, cranked it up, worked a treat, couple of miles in stopped blowing cold air and started blowing warm and damp air. Switched it off and back on again a minute later. Worked again for a bit then off. Any ideas on this, going to try and get it regassed tomorrow (which will hopefully remedy this) but could do with it sorted for the weekend, got a fair trip coming up.

What seems weird is that it worked again for a bit. Makes me think it would be nothing to do with the refrigerant.

You can get it checked for free, I think, at Halfords.

Crikey, just noticed you were looking for experts. Sorree!

Yeah, I'd guess perhaps not gas. Hoping its borderline or something, know the system has a low pressure cut off.

Classic symptoms of the compressor clutch being worn outside of tolerances.

Air con works fine for a while, then under bonnet temps mean the oomph to engage the clutch is just a bit too much for a widened gap.

When the under bonnet temps decrease, air con starts working again, because the gap can be just about bridged.

If you can see the clutch gap, physically, you may be able to check the gap with feeler gauges, if you know what the spec should be. On the car I sorted this on, it should have been 0.4mm, but was around double that. Low gas pressure is often contributory as it can make the compressor have to cycle on and off frequently, in turn causing additional wear to the compressor clutch surface.

What I did to solve it, bought a used compressor from ebay, someone in the family made a metal plate to act as clutch puller for this compressor, removed the clutch plate and ground down one of the shims / washers for the clutch plate, until it was correct spec. Then had an air con guy swap over the compressors and regass.

I reshimmed the original compressor since it was then off the car, so it was back to spec, too.

Thanks Neil. Something I'd come across in search before > http://www.honestjohn.co.uk/forum/post/ ... tm?t=63198 , seems to be something common with the Mondeo. Ford sell a shim kit which I've ordered the shim kit from my local dealers this morning, worth a go tomorrow...

Suppose if the compressor cycles on and off in use (as I believe it does) then it's quite possible this could be the cause. Going to try and get the refrigirant checked whilst I'm at it.

John":38ggmur7 said:

Thanks Neil. Something I'd come across in search before > http://www.honestjohn.co.uk/forum/post/ ... tm?t=63198 , seems to be something common with the Mondeo. Ford sell a shim kit which I've ordered the shim kit from my local dealers this morning, worth a go tomorrow...

Suppose if the compressor cycles on and off in use (as I believe it does) then it's quite possible this could be the cause. Going to try and get the refrigirant checked whilst I'm at it.

Click to expand...

Just read that thread - good news that there is a shim kit, and access is reasonably easy to sort this.

In a lot of cases, garages would simply say you need a new compressor - they don't tend to do much at all (if anything) directly with air-con. The regas things, these days, tend to be all automated - hook it up to the ports, tell it the make and model, then leave it do it's thing.

As to compressors, I've seen them operate in two manners - engagement of the compressor, via the clutch, dependent on several sensors and factors, low gas causing the compressor to cycle every 5 or 10 seconds - this is the scenario, where the compressor is cycling more frequently than it should, that probably results in notable wear to the clutch plate.

On other systems / compressors, so long as there's some minimum gas pressure, the compressor will engage, and pretty much stay engaged permanently, until you turn of A/C, but gas pressure appears to affect the vent temperature / cooling, and presumably other aspects of how the compressor is operating.

If it's blowing cold, now, when the compressor will engage, then it's reasonable sign that there's a decent amount of gas in the system. When it does work, what's the sort of time between the clicks of the compressor cycling?

I had the same issue on my Volvo S70 cold air for a bit then warm air. Turn it off or a bit and it would blow cold a bit then warm up. A 2nd hand compressor duly was purchased and fitted which turned out to have a leaky o ring so re gassing was needed after all (again)

However that was eons ago (6 plus years) and it's still blowing cold steadily now

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

Love it, garage would have just replaced the compressor and relieved you of probably 500 quid for the job, all done for 8 quid and an hour or so of your time.

Carl