13 hours ago, Alex.S said:

I’ve looked at the mk4 manual on the app about this , can’t find a straight answer..

There isn't a straight answer...

In theory, regular use keeps the seals supple.  In practice, I've had cars with leaky AC at 5 years old (Vectra C, Mk3 Focus), and cars at 10 years old with fully functioning AC and not so much as a regas (Mk2 Focus, Mk4 Golf)...

My Mum has owned 2 near identical Suzuki Swifts, she bought one new, one slightly used, AC has been left on permanently in both - one had leaked by 6 years old, the other is still going fine now...

Seeing as how poor the Mk3 Focus AC system was, I'd probably run the Mk4 system regularly just in case its still as poorly built!!   In my 100k Golf (that has even suffered a front end crash and has bent AC pipes) the AC still works perfectly and I only use it during summer, except when I accidentally turn the screen demist dial too far and it comes on on its own lol...  

You're welcome to try a tank of fuel with the AC on and another with the AC off, to tell us how much fuel consumption changes on a brand new car, I've never had anything later than 2012 to try it on.  I've found it is a considerable change though and can't justify the extra fuel in my financial situation, that's the sole reason I only use it when absolutely necessary - others seem to notice little to no difference though...  

14 hours ago, iantt said:

In winter it keeps the windows demisted. On my Mondeo it's got climate control so it does it's thing whatever the weather. Set to 20c and auto all year round. Only exception is on a very cold frozen morning when it's max defrost setting, putting both heated screens on, PTC heater on fan on high on screen max heat. 

Does your s/s work while air con is on? I have climate control, does that mean the air con won’t kick in unless the air temp is high? 

On my previous Ford it said that I had to use the aircon for at least 15 minutes a week to keep the seals working but not to use it if the temp dropped below 4^oc., otherwise it would freeze and ruin the condenser.Now I have climate control I just leave it on all the time and it sorts itself out.

10 minutes ago, billyboy said:

 but not to use it if the temp dropped below 4^oc., otherwise it would freeze and ruin the condenser....

I would love to see the official printed instructions that stated this. If such an action would cause catastrophic results, they would have automated this action to preserve the integrity of a very expensive system?

I've had previous vehicles including Ford where the handbook has recommended running the aircon periodically to "maintain" the system.

2 minutes ago, Comares2001 said:

I've had previous vehicles including Ford where the handbook has recommended running the aircon periodically to "maintain" the system.

Yes, a very common instruction, but I've never seen one where it says not to use it when it is a certain temperature...

He didn't say old his previous Ford was...  The modern ones just don't allow the compressor to kick in under 3c so there's need for an instruction like that.  If his previous car was old enough not to have a CANBUS linked ambient temp sensor then it seems like a fairly sensible safety measure.  We're so used to everything being foolproof and failsafe now that we forget we used to have to use common sense to avoid damaging things!  

Tom, I'm a devotee of car user manuals, and can often be seen reading them for fun (yes, I know, it's an illness). I've had plenty of old cars and can't recollect any 'don't use if cold' instruction for my A/C. Plenty of pre CanBus ones, like my 1990 RS Turbo, 205 GTi etc, all with A/C. Oh well, as I kept the A/Con permanently, there would be bound to be time when the temp was low, and they all survived LOLK

A lot of stuff being chucked around in this thread. Let's make some very quick bullet points:

• An aircon system "maintains" itself when it's on and in-use, as it stops seals from drying out. If you only use the air con very rarely, there's a good chance your seals will dry and let the gas escape requiring frequent re-gas or even more maintenance in the form of seal replacements etc.
• The air con won't kick in under a certain temperature, on Ford's it's usually around 6-7C, newer ones/other manufacturers might be able to work a few degrees lower though. It certainly seems to be about 6C on my Mk3.5 Focus. This is an automatic protection, so even if the AC button is ON (or the A/C OFF button is not lit) then the system won't kick in - you don't need to turn it off!
• Yes, it uses a bit more fuel, but you get lovely, dry, conditioned air coming through - this is a trade-off I'll take.
• Stop/start will still work with AC on, but only if the climate isn't demanding a high load. If you've got in the car on a hot day, the climate control will be working hard for 10-15 minutes. There's a good chance the climate control system will be "demanding" cooling after this time, giving the impression stop/start isn't working. It's fine - the s/s system will work again when the car deems the load isn't too high. Don't forget, climate control systems also have a "sun load" sensor in the car, so if it detects that there is a lot of heat from sunlight, it'll work harder to counteract the greenhouse effect of a car being full of glass letting in the heat and trapping it.
• If the system is ON (and temp is above frost protection temp) the system is on all the time. The A/C system also dries the air, which is very useful, so the system works all the time, not just when the temp in the car is high enough. The compressor needs to do less work in lower temperatures so it'll naturally be kicking in and out less compared to a summer's day with blazing sunlight.

 

Personally, every car I've ever had I just press the AC on button and it stays that way forever - and you should too. The car will look after itself.

Edited February 20, 20206 yr by karlbbb

1 hour ago, karlbbb said:

The car will look after itself.

I’m going to give it a try, s/s didn’t work today but that might be coincidence. I’ll reset the mpg , was at 29mpg . 

Conflicting answers on google and Ford have done a ‘no comment’ in their owners manual. 

I’ve got climate control, if I have the air con button on all year , will the aircon be working even when it’s winter and heaters are on? 

My experience with air con is Vauxhall’s, and used noticeably more fuel. 

The focus is my first car with climate control. 

17 minutes ago, Alex.S said:

I’ve got climate control, if I have the air con button on all year , will the aircon be working even when it’s winter and heaters are on? 

My experience with air con is Vauxhall’s, and used noticeably more fuel. 

The focus is my first car with climate control. 

I've bolded your question - as per my post, yes, aircon will be on even when it's winter and heating is required, but only as long as the temperature outside is above 6C. Again, don't worry, the climate control takes care of everything, it just adds heat to the air-conditioned air.

 

Honestly, with climate control, just set a temperature you find most comfortable, press AUTO, leave it to its own devices. That's the beauty! When I bought my car, I set to 20C, and haven't touched it since.

22 minutes ago, karlbbb said:

...it just adds heat to the air-conditioned air...

 

 

And there we have it. As stated originally, "A/C" simply removes the moisture from the air (hence why it will demist all the internal glass). Over time, people have mis understood that it is simply a 'temperature' thing, it isn't. You can have cool A/C, and warm A/C...

6 hours ago, TomsFocus said:

There isn't a straight answer...

In theory, regular use keeps the seals supple.  In practice, I've had cars with leaky AC at 5 years old (Vectra C, Mk3 Focus), and cars at 10 years old with fully functioning AC and not so much as a regas (Mk2 Focus, Mk4 Golf)...

My Mum has owned 2 near identical Suzuki Swifts, she bought one new, one slightly used, AC has been left on permanently in both - one had leaked by 6 years old, the other is still going fine now...

Seeing as how poor the Mk3 Focus AC system was, I'd probably run the Mk4 system regularly just in case its still as poorly built!!   In my 100k Golf (that has even suffered a front end crash and has bent AC pipes) the AC still works perfectly and I only use it during summer, except when I accidentally turn the screen demist dial too far and it comes on on its own lol...  

You're welcome to try a tank of fuel with the AC on and another with the AC off, to tell us how much fuel consumption changes on a brand new car, I've never had anything later than 2012 to try it on.  I've found it is a considerable change though and can't justify the extra fuel in my financial situation, that's the sole reason I only use it when absolutely necessary - others seem to notice little to no difference though...  

interesting post, I bet the ones that failed have the later design of condenser made out of tin foil, where one winter's salt wasn't washed off because its not a daily driver or a bad winter with salt in use for many weeks.  If its from VAG they are some of the worst.  The engine rad, ac condenser and intercoolers all go pop at just over 3 years on a Porsche  

1 hour ago, Botus said:

interesting post, I bet the ones that failed have the later design of condenser made out of tin foil, where one winter's salt wasn't washed off because its not a daily driver or a bad winter with salt in use for many weeks.  If its from VAG they are some of the worst.  The engine rad, ac condenser and intercoolers all go pop at just over 3 years on a Porsche  

I haven't got Porsche money!

As said, the AC in my Mk6 Golf works perfectly...  As it did in one of the Mk4s.  It didn't in the other mk4 though, almost identical cars, same age and mileage even.

The Vectra C had the AC repaired under warranty at 2 years old, and was broken again time I bought it at 5 years old.

The Mk3 Focus is notorious for AC leaks, no idea why as most of the parts seem to be the same as the Mk2.  That had only done 42k/5 years though, at least the Vec had done over 100k.

The weirdest one is Mums Swift though, she bought it brand new so we know it's been run every day...

You should run once a month just to keep the oil in the system on the seals to keep them from drying out and reduce the leaks  Just 10-15 minutes should.do, and you lose roughly 10% of the refrigerant gas in annually. 

After reading this thread, yesterday I put the AC on with climate control, normally I leave AC off and just have the heater on, today I have a cold/flu and sore throat. Coincidence, or as a northerner is my body adapted to constant damp air and is reacting to the dry warm AC 😂

 

40 minutes ago, Mark-UK said:

After reading this thread, yesterday I put the AC on with climate control, normally I leave AC off and just have the heater on, today I have a cold/flu and sore throat. Coincidence, or as a northerner is my body adapted to constant damp air and is reacting to the dry warm AC 😂

 

Well colds and flu are caused by viruses...so hopefully there are none of those in your AC system!  More likely you were in contact with 'people' in the last few days, I'd recommend avoiding those at all costs, especially those extra small ones that are everywhere this week!  

 

i have a 62 plate 2.0 tdci with climate.   i leave it all all year round.  i do lots of londkn to yorkshire driving and to be honest it makes no difference to my mpg at all being left on.  still get between 55 and 61 mpg depending on road conditions.

7 minutes ago, michaelburrows said:

i have a 62 plate 2.0 tdci with climate.   i leave it all all year round.  i do lots of londkn to yorkshire driving and to be honest it makes no difference to my mpg at all being left on.  still get between 55 and 61 mpg depending on road conditions.

You are just showing off now! LOL I'm speaking as someone with a lowly 1.6 LX who celebrates whenever I manage to scrape 35mpg!

43 minutes ago, StephenFord said:

You are just showing off now! LOL I'm speaking as someone with a lowly 1.6 LX who celebrates whenever I manage to scrape 35mpg!

It's his long journeys doing that, even in a 1.6 I reckon you'd get 45mpg+ driving London to Yorkshire!

I think this thread has shown something interesting about AC though...those doing long drives and big mileages don't seem to notice it...  Those of us doing low mileage & regular short drives do...  

 

Also, in response to your earlier post about not using it when it's cold outside, it's just a precaution really, I've never heard of anyone actually breaking their AC by using it when cold.  It's the same with fridges & freezers though, they're not supposed to be used below about 16c, yet loads of people have them in garages!!

10 minutes ago, TomsFocus said:

I think this thread has shown something interesting about AC though...those doing long drives and big mileages don't seem to notice it...  Those of us doing low mileage & regular short drives do...  

I think that sums it up pretty well. I don't do mega mileage, as I once did,  nowadays, but I do try very hard to avoid using the car for short journeys especially in traffic.

I started the thread hoping for a clear consensus!!

tbh in 2 1/2 years I’ll hand the car back.  Was an argument with a friend I was hoping to settle.   He’s an on all year way of thinking. I only ever used air con when it’s really hot weather. Advise with my Vauxhall’s was turn it on a few times thru winter. I didn’t do that one year with a 2002 vectra ..next summer it didn’t work.

I’m keeping an eye on the mpg , in a few days should have an idea if it’s a noticeable difference. 

I switched off my air con yesterday and did exactly the same drive to work and back as normal and got extra 5mpg so yes, it does use about 8%more fuel with it on. But got  another 3 mpg improvement today as I had 1 less adult in the car today. So in my case I put aircon on and compensate by  not giving lift to my 2 work mates. Lol 

I've kept mine on the last few days due to the very wet weather and its kept my windows nice n clear