FAQ's and Hints and Tips

Here are several Questions that have been "Frequently Asked" which can relate to other similar models. There is a much more comprehensive section on information for AC at the bottom of this page.

The majority of questions I am asked by email refer to badly functioning or non-functioning AC systems. There are also some questions from owners who would like to "do it themselves" and need a little guidance but in Europe since 2010 it is not legally possible to interfere in any way with the refrigerant without the appropriate qualification even if you have the correct equipment, leaving only the electronic control of the AC circuit or the physical mounting of the components which the owner can tackle. To be honest the disposable cans of R134a refrigerant are not really good news for owners of modern European or Far Eastern cars as most of these run with variable displacement compressors unlike the majority of American cars which still use much simpler fixed capacity compressors. So even if you are happy to ignore the UK law it is not a straightforward matter to try to top up an AC system.

Here are a few questions that have been asked over the past couple of years where part of an answer may prove useful to other owners. I do try to answer all emails that come through (sometimes well into the twilight hours) but this section may save me answering some of the most common questions.

Question 1. - The owners manual of my previous car said to regas every 2 years. I recently read a website which said the AC needs regassing every year and the receiver drier changed each time as well. What are your recommendations for my '56 plate Laguna 2.2 DCI?

Answer - I'll tell you what I think but I'll also tell you what I do with our own vehicles. I have always said that vehicles should be recharged no later than 4 years from new and then every 3 years thereafter. Some cars introduced in the past 6 or 7 years though would seem to require recharging a little more frequently - say after no longer than 3 years from new and then every two and a half years thereafter.

Replacement of the drier. Your Laguna does not have a receiver drier, it has an accumulator which is the drier type used on the suction side of the AC circuit but the principle is still the same. I'm sure that some other AC technicians might disagree with me but in our experience we have found that except in certain circumstances (replacement of a component, a leak in the system or evidence of a previous accident repair to the front of a vehicle) except in these circumstances we see no benefit in replacing a drier until it is 7 or more years old. I have to say that the theory is to replace more frequently - this is just my observations over some years. Our own previous VW Golf which was recharged every three years and finally had the drier changed at eleven years old - no other AC work or part has had to be changed since new and yet the car has driven to the Mediterranean every summer with perfect cooling.

Now let me tell you what we do with our own vehicles. In 2000 we bought a second hand commercial vehicle which was 2 years old. The climate control seemed perfect but to be absolutely certain we recharged it. Over the next five years we recharged this HGV three more times at approximately 20 month intervals, partly as Planned Maintenance and partly to ensure that our driver was always comfortable. When the vehicle was sold the climate control was still going well, even after 746,000 km. Yes, you did read that correctly - that's three quarters of a million kilometres. Nothing had been changed on the AC system, not even the drier. Another example - our own car a 2001 VW Golf, again bought second hand, is now fifteen years old. It was recharged in 2008 and the AC was fine to the south of France in 2009 and the Costa Dorada in Spain in 2010. We never had time to recharge it before we drove down to the Costa Dorada again in 2011 but it still performed perfectly. It was recharged again in 2012 and the drier was also changed as the drier was well past its sell-by date. In early 2015 this Golf was evacuated and recharged again. Without regular recharges, acids produced by moisture in the system might well have eaten through the condenser by this time. I will be very surprised if this should occur in practice - planned maintenance (a good recharge) at regular intervals helps to ensure a long healthy life for AC. We have finally decided to update to a later model Golf but the AC on our 2001 car is still performing perfectly.

Question 2. - My 2002 Galaxy TDI has been recharged each spring in the past two years but has failed again this spring. Presumably there is a leak in the AC system somewhere but the garage found no leaks, or so they said.

Answer - The Galaxy/Alhambra/Sharan range use virtually identical components for the AC system on the diesel models and many other closely related parts on the petrol models. Your car certainly sounds as though it has had an undetected leak for three years. It is just possible that it could be one or more electrical faults but my best guess is a longterm leak. This is not that uncommon. Surprisingly even main dealers seem to be missing the leak that is the most common and which appears almost always in precisely the same spot. If your garage has not been able to detect this almost certain leak, use an AC specialist who should be using a better standard of detection tools.

Question 3. - I had my Volvo V70 recharged as it was not working properly. It seems to work really well when I first turn it on but then after 10 or 15 minutes the car heats up and I get no cooling until the car has been turned off for an hour or more.

Answer - Almost certainly the problem is wear on the AC compressor clutch. This sounds dramatically expensive but is usually fairly easily cured as the clutch face has one or more thin shims to keep the adjustment correct. These simply need removing and replacing with thinner shims to adjust the clutch gap again.

Question 4. - My 2002 Toyota Prius is used mostly for short journeys and I rarely use the AC. I have been told that this might make the gas escape more quickly. Is this so?

Answer - For almost every car this would be true but for the later cars with Hybrid drive, as the Prius has of course, this is not really the case. In fact the AC may have been used a lot more frequently than you think. This is because Hybrids have a battery pack for the electric traction motor. This battery pack is horrendously expensive. To achieve a reasonable working life this battery pack needs to be kept cool and when they are being either charged by the petrol engine or are being used for electric drive the traction batteries tend to heat up. The AC is automatically switched on at these times to cool the batteries down again. As the life of the battery is severely shortened by heat it is obvious that it would be very foolish to allow the AC to become less effective even if you may not wish to use it for your own comfort.

Question 5. - The AC compressor of my Audi A4 Diesel 2005 is making a slight noise but strangely only when the AC is turned off. I am convinced that it is the compressor but cannot understand why this should be when it is not actually working.

Answer - This compressor is one of the newer electronically controlled sort that are impossible to turn off. The ECON button appears to turn it off but it is in fact still rotating and is actually compressing refrigerant but at only about 2% capacity. Because of this it is important to keep this AC system charged as in theory these compressors would fail completely if there was insufficient gas to help circulate the lubricant. The car is now approximately 4 years old so is about due for a recharge. The probable low gas charge is hopefully responsible for the noise.

If none of these emails answered the problem you have encountered please have a look at the information website below. It is quite long so skim through to see if it covers the subject you wish to know more about, so may I point you to this website entirely devoted to information on aircon in cars. This site rambles on quite a bit but it answers many questions and there is loads of information on many aspects of this subject. There are no adverts or pop-ups to annoy you and there is a return link to bring you back to this site if you should wish to do so. If then you still do not have the information you need please email me from the contacts page with your query and I will endeavour to answer it.

So click on this link below for about 20 pages of information which may help you to run your system more effectively, to give you an insight into what is going on under the bonnet in the AC department and may also even allow a little self-diagnosis if your AC system is making funny noises or is not up to scratch. Although initially started many years ago, the occasional update and revision has ensured that it is still relatively relevant and I will try to ensure that it stays this way in the future.

Just information on car air conditioning, how it works, how to use it better, how to diagnose simple faults, petrol consumption when using AC, the environment and AC and a bit of a rant about some environmental issues.


The next page is about Fault Finding

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