Air con replacing refrigerant?
Just a general question really, for discussion - why is it that car aircon systems are recommended to be re-filled every couple of years? I mean, your average fridge or freezer runs quite normally for maybe 20 without it?
Is it the more extreme use/environment or a car system or something else? Kwikfit say that 10% of the refigerant 'permeates out' every year? How and why? Is this an older car issue only?
Also, what are the indications that it is needed? Plus I saw an ad for replenishment with R134 refigerant or something - is that the best option?
It just seems like a scam to get your car in the shop, because if the gas is leaking through worn seals, then just replacing the or topping up the gas is like filling a tyre with a puncture.... the garage will try to get you for new seals and anything else it can see? (a little side Google just showed this to happen sometimes, and £45 can sometimes sting you for £400 !) .
Hi
older vehicles " like G wagons"aircon used "Freon 12" which is now considered to be environment non -friendly and a banned substance ..R134 is considered by many best for mobile applications .converting involves purging,possibly some seals and charging...not a DIY job...to avoid problems the aircon system should be run at least twice a month to aid lubrication/serviceability..obviously with a mobile system there is greater tendency for leaks to develop..systems left un-charged for long periods can absorb moisture and require purging before re-gassing....weather appears to affect the re -commissioning costs!! much cheaper getting the job done in the middle of winter
The main reason for servicing a/c systems every 2 years is to replace the receiver drier. This is a filter fitted in the system to absorb moisture and debris from the gas, and problems arise when this filter breaks down, filling the system with the silica gel beads it contains to do its job. This can be costly, flushing pipes and valves isn't always succesful and new ones often have to be fitted, let alone the possible damage to the compressor. A service would include recovering the gas, a process which would filter it for re-use, replacement of the receiver drier, pressure testing, vacuuming the system and re-gassing, as well as cleaning the condenser/evaporator/air intake filters etc, checking and tensioning drive belts. Not a 5 minute job, and not a job that can be done properly for £45! But still cheaper than letting it all go wrong. On the subject of gas type, R12 is now no longer available, R134a is the norm, and converting from R12 to R134a involves a service as described above, plus removing the compressor and changing the oil, flushing the pipework etc, or simply use an additive with the old oil as some do, plus fitting the new type service ports. Vehicle systems are subjected to extreme temperatures, ie, hoses etc in the engine bay, as well as vibration, causing seals to harden, pipes to crack etc, hence them being slightly unreliable. Air conditioning service is something I do as part of my agricultural machinery repair business. Hope this helps, regards Mick.
The main reason for regassing an old type R12 system is that the refrigerant gas is a chloroflourocarbon if you combine that with small quantities of water (moist air sucked in through a cracked seal for example) you end up adding the CL to your H2O and get HCL hydrochloric acid...thats what accelerates the rot and can mess with your seals and cause a bigger leak and eventual system failure.
Its good practice to get it looked at about once every 18 months vacuating the system and pulling a vacuum on it wiull cause all the contaminats to evaporate away and prevent problems occuring
In an R12 system the oil is mineral based and should last the life of the car but on a newer R134 system the PAG oil will eventually dissapate and be lost so its important to replenish from time to time.
with both systems as usual I think its just a case of spending a little money now to save a big repair bill later
JOIN THE GWOA
This website and forum are provided for the benefit of enthusiasts and owners of all Mercedes Benz off road vehicles, in particular the G Wagen. The costs of development, upkeep and provision of the site are met entirely by the annual subscriptions of club members. If you are using the site and are not a member of the G Wagen Owners Association please consider joining. You will have access to areas on the site that are not open to non members, to club trips and meetings and to technical assistance. In addition your contribution (only £25 annually) will help us maintain and develop our website for future users.
Who's new
- Jaffa_JIM_23
- Wrabstar
- GG
- KTMSCANIA22
- 280ge
Yes that's all really good info and much more involved that I thought. I bet most AC owners have NEVER had them serviced though, and I bet that dealer services don't touch it either (even MB ?).
It was an academic question for my G, whose AC is an open window - sounds much more servicable but the AC in my A-Class was never good from new and takes ages to cool the car. I think its just an under-designed unit.