Going to recharge my AC...

[panzerwagen]

I had paid big bucks several years ago to change over to 134. Now after what I think is 2 years, it needs a recharge. It seems every 2 years I have to re-charge the system. I've asked several pro's on this and they all say that 134 does not last as long as R12 and that 134 has a tendency to escape through the hoses due to it's smaller molecules. One guy told me to change my hoses to the "Captive Type".
Here's my question...Where is the "Low-Side" orifice on the car? On the Compressor?
I'm going to use the Twin-pak Recharge kits with a dye that are sold at local parts stores. All you do is screw on the cans to the low-side nipple and go. If there is a leak the dye will tell you. But I've had mine tested several times and no leaks have ever been found.

[S2central.net]

Yep - low side port on the compressor...

[panzerwagen]

Thanks Paul...not looking forward to this.

Have you ever tried this...recharging it yourself?

[S2central.net]

Nope - mine leaks too quick - has always needed a proper repair - never bothered to sort it.

I've notice the AC on our other car getting a bit weaker of late - and have been tempted to try one of those recharge kits - its the same brand of stuff we get here now that I used to see on the AC isles in US carparts places. Its a fairly recent addition to UK stores actually. My only concern is not really knowing how much gas is being put in - all you have is the generic pressure guage on the tin.

You can get real nice cheap pressure guages in the states too for aircon - I got a set, but never used them yet (D'oh).

[s2driveruk]

i thought the bottle had the guage on them anyway? @scratch: yep was also told 134 gets out of R12 systems quickly too, thats why i went down the rs24 route.......having said that mine now seems to have a leak

[lini]

Nothing can show a leak that holds gas inside for two years. Forget it. Wait until it leaks realy bad shorter than a season and then you go for a proper recarge. With that recarge put the paint inside (special one for aircon leak searching). recharging aircon without a proper vacum (30mins at least) doesnt make any sense. Vacum makes all the water go out of the system and it takes all other gases that are slowly building in the system. Charging the system without knowing the ammount of gas put in the system is bad. Reason is that 0,750kg of gas in the system makes at 20degrees 6bar and at 35degs 10bar and at the hot engine 15bar. The problem is that on a hot summer day your aircon system will shot down in a periodical manner due to to high presure caused by too much gas and high temps.

And one more interesting info. I ˝converted˝ R12 system to r134a only by changing the seals and oil in the compresor for a proper one and ofcourse making a fitting to charge it. This system works for 2years and about 50.000kms. It works absoloutley without problem. To get back to recharge: Recharge it properly, tell the guy who does it to put the paint in and then after a week or so check the system with equipement for searching for leaks (glases and UV light).

My opinion is if it holds for two years dont bother with it.

[panzerwagen]

I'm going to use this product...

http://www.jcwhitney.com/autoparts/S...&zmap=ZX360278

It has a gauge and leak-sealer. It automatically shuts down when system is filled.

[UUUdirs2newcastle]

The lads at Mercedes Benz workshop were going to re charge mine, but they could not get the lower nipple off the compressor. can I buy a new nipple? It seems that it is just unscrewing off the unit, rather than the aluminium screw cap coming off!

[johne]

The lads at Mercedes Benz workshop were going to re charge mine, but they could not get the lower nipple off the compressor. can I buy a new nipple? It seems that it is just unscrewing off the unit, rather than the aluminium screw cap coming off!

If your compressor is like mine then the connector on the compressor isn't a standard low side A/C quick connect but a screw thread one that is difficult to use. The "official" low side A/C connector is on the evaporator tucked up behind the ECU in the passenger footwell.

I suggest you get the boys at the Merc workshop to recharge your system through the high side port on the condensor (in front of the water radiator). Most of the automated recharge systems garages have these days can cope with just using the high side port - just don't run the compressor during the process!

John

[johne]

I had paid big bucks several years ago to change over to 134. Now after what I think is 2 years, it needs a recharge. It seems every 2 years I have to re-charge the system. I've asked several pro's on this and they all say that 134 does not last as long as R12 and that 134 has a tendency to escape through the hoses due to it's smaller molecules. One guy told me to change my hoses to the "Captive Type".
Here's my question...Where is the "Low-Side" orifice on the car? On the Compressor?
I'm going to use the Twin-pak Recharge kits with a dye that are sold at local parts stores. All you do is screw on the cans to the low-side nipple and go. If there is a leak the dye will tell you. But I've had mine tested several times and no leaks have ever been found.

It is true that R134a is more prone to leak than R12 so the spec for the flexi hoses in a R134a system is higher than for a R12 one - However, it turns out that the mineral oil used to lubricate a R12 system tends to seal the inside of the pipes and that sealing isn't lost if you just empty the system and convert to R134a.

So, if you've got an old R12 system there's no need and no point in paying big money to have it "converted". Just buy a connector adaptor kit, drain it and have it refilled with R134a.

John

[johne]

http://www.jcwhitney.com/autoparts/S...&zmap=ZX360278

It has a gauge and leak-sealer. It automatically shuts down when system is filled.

That kit is a rip-off. It's very difficult, if not impossible to recharge accurately using a pressure gauge to determine how much gas to put in. You should recharge by weight of gas (well actually liquid) that goes in. Then you can use pressure gauges on the high and low side (which is where the gauges you have Paul come in) to see if the system is working correctly for the ambient temperature at the time.

However, for those of you lucky enough to be in the US, there is an easier way. You can go down to your local Wal Mart, Pep Boys, Krachen Auto etc. and buy tins of R134a for $8 a tin. It takes 3 tins to fill our cars. If your A/C still works but just isn't cold enough, put one tin in. If your A/C won't work because the low pressure switch won't close, i.e. you've got less than 45 psi of pressure with the system off, put two tins in. If your system is empty, refill with three tins - but if your system is absolutely empty then a vacuum suck out and reoil is recommended to get any water and old contaminents out.

Those of us in the UK could do the same if you can find tins of R134a for a reasonable price. If your paying Halfrauds price for tins, it's better value to find a garage who'll do a recharge for £50 for you.

John

[johne]

Nothing can show a leak that holds gas inside for two years. Forget it. Wait until it leaks realy bad shorter than a season and then you go for a proper recarge. With that recarge put the paint inside (special one for aircon leak searching). recharging aircon without a proper vacum (30mins at least) doesnt make any sense. Vacum makes all the water go out of the system and it takes all other gases that are slowly building in the system. Charging the system without knowing the ammount of gas put in the system is bad. Reason is that 0,750kg of gas in the system makes at 20degrees 6bar and at 35degs 10bar and at the hot engine 15bar. The problem is that on a hot summer day your aircon system will shot down in a periodical manner due to to high presure caused by too much gas and high temps.

And one more interesting info. I ˝converted˝ R12 system to r134a only by changing the seals and oil in the compresor for a proper one and ofcourse making a fitting to charge it. This system works for 2years and about 50.000kms. It works absoloutley without problem. To get back to recharge: Recharge it properly, tell the guy who does it to put the paint in and then after a week or so check the system with equipement for searching for leaks (glases and UV light).

My opinion is if it holds for two years dont bother with it.

The biggest cuase of problems with A/C is NOT using it. I don't know how to do it but I'd like a huge post at the beginning of the A/C section of this site telling folks to "Use it or loose it " as far as their A/C is concerned. It's not for nothing that manufacturers have been putting notices in their cars handbooks for years telling you to run the A/C for 15 mins. at least once a month

In my opinion the reason younger cars have A/C that appears to last better is that these days many of them are linked to climate control systems that use the A/C all the year round without the owner realising. To stop an A/C system leaking you have to keep the seals - particularly the compressor shaft seal lubricated and that lubrication only happens if the system is being used.

I have to look after a '94 Saab and a '94 Range Rover, both with A/C. Both of them have only ever had one 250 gram top-up in their whole lives.

John

[S2central.net]

John - you are the AC king !

So I have this old V6 with R12 - its not working, but the only fault the HVAC controller throws up is to do with lower battery voltage than it would like - no errors about low gas pressure.
Anyway - I would like to convert it to R134 (or RS24). Some questions then -

1. Do I need to change all the seals ?

2. Do I need to change the restrictor (I think not) ?

And can you confirm that I need to do the following during the conversion process ---

1. Replace the drier/reciever/reservoir

2. Drain / evacuate all traces of old gas and oil

3. Charge system with PAG oil as compatible with R134 gas

Finally though - the 1st thing I need to do is have the thing leak tested before I do anything - I have one of those leak test kits from interdynamics with the dye, lamp & goggles - are they OK for use on R12 and R134 systems ?

Oh last question (D'oh) - Anything special I should look out for when hooking up my AC pressure guages onto this system - other than maybe funky LP port on the compressor ?

Cheers,

Paul

[panzerwagen]

John should be made moderator for this forum!

John, question....I have a 1990 CQ. And the guys who did the conversion put a 134 low side nipple there. Reading one of your earlier postings you said that the real "Low-Side' IS IN THE PASSENGER FOOTWELL...what car would that be?

[s2driveruk]

Paul, for £60 I'd get someone to do it for you, they can vacuum down the circuit and ensure it is airtight as when they did my conversion to rs24 he did that for 30mins at 200mb to ensure it was worth trying to recharge it.