300sl-24 (91) air con re-gas

[Unsound Methods]

hello all.
i bought myself an STP regas kit for my 2003 jaguar xj and have succesfully recharged my air con system, running nice and cold.

i thought i'd give the r129 the same treatment. found the valve but the STP valve wont fit the car , its too big so i cant get a seal to recharge.

at first i thought mercedes might have made their own valve - just to be really helpful - but as im writing this i wonder i ive actually used the correct valve!
there are 2 ports visible on the Jaguar - right next to each other - so i located the low pressure port and refilled in seconds.

Would my car - 1991 300sl-24 have 2 ports that are not located next to each other? or is there just the 1 below the air filter housing?

cheers
dani

 

[Unsound Methods]

right, so i found a Few threads online and although i havent found images / details of my own engine bay, i think i should have 2 ports.... time for another look see.........

 

[Unsound Methods]

found it, i think.
still doesnt fit. i think the kit i have has a quick lock/release thing, rather than one that screws on to the port. i think maybe i need one that screws on..

bugger

 

[Tony Dyson]

Maybe it's a refrigerant gas compatibility issue? have you checked?

 

[Unsound Methods]

good point, i didnt realise the gun itself would be different depending on what refrigerant was needed. i guess that would make sense though.
i have the "STP Air-Con Reusable Trigger and Gauge - For Gas R134A"
i'll try and find out/double check what refrigerant gas i need for the merc.

 

[rayhennig]

If your system has never been upgraded, as mine (300CE24) hadn't in 2017, then it probably contains R12 (Freon) refrigerant.

I'm no expert in this but you may have either to upgrade the system or find some R12 replacement as R12 is now illegal and cannot be supplied.

But don't take my word for it.

RayH

 

[Uncle Benz]

If it still has threaded connections it’s on the old r12. Its easy to upgrade to r134a with a simple kit of two connectors

 

[Unsound Methods]

thanks gents. it has threaded connections. i'll see if i can find the kit you've mentioned UB. cheers

 

[Richard Moakes]

Needs a bit more than just adapters on the service ports

New receiver dryer, new high pressure switch, POE oil rather than PAG, which will be in the can.

Please take it to a professional, it will be cheaper in the long run, and by professional, I don’t mean someone with a wheelie bin tool, I mean someone who really knows what they are doing.

 

[Unsound Methods]

Needs a bit more than just adapters on the service ports

New receiver dryer, new high pressure switch, POE oil rather than PAG, which will be in the can.

Please take it to a professional, it will be cheaper in the long run, and by professional, I don’t mean someone with a wheelie bin tool, I mean someone who really knows what they are doing.

Ive just been reading about the other bits that will need replacing richard. I am going to speak to my indie first when it goes in for some work in a couple of weeks.. thanks for your input.

 

[Uncle Benz]

Needs a bit more than just adapters on the service ports

New receiver dryer, new high pressure switch, POE oil rather than PAG, which will be in the can.

Please take it to a professional, it will be cheaper in the long run, and by professional, I don’t mean someone with a wheelie bin tool, I mean someone who really knows what they are doing.

You can go factory method if you want to. It becomes uneconomical pretty quickly though. I have converted a lot of systems with a decent flush and recharge with ten percent less refrigerant. Most of the cars I’ve converted are still working perfectly ten years plus on. If you have unlimited budget, new dryer, new orifice tube, replace all rubber seals, new compressor if there is any doubt about it’s ability to handle the higher pressures. You can very quickly get into four figures with this. It can be done on a budget quite successfully. I’m not sure where the “wheelie bin” reference comes from? You need to have training and a certificate to work on air conditioning systems these days. I have one.

 

[Richard Moakes]

The OP, was going to use a can of R134a with PAG oil, just adding adapters and using that would be a recipe for disaster, leading to additional expense later down the line.

PAG and mineral oil, do not mix, and as you say, the system should be flushed
Adding gas by pressure will lead to overcharge, it needs to be done by weight
If the system has been open to air, it needs a vacuum to boil off the moisture, and a new dryer unit

I could go on, I am fully aware of F gas certification, and I suspect we both know the pitfalls of converting with a can of refrigerant from Halfords etc.

By wheelie bin, I mean an automated machine at places like Kwik Fit, operated by people who don’t know what they are really doing. Those machines are fine, if the operator has been prop trained and not given 10 mins overview like they get at certain fast fit chains.

 

[Garista]

Interesting stuff, thank you all. I just installed a digital inverter on my house and was thinking about the car air con, but maybe better not... I don't know, I so like to do everything myself.