Automotive Air Conditioning Information Forum

tldr; Can I drive without any refrigerant in my Sanden 508 a/c system? Just for about 15-20 minutes I expect, between my house and the garage where they will fill it up.

Long version:

So I live in Morocco and if you send you car to the mechanic here, they fix the problem and break two other things so I tend to try and do vehicle work myself. I have an old LR Defender and I've bought one of those cheap Chinese universal a/c kits for it. I'm installing it all myself but it's got a belt driven Sanden 508 compressor and I'm wondering how I should get it to the mechanic so they can fill it up. I'm pretty sure it already has oil in it but I'll check that before I drive it anywhere. I expect the drive to the mechanic to get it filled up will be about 15-20 minutes at the most. Is this safe-ish to do or will it completely destroy it? The alternative is that I drive it to the mechanic and fit the compressor myself when I arrive but that will mean removing the viscous fan and changing the belt and everything right there, and I'll probably end up with 10 Moroccans trying to help me. It's lovely how helpful they are but it's a bit awkward when I don't speak Arabic/Darija and my French isn't great.

Do you have a High Pressure Cut-Off and/or a Low Pressure Cut-Off switch (or a binary or trinary switch) installed? If the answer is yes, you can safely drive the vehicle regardless of whether the A/C system is turned on or off because the compressor won't engage anyway if the refrigerant is low or the system is empty of refrigerant, as in this instance.

However, definitely DO pour-out any oil that the compressor came with and add back the specific amount and grade (usually PAG-46) of fresh oil that the manufacturer of the kit or the compressor recommend—guessing, usually around 8 fluid ounces.

Is R-134a readily available in your country or must you use an alternative refrigerant?

Thanks, I’ll definitely find out more about the oil and refrigerant. I don’t know if that one’s available here but I expect it is.

I did some digging around when you mentioned the cut-off switch. I’ve found it does apparently have one but I’m struggling to figure it out. I read somewhere else that it’s likely to be on the drier (accumulator?) and after I pulled a cap off I found two electrical spade type connectors, which I’m guessing may be either side of a pressure switch. On the diagram I have they’ve got a bunch of cables leading to the drier but nothing clarifying which side they should be connecting to, plus they’re all the same colour (green).

On the condenser there’s just one cable, a black one, so I assumed that would be a ground connection. On the diagram it also leads to the drier so I’m now wondering if this is actually a positive from the pressure switch to enable to condenser.

I can upload some pictures when I get home.

Twinnie wrote: ↑Sat May 18, 2024 5:47 am I did some digging around when you mentioned the cut-off switch. I’ve found it does apparently have one but I’m struggling to figure it out. I read somewhere else that it’s likely to be on the drier (accumulator?) and after I pulled a cap off I found two electrical spade type connectors, which I’m guessing may be either side of a pressure switch. On the diagram I have they’ve got a bunch of cables leading to the drier but nothing clarifying which side they should be connecting to, plus they’re all the same colour (green).

If the switch is on the receiver/dryer, then it's usually a binary switch on the high-side of the system that's designed to open at about 404 PSI (very high pressure), and also to open at about 25 PSI (very low pressure). If the wires are all the same color, then it doesn't matter to which side of the switch they connect.