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Earlier cars had a superheat switch, later ones had a pressure switch. If the freon pressure was low the pressure switch would prevent the clutch from engaging to preserve the compressor. The superheat switch melted if the freon temperature got high from low freon. It doesn't work as well as a pressure switch and has to be replaced if it trips. A pressure switch doesn't need to be replaced. If a compressor fails and seizes, then there are bits of metal spread throughout the entire AC system. Basically you have to replace everything the freon touched at that point. A very major and expensive job.
Ok that makes sense... I read something about fuses and wasn’t sure exactly if that’s what they really meant. I think if I had bits of metal throughout the system I would just never touch it ha. I want to get some Freon in this sucker and hope the compressor is good! Then I won’t have to worry about 90 degree Midwest summers anymore.
Ok that makes sense... I read something about fuses and wasn’t sure exactly if that’s what they really meant.
Here's a pic of the 3-prong 'thermal limiter' fuse as used with the 'superheat switch' systems. If you have one it'll be attached to the compressor bracket.....or sometimes dangling by the wires nearby.
Systems using the HSLP switch----High Side, Low Pressure.---- did not have the thermal limiter fuse.
As far as I know none of the Jags with the Mark III climate control used the thermal limiter fuse....but I can't swear to it.
Here's a pic of the 3-prong 'thermal limiter' fuse as used with the 'superheat switch' systems. If you have one it'll be attached to the compressor bracket.....or sometimes dangling by the wires nearby.
Systems using the HSLP switch----High Side, Low Pressure.---- did not have the thermal limiter fuse.
As far as I know none of the Jags with the Mark III climate control used the thermal limiter fuse....but I can't swear to it.
Cheers
DD
ahh so it is almost fuse-like. Interesting I’ll have a look today
I wouldn't bother with R12 until you're 100% certain the system is leak free by it holding vacuum. I'd probably use R134 in the meantime anyway.
yeah R12 isn’t a good long term solution anyway as it’s getting rarer and rarer. I know the r12 disappeared from mine but the car sat in a barn for like 8yrs. I imagine no matter what the car and system a gas would eventually escape or evaporate?
It's just a matter of having good seals. I have had an XJR that had perfect AC and was 23 years old and was the factory charge.
So basically it’s a matter of getting out the mineral oil that is left, changing the fittings and o-rings? Or can I just add esteroil that I’ve read is compatible with r12 and r134? I guess for $16 this cheap vacuum will get anything out...
I'm not sure about the oil. The XJR I had was factory fill with R134.
You'd have to completely take apart the system and flush each component to change the oil, it's a difficult task. You should be able to simple put on the adapter ports and change with R134 and you're good to go. Assuming they system is actually leak free. You'll need the good vac pump and proper gauge manifold to know that.
I would get a real vacuum pump, not an air one like that. You'd need a very large compressor to run that and I hear they are not very good at generating a deep vacuum.
I'm not sure about the oil. The XJR I had was factory fill with R134.
You'd have to completely take apart the system and flush each component to change the oil, it's a difficult task. You should be able to simple put on the adapter ports and change with R134 and you're good to go. Assuming they system is actually leak free. You'll need the good vac pump and proper gauge manifold to know that.
I would get a real vacuum pump, not an air one like that. You'd need a very large compressor to run that and I hear they are not very good at generating a deep vacuum.
everything else leaks on the car maybe the mineral oil did too. Haha
BTW, venting any remaining R12 into the atmosphere is illegal, not to mention irresponsible. It's supposed to be collected. If you don't have the equipment to do it, take it to someone who does.
A cheap vacuum pump is not a collection system.
If you must have something R12 compatible, look at Freeze 12, which is at least less damaging to the ozone layer.
BTW, venting any remaining R12 into the atmosphere is illegal, not to mention irresponsible. It's supposed to be collected. If you don't have the equipment to do it, take it to someone who does.
A cheap vacuum pump is not a collection system.
If you must have something R12 compatible, look at Freeze 12, which is at least less damaging to the ozone layer.
oh yeah I know... like I said there’s nothing in the system. It sat for so long
