A local dealer has a clean 95 4L Convertible with 55k, however the compressor doesn't run when you turn the AC on. The climate control panel lights up and appears to operate normally otherwise. What's a ball park figure on what it takes to get these old AC systems working properly??

Also, the convertible top cylinder appears to be leaking as well. Nice car otherwise.

 

Between $50 and $3000.

It depends on why the compressor isn't coming on.

Broken wire to clutch - ten minute fix - $50

Bad clutch - a few hundred

No refrigerant - most likely - if leak is in evaporator core, junk the car unless you want to spend several weeks replacing it yourself.

 

Yeah, as Darel describes, the possibilities are far reaching. Inoperative a/c might well mean dropping the car from the candidate list.....unless you're getting a real bargain price and/or can fix the problem yourself if it turns out to be serious.

Or.....


If all else is good, agree to buy the car a "xxx price" on the condition that the A/C be fully repaired before the sale is finalized. Chances are the dealer will say "no" becuase he, just like us, doesn't know if it'll be $100 or $3000 to repair.

Not that it's carved in granite but if it was an *easy fix* the seller, private or dealer, would have already had the repair done....as it's much easier to sell a car, and at a higher price, with functional a/c.

Cheers
DD

 

compressors dont run if theres not enough refrigerant in the system. its a safety feature that keeps them from burning up. the only way to know if thats the issue is to prime the system with about 20 oz of R134a.

checking the system for pressure with a ten dollar gauge is the easiest way to tell if it has no refrigerant.

 

I had them fill the system (it's 134a) and was told it worked but could have been colder. Not sure where that puts it. Admittingly A/C systems are my weakness it automobile knowledge.

 

well how much did they put in? if they only put 20oz in then itll barely kick on the compressor. a system like that needs about 36-48 ounces.

 

I was told they filled it up.

 

well if it works, but isnt very cold, thats usually because it doesnt have enough refrigerant. go look at it in a few days and if it doesnt blow out any cold air at all, that means it all leaked out.

 

Thanks for your help. I'll update when I know more.

 

Unless it's very different where you are don't let them all scare you.
Test if the refrigerant pressure is low by running the engine and briefly shorting the pressure switch on the compressor (with a/c switched on). If the clutch engages look at where the leaks are. If not it's the wiring or the clutch. The compressor is a big heavy ugly old Harrison unit widely used in the US.
I paid an 'expert' to fix mine. He charged it with R403 which turned out to be Butane based, totally incompatible and dangerous. The 'repair' lasted two days and I could see all the gas/oil bubbling out of the condenser. I charged it with a DIY can of R12 substitute and it worked for another few days so I knew where the fault was. During my work on the body I have also replaced the condenser which is widely available at reasonable cost, and the receiver/dryer and I'll pay someone do charge it with R134a. At the prices I can see there is no way that there is $3000 of equipment on the car and it's very easy to do most of the work yourself.

 

The $3000 is a worst case scenario type of thing if, let's say, the evaporator needs to be replaced....a labor intensive job....and assumes a repair shop doing the work, not DIY labor. A bit high perhaps but not entirely impossible.

It's true true that the parts are widely available and reasonably priced although I'll add that the 4.0L cars didn't use the old Harrison A6 compressor. Jaguar switched to somethng more modern...a Sanden, I think. Still, though, not particularly expensive.

If the problem boils down to simply identifying and replacing a single defective part it might not be too bad indeed. If there's a peculiar problem with the control side of the system I can envision an expensive repair bill.

The 4.0 convertibles are not rare. It shouldn't be hard to find one in great condition with working climate control. Personally, I'd rather go that route !

Cheers
DD

 

Where do you find a DIY can of R12 substitute?

 

I got my whole sytem redone for way less than 1K

OEM new (not rebuilt) Sanden Compressor for less than 300.00. Right from the Sandedn factory in Japan. No cheap reproduction

I sourced a drop in parallel flow condenser for around 250.00

Expansion valve ranges from 20.00 to about 200.00 depending on where you get in and the quality . I got an OEM from the UK for about 60.00'

A drier can go from 50.00 to 150.00...I go with the cheap ones here because I like to replace them often.

Hoses are like any other car.

The only thing that can get very costly is the evaporator, but there are guys running 78 XJS's converted to r134 with the evaporator as the only original part, so hopefully that is not the case with you


Good luck

 

you dont. you get a can of R134a and the conversion kit which consists of 1 fitting to accept the R134a hose.

 

I was hoping to use it for troubleshooting before I disassemble the system to convert. Don't yet know where my leak is. Found Freeze-12 online.

 

Don't waste money on the so called R12 replacements. R134a is what you want. it too will be phased out someday as it has a 0 ozone depletion rating but carries a 1300 global warming rating. That is a medium rating. There are new refrigerants on the horizon which will take the place of R134a.

Most of the R12 replacements are butane or propane based. Google them.

Why not pay a shop to charge it and diagnose you problem and then do the repairs your self and have them recharge it. if you are upfront with them they will be glad to take your money for not much work. The A/C charging is easy, the tools to do it properly are very expensive. You can have them add UV dye to the system. Then if you have a slow leak you can use a UV light to find it.

 

Because I have an aversion to ever paying a shop for anything. That'll probably be what I do.

 

If your system is empty just charge it with R134a. Then once you know what you need to do then you can do a proper conversion. The system will work fine and you won't hurt anything. The original refrigerant oil will be fine for operating the system in the short term while you diagnose. Short term as in a few weeks or months. Then once you start repairs drain the oil and measure it. Add in new PAG oil in the amount you removed plus and ounce. New receiver dryer and you are in business.

You are wasting money on that Freeze 12 stuff. It is 80% R134a anyway.

Composition of Refrigerant Blends | Alternatives / SNAP | US EPA

 

you dont have to take the system apart to convert it to R134a. it takes 1 fitting for the conversion.

 

To do a half assed conversion, yes. (This is what I suggest until he knows what is wrong with the system). If you want one that will last and be trouble free then you need to replace the oil. This entails draining the compressor and replacing the receiver-dryer. Also the o-rings should be changed too. Technically the hoses should be the barrier style to prevent ever so slight leakage. After a few years my system is still ice cold. Also it sounds like his system has been open to atmosphere which has rendered the desiccant useless.