W202 Air Con revival

[charlysays]

Hi all,
really wasn't sure where to post this.
Summers seem to be getting hotter and my car is black which has got me thinking about trying to revive the aircon on my C250 TD.
It hasn't worked for years...
My partners cars air con has just stopped working so we're going to re-gas it with a kit from halfords. There will be plenty left over or should be to re-gas my merc too.
Is it worth going somewhere to get the system vacuum tested first?
What is likely to have died in the aircon system from lack of use?

I'm fairly handy with DIY stuff and tackle most jobs on the car including chipping it and extensively modifying the fuel system etc so I'm happy to tackle it myself but I've never done anything with aircon before so wondering what the best plan of attack is

Thanks in advance

 

[denchen]

I always take mine to a reputable place to get mine charged if I think it's not doing as it should. A good firm will empty the system, then charge it with a pressure, leave it a while to see if the pressure drops then recharge it with the right amount of lubrication and gas. If you simply add to your system, you are not sure if you have a leak and there's no way of knowing how much refringent is already in the system. My small local garage does mine as and when. They are just a local garage, not MB approved or specialist, although they do have 2 ex MB mechanics. Prices might be a bit more than say Halfords, but they have a good reputation and want to keep it. 'But you pays your money....'

 

[Mr Greedy]

Most likely the condenser (radiator) on the front, but if it's been unused for a long time, there could now be loads of other issues. Moisture into the compressor causing corrosion will goose the compressor. Rubber seals are kept in good condition because the oil in the system is continuously circulating and lubricating them. On my old Alfa, the aircon pipe going to the condenser/compressor ran right next to the exhaust manifold by design, so those used to rupture with good regularity (I don't know about on the w202). If it's not integrated within a new radiator, you would also need a new receiver/dryer, as the one in the car will probably now be saturated due to moist air ingress.

If you were serious about wanting this, and not wanting to chase rabbits down holes for the next 12 months, I would consider taking it to some sort of aircon retrofitting specialist, and see if you can get a 'new' system installed (assuming parts availability for the w202 system is non-existent/eye wateringly expensive.

Regassing a system with a leak is a criminal offence btw.

 

[M80]

The machines that carry out the vacuum test aren't replicating the working conditions. A nitrogen pressure test would be far better.

I would do that 1st to identify leaks.
Then it is more than reasonable to replace the compressor at least. The dried out seals are likely to pass. the lack of lubrication could well mean it will seize soon after reviving the system, mine did.

 

[mioba]

The last 2 paragraphs of Mr Greedy. I agree.

 

[charlysays]

Most likely the condenser (radiator) on the front, but if it's been unused for a long time, there could now be loads of other issues. Moisture into the compressor causing corrosion will goose the compressor. Rubber seals are kept in good condition because the oil in the system is continuously circulating and lubricating them. On my old Alfa, the aircon pipe going to the condenser/compressor ran right next to the exhaust manifold by design, so those used to rupture with good regularity (I don't know about on the w202). If it's not integrated within a new radiator, you would also need a new receiver/dryer, as the one in the car will probably now be saturated due to moist air ingress.

If you were serious about wanting this, and not wanting to chase rabbits down holes for the next 12 months, I would consider taking it to some sort of aircon retrofitting specialist, and see if you can get a 'new' system installed (assuming parts availability for the w202 system is non-existent/eye wateringly expensive.

Regassing a system with a leak is a criminal offence btw.

The parts all seem to be available on autodoc... prices start at 180 for the compressor, dryer about 30 and condenser 70-80. So 300 quid ish in parts to replace the most likely goosed bits doesn't seem too bad.
Is there any way to inspect the existing bits on the offchance they aren't knackered?

I looked up the legislation on re-gassing aircon systems and it only mentions the law being relevant to service providers but clearly it's mad not to test for leaks if they are strongly suspected whether you're a member of the public or a service provider.

"

Servicing and repairing of air conditioning systems​

3.—(1) No service provider may fill an air conditioning system with fluorinated greenhouse gases where—

(a)an abnormal amount of refrigerant has leaked from that system, and

(b)the necessary repair to the system has not been completed.
"

 

[rifiki]

When you do get the ACs working have the AC on all the time, summer and winter.
With a bit of luck will have no more problems.
The AC on my 05 CLK has never been re-gassed or had repairs.