Air Con Not Working

[Robboc180]

Hi all A\C was working fine last year when one day i noticed bright green fluid (Trace Dye) on the floor under my car (1995 C180), I looked inside the bonnet and noticed it was coming from the sight glass on the Dryer. As summer was over i never go it done until now i purchased a new Dryer from Ebay and installed it myself, got the car re-gassed yesterday technician said pressure was low and not enough to get the system cold and says the A\C compressor pump has gone is this a correct diagnosis. Any had a simalar problem and knows a cure like compressor needing oil???

Thanks.

 

[Andy Wr]

If pressure was low I presume that was after the system was dehydrated down to at least 4 mbar and the correct amount of gas was weighed in using accurate scales or charging station.

The pressure would then only be low if the gas was leaking out as fast as it was been put in but a nitrogen pressure test would of proved this before the guy recharged the system which he surely did, or there is a blockage in the system usually in the liquid line, now as you have replaced the drier are you sure that it is the correct one and that all the blanking plugs had been removed from it prior to fitting and I presume it was a new drier not a second hand one as they are a sponge for moisture.

 

[Robboc180]

Yes Dryer was advertised with part number and it matched mine, Part was new all blanking plugs were taken out. I also had to take out the electrical plug from the old one and put this in the new one is this correct???

 

[Andy Wr]

Sounds correct, was the guy recharging the system experienced in this type of work and did he put the right amount of gas in the system?

If there is a blockage by removing the outlet pipe from the filter drier, placing your finger on the now open port on the drier, put oxygen free nitrogen through the low side of the system nitrogen should now be evident under pressure where your finger is blanking the drier off, possibly lifted your finger, the open pipe which was on the drier should have a steady tickle of nitrogen coming through and if you blank it with your finger the pressure should build up, this would prove a system is clear and is a good way to blow out contaminants from the system.

Before doing any of the above the system HAS to firstly have the gas in the system removed in an environmentally friendly manner and only oxygen free nitrogen can be used to purge the system, it is illegal to use gas.

 

[Robboc180]

Hi Andy quite right on your diagnosis, it was a blockage a had to bleeded out.
All working fine now.
Thanks for advice.

 

[Andy Wr]

You are very welcome, we are all here to learn from one and another about our pride and joys.

 

[lance@lanceuk.com]

Air Con not working C270 cdi estate 2002 HELP!

Can anyone give me some good advice.

My C270 has been smellling of deisel fumes in the car for some time and now that summer is here we realised that the air con is not working.

I had a air con service done at a good local garage they drained and recharged the system using a new Bosch machine all was well - no leaks but the fluid was down some degree.

When it was recharged the Air con compressor still did not work.

I rebooked the car in today for an electrician to look at - guess what he couldnt sort it and the message is - TAKE IT TO MERCEDES.

Mercedes have quoted me £928 plus vat for a Air con service and compressor replacement.

I am just about to sell the car and cant afford this kind of bill.

The other garage said maybe there is a reset on the compressor but that mercedes wont tell them.

Any Ideas???

Or any one know a good Aircon company in the Oxford area who would be cheaper.

HELP!!!!

Lance

 

[Andy Wr]

I think you need to take it to an independant who can plug it to check the fault codes, a quick way to test the system is to disconnect the 12 volt feed to the magnetic clutch and hook up a fused temporary lead from the battery to the magnetic clutch when the engine is running of course, you should hear a click as the clutch energises and if there is gas in the system the system should start cooling, if it does this means that it is an electrical or electronic problem, maybe even a reset on the star diagnostics but check your AC fuse first though.

There are a few checks that can be performed but it is always difficult in advising as we do not not how far to go as in a recent post by Malcolm.

 

[lance@lanceuk.com]

c270 cdi air con compressor problems

I think you need to take it to an independant who can plug it to check the fault codes, a quick way to test the system is to disconnect the 12 volt feed to the magnetic clutch and hook up a fused temporary lead from the battery to the magnetic clutch when the engine is running of course, you should hear a click as the clutch energises and if there is gas in the system the system should start cooling, if it does this means that it is an electrical or electronic problem, maybe even a reset on the star diagnostics but check your AC fuse first though.

There are a few checks that can be performed but it is always difficult in advising as we do not not how far to go as in a recent post by Malcolm.

Thanks for your reply.

UPdate - Apparently the compressor does not have the electro magnetic clutch type mechanism.

The test showed two fault codes B15BO and B15CO power getting to unit but not working, the electrician cant find out what the codes mean. Any ideas?

 

[Andy Wr]

Thanks for your reply.

UPdate - Apparently the compressor does not have the electro magnetic clutch type mechanism.

The test showed two fault codes B15BO and B15CO power getting to unit but not working, the electrician cant find out what the codes mean. Any ideas?

I will have the codes in my autodata book but I dont have it with me today, regarding the magnetic clutch, I would be intrigued to know how it engages then?

 

[Andy Wr]

The test showed two fault codes B15BO and B15CO power getting to unit but not working, the electrician cant find out what the codes mean. Any ideas?

I can not find any listings for those fault codes, normally it would be B followed by 4 digits.

What year is your car, if it has the automatic temperature control with a digital screen, self diagnosis can be carried out.

 

[eric242340]

I can not find any listings for those fault codes, normally it would be B followed by 4 digits.

What year is your car, if it has the automatic temperature control with a digital screen, self diagnosis can be carried out.

I think the year is important here as later models dont have the magnetic clutch, as i am sure Andy understands.

 

[kebo57]

Hi my ml 270 2001 has magnetic clutch on a/c you con see this operate from above the compressor, there is a pully at the front of it, (you no this just trying to help) anyway there is two parts to the pully sort of front disc and the drive pully where the belt fits there is a gap between these to items about 0.5 mm you can see light through the gap if you look closely when the clutch is not engaged, no gap when engaged as for the insides of the compressor I can't add any more
Kevin

 

[Jack Sprat]

Hi my 2001 C270 also has the magnetic clutch and this too has failed. <68K miles. Cheltenham Radiators claim to be selling the MB part at £434 inc. I understand from a dealer they are £670 inc. If you find better Lance shout!

 

[hmang]

Hi my 2001 C270 also has the magnetic clutch and this too has failed. <68K miles. Cheltenham Radiators claim to be selling the MB part at £434 inc. I understand from a dealer they are £670 inc. If you find better Lance shout!

talk to mercman in southampton
i bought a clutch off a knackered pump for £60

still got it too.....didn't need it after all....live and learn !

 

[hmang]

I think the year is important here as later models dont have the magnetic clutch, as i am sure Andy understands.

can you explain this one for me eric as i'm keen to understand too.
ta.

 

[eric242340]

can you explain this one for me eric as i'm keen to understand too.
ta.

Happy to. The electro magnetic clutch type have an alluminium plate on the front, however the none electro looks like a normal pulley and is black at the front. The changeover varies from model to model and is not only affected by year, but by the month in that year. But you can tell just by looking at the compressor. Both types work on the signal sent (by the pressure sensor located on the dryer), but with the new model there is not clutch and therefore fewer working parts to worry about. Please dont ask me to explain how the new one works, I would have to write a book.

 

[wscheffer]

Checking Air Conditioner Compressor Clutches

... a quick way to test the system is to disconnect the 12 volt feed to the magnetic clutch and hook up a fused temporary lead from the battery to the magnetic clutch when the engine is running of course, you should hear a click as the clutch energises and if there is gas in the system the system should start cooling, if it does this means that it is an electrical or electronic problem, maybe even a reset on the star diagnostics but check your AC fuse first though.

There are a few checks that can be performed but it is always difficult in advising as we do not not how far to go as in a recent post by Malcolm.

A quicker was to see if the clutch on the compressor is working or not is to turn your key to the #2 position and with the engine not running disconnect the voltage side of the pressure switch located on the dehydrator. You will hear the clutches engage and disengage rapidly.

 

[Jack Sprat]

talk to mercman in southampton
i bought a clutch off a knackered pump for £60

still got it too.....didn't need it after all....live and learn !

How do I get in touch with mercman, member or Google? £60 a great alternative!

 

[JARushby]

Hi

I have a similar problem with my C220 CDI. Aircon simply not working. Had it re-gassed and leak tested. No problem there. EC light goes out so no problem there. However, compressor simply does not engage. I managed to physically lock the compressor to the flywheel so the compressor was definitely turning (just a temp measure to ensure compressor was ok). cold air streamed out. So, it would appear there is an electricl problem or a problem with teh magnetic clutch.

I have tried to wire a positive lead from battery to teh magnetic clutch but appear to be getting strange results. Before I wired the temp feed I measured the voltage and it seemed to show ~8v irrespective of whether the EC buttom was pressed or not. I was expecting 0v or 12v. When I wired the temp feed from the battery I could hear a light "click" when I connected the feed to teh battery but still the clutch did not engage.

My diagnosis would normally be the the magnetic clutch was in some way faulty but to be honest I am not sure that I was connecting into the correct wire. I assumed that the positive feed to teh mag clutch was the single lead that has a connector that sits on top of the air con compressor. Is this correct. the lead simply seems to connect there but there does not seem to be any obvious connection to the mag clutch. can someone please advise where the feed to be mag clutch actually is.