Leak in the AC system

[Macau_C180]

Hi,

When i buy my car, the old owner replaced the AC pump with a brand new one, but after 2 weeks, no more cold, we both take the car to the shop where they replace the pump, and they checked it for leaks, and didnt find any in the engine compartment, so they say it might be under the dash. I know that to replace the coil under the dash is a lot of work involved as the dash must completely be removed.

Any other place i might check for leaks before going for the dash removal?

thanks

 

[grober]

The heat exchanger/ condenser at the front of the car beside the radiator is often subject to road debris damage or corrosion so worth checking. Get the system recharged with refrigerant with a fluorescent marker dye in it and run it for a few days. Any visible leak/leaks should be apparent as little beads of congealed dye. Assuming you have a W202 180 C class here are the parts involved.
http://www.detali.ru/cat/oem_mb2.as...417717.418&CT=F&cat=44V&SID=83&SGR=195&SGN=06

 

[Macau_C180]

Hi,

Thanks for your reply. Last week i already refill the system and also put in that fluorescent marker dye in, and now is starting to have little cold, so i guess i have a big leak there. Gonna check it one of this days, i just hope is not in the coil under the dash

 

[Andy W]

It will be the condenser, if there was no gas in the system to start with the guy was wrong to just charge it up to see how long it will last, he should of found the leak regardless of how long it took by using all means that are available, nitrogen, ultrasonic, electronic, bubble aerosol and even fairy liquid, dye is only used to find small nuisance leaks, good leak testing procedure finds leaks 99% of the time. If I had just recharged a commercial system and the powers at be found out, I would be prosecuted.


A general rule of thumb used in the trade, if there is still at least 50% of the gas charge remaining in the system, you have a small leak such as o rings or compressor seals, if there is no gas in the system you have a major leak that can not be recharged such as a rubbed through pipe or hose or a rotted condenser unless it is identified and repaired first, the exception to the no gas in system rule is if the system has been previously decommissioned prior to removing the engine and the person who had the decommissioning work carried out will have a waste transfer document prepared which you can inspect.

 

[Glenn Smith]

i agree it will be the condensor, you may have to pul the condensor away from the rad and look between the two, dirt etc. collects here and causes corrosion, if you find a quiet spot you may be able to her the gas hissing out.

 

[Macau_C180]

Hi guys, well another garage tested my system with some machine that can "smell" for the R134, and it started bipping like crazy when he put the sensor in the air vents in the dash....

So the leak its in that part thats under the dash, i dont know the name for it, its the thing that actually gets cold where the fan blows ......

Very hard to replace as the dash must be completely removed

 

[Andy W]

That will be the evaporator, they do leak occasionally but also some cheap electronic leak detectors can give false reading if you send air down the sensor or even blow down it, if it is leaking that badly nitrogen will make the leak present it self itself by making a hissing noise, I prefer to visibally see a leak, to actually pin point it.

 

[Macau_C180]

Well in this case, if the leak is really from the evaporator, then the only way to "see" the leak is to remove it, and for that, the dash needs to come out