AC problem with c300 - MBWorld.org Forums

Jun 30, 2012 | 07:24 PM

The Lover

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Mercedes Benz C300 sold , Passat CC 2010 Quad Exhaust sold , Mercedes Benz C63 2009

AC problem with c300

Hey

I have an issue with the air conditioner in my c300 2009

Recently I changed the AC compressor & Radiator , and put gas and everything

first day the AC worked fine , second day it worked for couple of hours then it only hot air comes and couple of hours later it worked normally .

Since 3 days now it stopped working and when i use the AC it only gives me hot air , like I am in Sauna !!!

I took my car to some shops and none of them knew the problem , checked with Xentry and it showed the gas is ok and AC is working ( fooling me :>( )

Any one please had this issue before or have some experience with this

Thanks

Jun 30, 2012 | 07:28 PM

tasho3

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From: Westmont, IL

2014 C63 Sedan

Quote:

Originally Posted by The Lover

I had something similar and took it in to find out some temperature sensor behind the engine was unplugged.

Jun 30, 2012 | 08:02 PM

The Lover

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Mercedes Benz C300 sold , Passat CC 2010 Quad Exhaust sold , Mercedes Benz C63 2009

the temperature sensor is installed and it's working normally , also i have installed a new sensor as a try to fix it , nothing changed

Jun 30, 2012 | 08:40 PM

MBRedux

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Nissan GT-R BE / '12 Ducati-1199 Panigale S / '12 C300-4M Loaded/GLK350-4M Loaded

This is basic AC 101. After you charged it, (I'm assuming you did this correctly by pumping out the system first and also making sure there were no pinhole leaks anywhere) did you:

1) Make sure you charged the system with the correct volume of refrigerant listed under the hood?

2) Separately added the MB recommended type of compressor lubricant? (If pre-mixed, you made sure it was compatible?)

3) You checked to see if your evaporator was freezing up on the second day? (When it worked fine then started to blow hot air?)

Based on these symptoms you either A) Undercharged the system. B) Did everything correctly but failed to check for small leaks. Thus, as the R134a charge leaked out, the system started to slowly fail once again. ( Working Great... then working ok, then blowing hot air (freeze-up then nothing as the charge detector solenoid shuts down the compressor to protect it.)

BOTTOM LINE: You have a bad leak. I wouldn't try stop-leak either. These quick fixes ruin the system, which will then be super expensive. Do a vacuum/partial-charge, only this time add dye to the system. Drive it for a day then use a black light to detect the leak. Replace what's leaking, and recharge the system. It should work flawlessly.

BTW: Make sure the lubricant is MB approved or compatible. Good luck..

Jun 30, 2012 | 09:03 PM

The Lover

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Mercedes Benz C300 sold , Passat CC 2010 Quad Exhaust sold , Mercedes Benz C63 2009

Thanks for answering my question
I didn't not do the work by my self , a took my car to a shop and they changed the Compressor and the evaporator and added the refrigerant .

and everything is new but as what I think is the problem is I have low or no compressor lubricant . it's just a guess leak issue since I changed all parts i mentioned above

Thanks

but please could you explain what you mean by A) Undercharged the system

because I don't think I have

Jun 30, 2012 | 11:50 PM

MBRedux

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Nissan GT-R BE / '12 Ducati-1199 Panigale S / '12 C300-4M Loaded/GLK350-4M Loaded

Quote:

Originally Posted by The Lover

The amount of refrigerant is very important. Over charge (too much) will either blow a seal, ruin the compressor or both. Under charge (too little) will get you some cool air for awhile, but it often causes the EVAPORATOR to freeze up, especially on hot humid days. (This is located inside the dash, and is NOT to be confused with the condenser, which is in front of your radiator.) This ice prevents air flow over the coils which in turn causes even more freeze up which again chokes off the air flow!... a vicious cycle until you get nothing but warm to hot air.

However, there are at least 12 or more rubber "O" ring seals throughout the system. Just because some guy replaced the compressor and probably your condenser (and not the evaporator as you claim) doesn't mean the system is leak-free!

You have a small leak, that's my best guess, and until it is found and properly repaired, you will be wasting your time and money, and possibly blowing your new compressor. Get the dye, vacuum-out the system using a good grade pump, (at least 30 min.) charge it again with R134a and the proper lube amount and a small can of Luminance Dye. (They sell R134a with the dye built in.) Run it for a day or so, then use a black-lite (at night) to see where the leak is. It will glow a brite green/blue. Replace the leaking "O" ring(s) or the faulty component, recharge AGAIN and you should be good to go.

Go to Harbor-Freight Tools (there's one near you no doubt and buy the proper tools and do it yourself.) Link: http://www.harborfreight.com/25-cfm-...ump-98076.html

Pump