Adding Freon
replenishing r134 can result in damage if you're not certain how to perform
this properly....and whether your A/C really need the juice. first, quickly
read up on the following (you should have simlilar diagnostics, yes?)
go to this link and read magazine article on A/C
go here and read diagnostics
then go here and perform diagnostics
to the right of the yellow warning sticker is metal line. this is the low
pressure A/C. in the middle you can see black fitting. this is threaded
cap. unscrew and you'll see a valve fitting which kinda resembles the
schrader tire valve (but isn't). this is where r134a hose fitting is to be
connected. but again (!).....don't do this w/o first reading up on the
links above.
pic from engine bay of 99 E320 V6.....
If the pressure gauge is measuring something dirrerent, what should the value be?
What should the refrigerant temperature be (test #8). Does it also rise and fall with the amount of freon in the system.
Can I just add freon until the pressure and temperature read in the recommended range?
Thanks
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Pressure varies according to load in a perfectly operating system.Just got back from a 2700 mile road trip,went up the grapevine in Ca. at 70mph a/c on cabin temp at 64f on an 88f afternoon,pressure varied from 7-16 value.The Benz system varies with load.
post those values,
ohlord
"GOT CODES?"
The Best of Mercedes & AMG
You can also use soapy water to check for leaks or electronic leak detector depending on your budget.
No failed sensors....find and fix the leak.Failed sensors,fix them first.
don't worry about sun sensor code.
ohlord
"GOT CODES?"
I would add that after you've done all the steps above...you'll need to clear the EC light by resetting the climate control computer. I posted this the other day in a thread...if you search, you shall find.
ohlord

"GOT CODES?"
1. 91
2. 84
3. 84
4. 91
5. 89
6. 184
7. 7
6. 94
Didn't seem like the freon went in to me. Still had quite a bit of pressure when I unhooked.
Should the 134A can be upright or upside down? Should I be running the A/C when adding freon?
EC light is now off and all codes cleared. None came back when I re-ran them, but the A/C is still warm.
ohlord

"GOT CODES?"
Last edited by ohlord; Aug 15, 2007 at 08:13 PM.
ohlord

"GOT CODES?"
1. 80
2. 76
3. 84
4. 84
5. 84
6. 184
7. 6
6. 82
Anybody got any ideas? A/C still blows warm. EC light is off.
Seems that you are low if those codes for error still show,and since you can't tell how much low on the mb variable load system,you may have to get the charge pulled,evacuated and recharged.If r134a is not going in you drier or some line may be blocked.Post the error codes again,and then the next step may,and I say this reluctantly ,find a good indie a/c shop.
ohlord

"GOT CODES?"

Really should not be to big of a bill if they know what they are doing,and since you pull the codes and errors,at least you have an idea of what to look out for.Have you ran the tests with the engine running and set the climate controls to 60f on both sides and write down the values?The beauty of the onboard diagnostics is that you can set at any temp and watch the values as it operates.Run them with the engine warmed up to 195f,and record them and then shut it down and run the error test procedure,and record that.The compressor is operating,r134a is low,everything seems to be in order,It can't be more then labor and 134a plus some oil and a new drier.
Maybe you wont need the chef hat!
ohlord
"GOT CODES?"







