kicker

2000 E320, wasn't put out enough freon, So I put in a can of LEAK STOP and a can of 12oz R134a Freon. Passenger side now gets cold but on the driver side is still warm?? what is happening? I know I might a leak since I put in one can back in April. I am hoping the LEAK STOP will fix the problem. Is there an AC calibration command I can use to re-cal AC, just cannot figured out why passenger is cold not driver side.
thanks

lexrex

You didn't put in enough R134a. Whenever you're moderately low, the passenger side will blow cool air and the driver's side will blow warm. You'll probably also hear hissing from the center vents.

Add more R134a until your evap temperature drops below 40 degrees and/or the hissing fades away. (You can watch your evaporator temperature using the climate control diagnostics; see search the forum archives for instructions)

sosh

Never use any leak stop stuff. You may already have done damage to the compressor and/or the receiver dryer. If one side is hot and the other cold you may have a flappervalve problem or perhaps a left thermostat problem.

kicker

My center vent did have this hissing noise. May be it really needs more Freon. I only put in 1 can about 12oz, probably not enough. I'll buy another can see if this would help. I wonder how many oz freon does the AC hold?

kicker

hi, thanks for the reply, do you know why the leak stop is bad? why would it damge the compressor. The stuff I put in is about 4oz, it got mixtures of red dye and freon. made by Castrol brand. the guy in the shop said it will fix the o-ring leak. then I put in another can of R134a. I guess may be it just wasn't enough. not sure though. will find out after I put in another can. My A/C before was just blowing warm air.

lexrex

Fixing the leak with a replacement part is better than using leak stopper. But leak stoppers are used commonly in gas pipelines to seal leaks, and they work as advertised with leaks that hold charge longer than about 2 weeks.

The leak stoppers react with moisture in the air around the source of the leak to seal the hole. The leak stoppers will not screw up your compressor (unless your compressor is the source of the leak and letting in moisture...in which case it's already bad!)

The only place a leak stop agent could mess up your system is the receiver-drier, which collects the trace amounts of moisture from your system. Sosh's concern is that the leak stopper will react with the moisture in the receiver-drier and clog it. The receiver-drier should not contain enough moisture to cause a problem. And if it does clog, the receiver-drier is one of the least expensive parts in the whole system... It's cheaper to replace that than a leaky evaporator!

If you heard hissing, I'm confident that your problem is low refrigerant, not a flap problem or stuck heater duovalve. But just to be sure, run the climate control diagnostics and list the values here for sensors #1 to #8.

lexrex

The system holds 1 kg, about 35 oz. Because our cars use variable displacement compressors, there's no way to determine the charge based on the refrigerant pressure. To do this correctly, you have to empty the entire system, measure it, and refill, but that's probably not necessary. I would fill until the hissing disappears or the evap temperature drops to under 40 degrees.

kicker

Lexrex,
On the way home today I turned on the AC it was blowing warm air, even on the passenger side, it's not cold any more. I add the freon and the leak stop on Saturday. I was gonna stop by auto place to get another can of freon, but I am puzzling now why passenger side is not cold.
Here is the reading for ac diag. after I ate dinner went to the garage.\
temp set to 72 on both pass and driver side:

1=94
2=85
3=102
4=100
5=100
6=184
7=07
8=89
9=32
10=4.0
11=2.3
12=4.3
20=3.2
21=4.2
22=00
23=32
24=13.3
40=164
41=85
42=40
43=136

Please advise, now center vent will make the hissing sound again.

dave

RobertG

If your a/c system has a sight glass you can use it to determine if the system is low on 134a.Bubbles in the sight glass indicates low ,add 134a in small amounts till bubbles diminish.

lexrex

RobertG, Does the W210 have a sight glass? I wasn't aware that it did.

kicker, the numbers tell me that either your refrigerant is low or your compressor isn't turning on. Since you hear hissing from the center vents but no cold air when you turn on the A/C, then your compressor is working.

Your evaporator temp sensor (a common W210 problem) works fine. Your duovolve looks fine.

You said the leak stopper had red marker dye. Have you checked for the leak visually? Since the leak stopper didn't stop the leak, it's likely that your compressor shaft is the culprit.

kicker

How would I repair cmpressor shaft? is that a DIY job? does not mean I have change the compressor? is the shaft attached to that. I coundn't see. Yes, my center vent still makes the hissing sound as of this morning.
I couldn't see any leak visually, I checked the dryer bottle, didn't see any leakage. I don't know if I should add another can of freon since the passenger side was not cold compared to Saturday.

thanks for your time.

lexrex

I'm just speculating that it's the compressor shaft. Could be something else entirely, but the compressor shaft is one of the things a leak stopper cannot fix.

Do you smell freon inside the car? If not, your evaporator is probably okay. It's possible that your A/C condenser (in front of the radiator) leaks, but I'd expect the leak stop to fix that.

My compressor shaft leaked. The system held charge for about 3 weeks or so before it all leaked out. If the shaft seals are bad, the whole compressor has to be replaced to fix the problem. A rebuilt compressor costs about $600. Any time you open up the system (e.g. replacing the compressor), the receiver-drier must be replaced too.

If it's not clear where the problem is, I'd take it to a good independent Mercedes mechanic rather than attempting this all DIY.

kicker

Lexrex,

Looks like we try to compete each other on the posting I am at 177 you are at 178. Ha.. we are now even at 178.

any way I'll try to find a independant dealer see what is going on. because if the freon holds, my passenger should be still cold too like Saturday. I'll start making some calls now.

thanks,
Dave

RobertG

I'm not 100% sure but i thought i saw the sight glass by the reciever dryer, it might not be facing the way to see it better , you might need a little mirror