GeriatricGinger

Was out running errands with my wife. We stopped to have lunch. Got back in, started the GLK, and no cold air. Blower works fine, etc. When I got home, I checked with my AC gauges. 75F ambient, the low side was about 68psi, High side about 100. I hear no cycling of the AC compressor, and the system will not take any freon (134a).

anyone have any experience with this issue? No idea why it worked fine, then 30 minutes later, no longer cooling the air..

2011 GLK350, 97k miles

GeriatricGinger

Update:
Using my $200 Actron, I showed NO codes stored.. Using my friend's VERUS D10, there were 16 random codes stored in the GLK. None of them were anything remotely AC-related. So after fiddling with it for awhile, I cleared all the codes, and restarted the car..

The AC started working.. The oddity is, that when you turn off the ac (push AC button, LED goes out) the AC remains on.. I now have to hit OFF, then hit FAN, if I only want the fan to blow without the cold.Even the VERUS Scanner shows ac remains in ON state, until I hit the OFF button.. weird..

GeriatricGinger

welp, this issue reared it's ugly head again. Same issue: AC gauge shows 70psi on low side, turning on AC makes no change. System will not take R134a. Fan kicks on when you depress the AC button. All fuses are fine. I guess I'll try to see if my friend can scan it again with his Verus D10 scanner, since (once again) my Actron shows no codes.
Any thoughts or suggestions are appreciated.

ItalianJoe1

The refrigerant control valve in the compressor is failing from the sound of it. MB fix is to replace the compressor, but the valve can be purchased from outside sources and replaced. It is on the compressor and will require the system to be recovered and recharged, but that was the issue almost every time with an intermittent or delayed cooling issue on German cars.

GeriatricGinger

Thank you very much for your response. I'll look to see if I can find the part. I have an evac system access, so I'm good there. Just need to figure out what part I'm actually looking for. I was confused when I looked at the 'clutch' and it wasn't there.. LOL Then read that it was a 'clutchless'.

GeriatricGinger

is this what you're referring to?

ItalianJoe1

Yep, exactly like that. Held in by a small snap ring on the compressor itself. Simple to change once you drain the system.

I often found debris lodged in the screen down by the valve, which would explain yours being stuck "on". I'd bet you could clean it and re-install and it would work fine, although the valves are usually under $50 so I would just change it while I'm in there. I'm not sure if you can get to it on that platform, I have done some VW ones where I don't have to remove anything, it was facing down and I just removed it and recharged the system, super easy. On Rover/Jag products at my current job, I usually have to unbolt the compressor and rotate it in situ to gain access to the valve, it faces the engine block. MB was always a complete compressor replacement so I don't recall the position of the valve.

GeriatricGinger

Thanks, again! I'll prolly just get a new one, as I'd hate to go through that and clean the old one, only to find out I get to do it again when cleaning it didn't work. lol
No AC in this charcoal-colored shoebox with black leather, leads to a very unhappy wife
I'll order the part today, and let you know results, once I get it all back together.

Side note: Do you have have any suggestions on possibly a decent scanner for the DIYer, that will actually read stuff worthwhile on an MB? My Actron is near worthless on the Benz..

ItalianJoe1

Invest in one of the clone SDS systems, they are more than a cheap scanner but still only a couple hundred bucks and will do anything factory level that doesn't require online connection, which is plenty for any DIY or shop use.

GeriatricGinger

pardon my ignorance, but do you have some 'example' scanners that come to mind? I don't mind spending a couple hundred, if it's worthwhile.


EDIT: Ordered XC10606C "BMW Mercedes A/C Compressor Control Valve", $43.

ItalianJoe1

Contact the user Pmercury on here, he knows more about the systems that are available than most, he will be able to give you the most good info on the clone systems. I have never looked into one personally, I worked at MB and could still go there if I really needed a scanner as a couple friends are still in the shop, but a local shop owner/friend bought one, and had to get a specific laptop and hard drive to make it work, was a bit to set up, but worked well once it was running. I'm not the most computer savvy person.

GeriatricGinger

Thank you. My new control valve should arrive today, so if I get a chance this weekend, I'll try to swap it out and post results.

GeriatricGinger

@ItalianJoe1 I cannot thank you enough, sir. Well, maybe if you'd driven up here for some killer homemade, brisket, ribs, and wrenchin' with me...
But at any rate, Alldata said 3.3hrs.. LOL not for this fatboy.. More like 10. haha.So apparently theres a HUGE difference between the W204 and X204 4Matic cradles.. I could not use hardly a single socket.. 3 bolts for the AC, I had to use a 10mm ratchet wrench and pray I didn't strip the e12 bolts.. that was GRUELING..

But, I swapped the compressor control valve EX10606C was the part I used. Once it was all back together, I pulled a vacuum for about 20 mins, then locked it down at -20inHg. Let it sit for about an hour, and it stayed right there. Threw a couple cans in it and with ambient around 78-80F, I got it down to 58F at the vents. But it needs more, I think.. Low side was around 38, and high side was about 115.

Thanks again!

ItalianJoe1

That's not very strong pressure, should see the low side below 30 and the high side 150-180 depending on your ambient temps. I've not charged a system from cans in a long time, always by weight, but seeing the pressures that low I'd def add a bit more. Should see 40 degree vent temps at 80 degree ambient.

andreigbs

Correct, ze German autos definitely rely on the correct weight of the refrigerant. This is because the system can pressurize as needed based on the load, the desired temp setting, ambient temps info from various sensors and so on.

There should be a sticker somewhere under the hood that says the correct weight +/- a certain number. Go by that when filling a completely empty system.