I just discover this problem within a month. My AC is running well when the weather is cool, but not blowing cold air out in hot days. So if it’s below 70 F outside, it works well, you can feel the cold air coming out. But it doesn’t work if it’s hot outside. For the last couple days it was 90 F something out here, my AC is just blowing the hot air into my face .

I have the AC recharge today, clean the blower filter, but it does the same thing. It seems first blow cold air for like 30 seconds then the warm air . The blower works ok just doesn't blow the cold air.

Thanks in advance for any suggestion

 

Unfortunately, it could be any of a number of things. Fortunately, if you go to this website, and then list the codes again in this thread, you may get help.

 

Thank you Marcus,

Will try that!

 

So my freon pressure sensor. #7 reads between 7-8 at all times. when the car is off. when ac is off. when ac is on. and when i revved the car a bit it stayed right between 7-8. hopefully if i add a little freon i will be gettting ice cold air again. Its kinda cold when its on..but nothing like it was when i first bought the car. Im going to buy r134 and put it in and let you guys know how it goes!

 

So i just got back from autozone with ice cold ac!!! im so stoked that was so easy. My reading on #7 is now right at 16! with cold air blowin. that was so easy!! for anyone that thinks they need to take there car to a shop for a simple recharge they are crazy! I bought the can of freon for 20 bucks with gauge and plugged it right in with car running. and bam! ice cold ac!!!

 

Can you take some photos of where and how to plug in the can ?

thanks

 

Do you still have the problem??? Have you checked that your twin fans are coming on??? I had the same problem, and it was the relay.... Worked when it was not so hot then failed as the outside temp went up....

 

Hi, where is the relay located on a CLK W208? Thanks.

 

low pressure connect located mid engine on drivers side. You will see the connect covered by what looks like a tire valve stem cover. It just pulls off (no thread). The kit that is sold is so easy to use (clamp hose to can, turn crank to pierce can, close valve, hook other end to low pressure of A/C and reopen valve at can). Keep the engine and A/C running and watch the can. It will get frosty and as it enters the system, the air will get cold from your vents. I know that I'll get slammed doing this by feel but it has worked for me as long as I have had a car.
ps..just be sure that you are on the low pressure side and that you don't tip the can upside down.

 

Typically, the valve on the high pressure side is bigger than the valve on the low pressure side. The fittings that come with the can of R134 will not fit on the high pressure side--will only fit onto the low pressure side valve.

 

Thanks guys. I figured that the low was the one mid engine and not by the rad but for some reason, I thought that the one by the rad was another low port. Thanks for the clarification.

I recharged my AC about 2 summers ago and it worked perfectly fine until about 2 weeks ago. I thought that maybe I just needed to refill it again. When I went to do that I noticed that the AC clutch was not even moving, so, even though I had the recharge kit connected to the Low side port, no Freon was entering as the AC system was not turning on.

I read something about a relay for the AC. Is that where I should start?
Thanks.

 

Hi Marcus - I printed out your page and have been trying to solve my own A/C issue all summer, which I thought at first was low freon, but a recharge hasn't really fixed it. I posted about it here, including diagnostics: https://mbworld.org/forums/clk-class...lve-issue.html

Another resource for A/C diagnostics that i discovered can be found at this link: www.eclassbenz.com. It's for the W210 but I believe it's the same HVAC system and will still apply. The guy only asks that you "buy him a beer" by clicking on a link

 

I posted in that thread. I think its the evap sensor.