AC blowing only heated air
Thread Starter
Member
Joined: Jun 2005
Posts: 86
Likes: 0
From: Miami, FL
2000 CLK 430 Coupe
AC blowing only heated air
Folks,
My apologies for the cross post, but hoping to resolve this quickly. The original thread is here https://mbworld.org/forums/mercedes-...ings-w208.html
I'm looking for advice in dealing with a problem with the AC in my 2000 CLK 430.
It is blowing only hot air, regardless of temp settings (from 62 all the way up), fan speed, and whether EC is engaged. The compressor, drier, and blower resistor were replaced 6 months ago. Other than an occasional thud when switching from recirculate to fresh air, everything has been working fine.
At this point, when switching between EC on and off, I hear a slight change in sound in the vents, but nothing apparent under the hood, and no drop in RPM.
Thanks for insight you have.
Regards,
e harmon
My apologies for the cross post, but hoping to resolve this quickly. The original thread is here https://mbworld.org/forums/mercedes-...ings-w208.html
I'm looking for advice in dealing with a problem with the AC in my 2000 CLK 430.
It is blowing only hot air, regardless of temp settings (from 62 all the way up), fan speed, and whether EC is engaged. The compressor, drier, and blower resistor were replaced 6 months ago. Other than an occasional thud when switching from recirculate to fresh air, everything has been working fine.
At this point, when switching between EC on and off, I hear a slight change in sound in the vents, but nothing apparent under the hood, and no drop in RPM.
Thanks for insight you have.
Regards,
e harmon
Thread Starter
Member
Joined: Jun 2005
Posts: 86
Likes: 0
From: Miami, FL
2000 CLK 430 Coupe
Thanks Mike.
I will see if I can confirm that is the case with my car too.
Some more info: the Auto light does not go out when I change the fan speed manually.
Also go these readings by using the REST button:
1: 86
2: 82 (79 with engine off)
3: 90
4: 89
5: 88
6: 174 (possibly climbing; 135 with engine off)
7: 0
8: 93
9: 0
10: 0.9
20: 0
21: 0.6
22: 0
23: 100
24: 14.3 (12.3 with engine off)
40: 8
41: 5
42: 200
43: 14
Also, now that the ambient temp is lower, I observed that the air does not appear to be heated, just not cooled. I'm guessing the summer day had me fooled earlier into thinking the air was heated.
Regards,
e harmon
I will see if I can confirm that is the case with my car too.
Some more info: the Auto light does not go out when I change the fan speed manually.
Also go these readings by using the REST button:
1: 86
2: 82 (79 with engine off)
3: 90
4: 89
5: 88
6: 174 (possibly climbing; 135 with engine off)
7: 0
8: 93
9: 0
10: 0.9
20: 0
21: 0.6
22: 0
23: 100
24: 14.3 (12.3 with engine off)
40: 8
41: 5
42: 200
43: 14
Also, now that the ambient temp is lower, I observed that the air does not appear to be heated, just not cooled. I'm guessing the summer day had me fooled earlier into thinking the air was heated.
Regards,
e harmon
Last edited by e harmon; Jun 7, 2010 at 11:27 PM. Reason: realized that the air was not being heated
MBWorld Fanatic!
Joined: Apr 2005
Posts: 3,784
Likes: 84
From: SCV SoCal
2002 CLK430
It’s 86 degrees in the car, and 82 outside the car.
Hot coolant is in both heater cores. We know that because both heater cores are hotter than the air in the car. At some point you’ll have to check the duovalve, but there is one major problem that stands out – number 7 is zero. That’s the Freon pressure. No pressure could mean the compressor hasn’t turned on, and that may be due to the system being empty. If it’s empty, you probably have a leak.
Hot coolant is in both heater cores. We know that because both heater cores are hotter than the air in the car. At some point you’ll have to check the duovalve, but there is one major problem that stands out – number 7 is zero. That’s the Freon pressure. No pressure could mean the compressor hasn’t turned on, and that may be due to the system being empty. If it’s empty, you probably have a leak.
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Joined: Feb 2008
Posts: 1,261
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From: SoCaL (LA / OC)
E55 AMG (SOLD), EvoSport CLK (SOLD), 2013 GsxR 750 (SOLD)
My A/C isn't cold at all too. unfortunately it just happened recently. but what does those numbers mean? kinda lost me there 
Also go these readings by using the REST button:
1: 86
2: 82 (79 with engine off)
3: 90
4: 89
5: 88
6: 174 (possibly climbing; 135 with engine off)
7: 0
8: 93
9: 0
10: 0.9
20: 0
21: 0.6
22: 0
23: 100
24: 14.3 (12.3 with engine off)
40: 8
41: 5
42: 200
43: 14
Regards,
e harmon
do you know where the A/C piping is located? I don't even know where to start. Last summer i paid over $500 at the dealer for... inspection / recharging the a/c / and connecting the loose tubing. i'm definitely not paying that kinda' money this time around.
Also go these readings by using the REST button:
1: 86
2: 82 (79 with engine off)
3: 90
4: 89
5: 88
6: 174 (possibly climbing; 135 with engine off)
7: 0
8: 93
9: 0
10: 0.9
20: 0
21: 0.6
22: 0
23: 100
24: 14.3 (12.3 with engine off)
40: 8
41: 5
42: 200
43: 14
Regards,
e harmon
do you know where the A/C piping is located? I don't even know where to start. Last summer i paid over $500 at the dealer for... inspection / recharging the a/c / and connecting the loose tubing. i'm definitely not paying that kinda' money this time around.
Thread Starter
Member
Joined: Jun 2005
Posts: 86
Likes: 0
From: Miami, FL
2000 CLK 430 Coupe
It’s 86 degrees in the car, and 82 outside the car.
Hot coolant is in both heater cores. We know that because both heater cores are hotter than the air in the car. At some point you’ll have to check the duovalve, but there is one major problem that stands out – number 7 is zero. That’s the Freon pressure. No pressure could mean the compressor hasn’t turned on, and that may be due to the system being empty. If it’s empty, you probably have a leak.
Hot coolant is in both heater cores. We know that because both heater cores are hotter than the air in the car. At some point you’ll have to check the duovalve, but there is one major problem that stands out – number 7 is zero. That’s the Freon pressure. No pressure could mean the compressor hasn’t turned on, and that may be due to the system being empty. If it’s empty, you probably have a leak.
Regards,
e harmon
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Junior Member
Joined: Mar 2010
Posts: 28
Likes: 0
From: Saint Paul, MN
CLK 430, SLK 230
Wouldn't these data all point to the problem simply being low levels of freon? You've probably developed a crack in one of your hoses that is allowing the freon to escape (happens frequently if you don't use your AC regularly to circulate through the system not only the freon but also the oil that is mixed in with it, which keeps the hoses and seals lubricated). If this is the case, go to an auto parts store, pick up a $5 can of 134A refrigerant and a dispenser with a pressure gauge, connect it to your AC port per the instruction found in this forum, and recharge the system. It takes maybe 10 minutes. I do it every spring and my AC stays ice cold all season. Good luck!
Rob
Rob
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Member
Joined: Feb 2008
Posts: 75
Likes: 3
From: Chandler, AZ
2001 C320, 1997 E320, 1993 300e & 2005 F150 Supercrew
E Harmon,
Try this trick, I call it my 99 cent fix. I did this to T/Shoot the problem I had in my CLK & E320...
Get a 1k ohm resistor (form radio shack or a local electronics store). find and pull out your evap temp switch. (underneath the drivers side).
Disconnect the evap sensor and place the 1k resistor in place of of the sensor.(it wont hurt your system.)
If your compressor kicks on and you start feeling cold air then the problem is your evap temp switch is bad.
If the compressor still doesn't kick on then you are probably low on freon and might have a leak.
Hope this helps
Rusty
Try this trick, I call it my 99 cent fix. I did this to T/Shoot the problem I had in my CLK & E320...
Get a 1k ohm resistor (form radio shack or a local electronics store). find and pull out your evap temp switch. (underneath the drivers side).
Disconnect the evap sensor and place the 1k resistor in place of of the sensor.(it wont hurt your system.)
If your compressor kicks on and you start feeling cold air then the problem is your evap temp switch is bad.
If the compressor still doesn't kick on then you are probably low on freon and might have a leak.
Hope this helps
Rusty
MBWorld Fanatic!
Joined: Apr 2005
Posts: 3,784
Likes: 84
From: SCV SoCal
2002 CLK430
E Harmon,
Try this trick, I call it my 99 cent fix. I did this to T/Shoot the problem I had in my CLK & E320...
Get a 1k ohm resistor (form radio shack or a local electronics store). find and pull out your evap temp switch. (underneath the drivers side).
Disconnect the evap sensor and place the 1k resistor in place of of the sensor.(it wont hurt your system.)
If your compressor kicks on and you start feeling cold air then the problem is your evap temp switch is bad.
If the compressor still doesn't kick on then you are probably low on freon and might have a leak.
Hope this helps
Rusty
Try this trick, I call it my 99 cent fix. I did this to T/Shoot the problem I had in my CLK & E320...
Get a 1k ohm resistor (form radio shack or a local electronics store). find and pull out your evap temp switch. (underneath the drivers side).
Disconnect the evap sensor and place the 1k resistor in place of of the sensor.(it wont hurt your system.)
If your compressor kicks on and you start feeling cold air then the problem is your evap temp switch is bad.
If the compressor still doesn't kick on then you are probably low on freon and might have a leak.
Hope this helps
Rusty
If this is the problem, e Harmon is $40 in parts from ice cold AC.
MBWorld Fanatic!
Joined: Feb 2007
Posts: 1,348
Likes: 2
From: Northern VA / DC
CLK 320 (2001) and 2015 GTR
My A/C isn't cold at all too. unfortunately it just happened recently. but what does those numbers mean? kinda lost me there
do you know where the A/C piping is located? I don't even know where to start. Last summer i paid over $500 at the dealer for... inspection / recharging the a/c / and connecting the loose tubing. i'm definitely not paying that kinda' money this time around.
do you know where the A/C piping is located? I don't even know where to start. Last summer i paid over $500 at the dealer for... inspection / recharging the a/c / and connecting the loose tubing. i'm definitely not paying that kinda' money this time around.
NP, i will take a pic with my cell and post it 2nite.
i had two leaks , first one costed me $475 and second one $240...
i will take pics for ya
MBWorld Fanatic!
Joined: Feb 2008
Posts: 1,261
Likes: 21
From: SoCaL (LA / OC)
E55 AMG (SOLD), EvoSport CLK (SOLD), 2013 GsxR 750 (SOLD)
H&R kit since day one. just been playing around with different settings.
thanks in advance bro. i appreciate it. It's starting to get real hot too, it sucks cause everytime i drive, i HAVE TO roll with the windows down whether i like it or not. sucks
Thread Starter
Member
Joined: Jun 2005
Posts: 86
Likes: 0
From: Miami, FL
2000 CLK 430 Coupe
E Harmon,
Try this trick, I call it my 99 cent fix. I did this to T/Shoot the problem I had in my CLK & E320...
Get a 1k ohm resistor (form radio shack or a local electronics store). find and pull out your evap temp switch. (underneath the drivers side).
Disconnect the evap sensor and place the 1k resistor in place of of the sensor.(it wont hurt your system.)
If your compressor kicks on and you start feeling cold air then the problem is your evap temp switch is bad.
If the compressor still doesn't kick on then you are probably low on freon and might have a leak.
Hope this helps
Rusty
Try this trick, I call it my 99 cent fix. I did this to T/Shoot the problem I had in my CLK & E320...
Get a 1k ohm resistor (form radio shack or a local electronics store). find and pull out your evap temp switch. (underneath the drivers side).
Disconnect the evap sensor and place the 1k resistor in place of of the sensor.(it wont hurt your system.)
If your compressor kicks on and you start feeling cold air then the problem is your evap temp switch is bad.
If the compressor still doesn't kick on then you are probably low on freon and might have a leak.
Hope this helps
Rusty
I mentioned the switch to my mechanic. I brought it back to him since he replaced the compressor and drier 6 months ago, and I wanted to rule out a possible residual issue with that installation.
He did mention that it might be the evaporator, based on the observation I made that up until a few weeks ago, I would smell something right after starting the car that I figured might be washer fluid, since he changed those out right before the smell started.
I am definitely hoping for just about anything besides the evaporator. I'll keep the resistor in mind if it's not something else simple.
Thanks again all.
Regards,
e harmon
MBWorld Fanatic!
Joined: Feb 2007
Posts: 1,348
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From: Northern VA / DC
CLK 320 (2001) and 2015 GTR
OK, TOOK EM WITH MY CELL..
FIRST 2 PICS(MEDIA 1 AND 2) WAS A REGULAR LEAK DUE TO THE PRESSURE AND LASTED FOR 3 WEEKS AND AC WAS BLOWING HOT AIR, THEY CHECKED IT ALL AND KEPT ON TELLIN ME MY CAR IS FINE, TILL THEY RECHECKED MY LAST PIPING AND IT WAS THE MAJOR ONE THAT WAS LEAKING.. IT WAS LEAKING WHERE THE METAL IS CAPPED ON THE HOSE.(MEDIA 3 AND 4 RUN ON THE TOP OF THE FENDER (TO THE SIDE) )
NOW ITS LIKE A FREEZER IN MY CAR AND I FEEL YA, I HATE IT WHEN SOMETHING DOES NOT WORK
HOPE I HAVE HELPED YA OUT.
ASK EM TO PUT THAT YELLOW DYE AND WEAR THOSE YELLOW SHADES TO SEE THE LEAK...
Member
Joined: Feb 2008
Posts: 75
Likes: 3
From: Chandler, AZ
2001 C320, 1997 E320, 1993 300e & 2005 F150 Supercrew
Good guess. The switch itself could be bad. The switch reads 88 degrees, but if it's got an internal short, the compressor will never engage and he'll never get see Freon pressure. Although . . . . . . I've never checked pressure at the HVAC display with the AC off. Someone want to post the #7 reading on a car with the AC off?
If this is the problem, e Harmon is $40 in parts from ice cold AC.
The numbers are explained here. Those numbers make AC diagnostics a lot easier.
If this is the problem, e Harmon is $40 in parts from ice cold AC.
The numbers are explained here. Those numbers make AC diagnostics a lot easier.
I forgot to add to start the car then check to see if the compressor kicks on. If it does it's the sensor if not then maybe he's low on Freon. My bad.
MBWorld Fanatic!
Joined: Feb 2008
Posts: 1,261
Likes: 21
From: SoCaL (LA / OC)
E55 AMG (SOLD), EvoSport CLK (SOLD), 2013 GsxR 750 (SOLD)
NICE I SHOULD BE AS LOW AS URS ON MY 19 NOW.. PICS ARE COMING SAT.
OK, TOOK EM WITH MY CELL..
FIRST 2 PICS(MEDIA 1 AND 2) WAS A REGULAR LEAK DUE TO THE PRESSURE AND LASTED FOR 3 WEEKS AND AC WAS BLOWING HOT AIR, THEY CHECKED IT ALL AND KEPT ON TELLIN ME MY CAR IS FINE, TILL THEY RECHECKED MY LAST PIPING AND IT WAS THE MAJOR ONE THAT WAS LEAKING.. IT WAS LEAKING WHERE THE METAL IS CAPPED ON THE HOSE.(MEDIA 3 AND 4 RUN ON THE TOP OF THE FENDER (TO THE SIDE) )
NOW ITS LIKE A FREEZER IN MY CAR AND I FEEL YA, I HATE IT WHEN SOMETHING DOES NOT WORK
HOPE I HAVE HELPED YA OUT.
ASK EM TO PUT THAT YELLOW DYE AND WEAR THOSE YELLOW SHADES TO SEE THE LEAK...
OK, TOOK EM WITH MY CELL..
FIRST 2 PICS(MEDIA 1 AND 2) WAS A REGULAR LEAK DUE TO THE PRESSURE AND LASTED FOR 3 WEEKS AND AC WAS BLOWING HOT AIR, THEY CHECKED IT ALL AND KEPT ON TELLIN ME MY CAR IS FINE, TILL THEY RECHECKED MY LAST PIPING AND IT WAS THE MAJOR ONE THAT WAS LEAKING.. IT WAS LEAKING WHERE THE METAL IS CAPPED ON THE HOSE.(MEDIA 3 AND 4 RUN ON THE TOP OF THE FENDER (TO THE SIDE) )
NOW ITS LIKE A FREEZER IN MY CAR AND I FEEL YA, I HATE IT WHEN SOMETHING DOES NOT WORK
HOPE I HAVE HELPED YA OUT.
ASK EM TO PUT THAT YELLOW DYE AND WEAR THOSE YELLOW SHADES TO SEE THE LEAK...
thanks mike, i'm definitely gonna check it out tomorrow morning when the sun's out. hopefully based on your pictures i'll be able to pinpoint the exact same locations that you showed, cause i have a feeling i may fail to find one of them.
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Joined: Apr 2005
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From: SCV SoCal
2002 CLK430
No problem Rusty. We're all just trying to help him out. And speaking of such, I put mine in diagnostic mode with the car turned off. After it had been sitting for several hours, #7 still showed pressure. Unfortunately, I think the system may have a leak.
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Posts: 1,261
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From: SoCaL (LA / OC)
E55 AMG (SOLD), EvoSport CLK (SOLD), 2013 GsxR 750 (SOLD)
MBWorld Fanatic!
Joined: Feb 2007
Posts: 1,348
Likes: 2
From: Northern VA / DC
CLK 320 (2001) and 2015 GTR
good luck
if all is working fine from compressor to motor ect... and FREON is low, U HAVE TO HAVE A leak somewhere in one of those hoses..
MBWorld Fanatic!
Joined: Feb 2007
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From: Northern VA / DC
CLK 320 (2001) and 2015 GTR
AND ALSO LOOK UNDER THE METAL CAPS ON THE HOSE FROM ALL DIRECTION AND AROUND IT (THAT IS WHERE I HAD THE LEAK)..
SORRY I LEFT MY CAPS ON.. IM NOT SCREAMING AT U LOL
Last edited by big_mike1979; Jun 9, 2010 at 06:13 PM.
MBWorld Fanatic!
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Posts: 1,261
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From: SoCaL (LA / OC)
E55 AMG (SOLD), EvoSport CLK (SOLD), 2013 GsxR 750 (SOLD)
YES CHIEF.. MEANS u had a leak B4 IT MUST DRIED ON THE HOSE AND ONLY WAY TO FIND THE NEW ONE OVER THE STAIN, IS TO INJECT THE DYE AND PUT THE SHADES ON AND FOLLOW THE HOSES.. CHECK EM ALL AND U CAN SEE THE LEAK BECOME WET YELLOW.. U WILL KNOW WHAT I MEAN ONCE U FIND IT.
AND ALSO LOOK UNDER THE METAL CAPS ON THE HOSE FROM ALL DIRECTION AND AROUND IT (THAT IS WHERE I HAD THE LEAK)..
SORRY I LEFT MY CAPS ON.. IM NOT SCREAMING AT U LOL
AND ALSO LOOK UNDER THE METAL CAPS ON THE HOSE FROM ALL DIRECTION AND AROUND IT (THAT IS WHERE I HAD THE LEAK)..
SORRY I LEFT MY CAPS ON.. IM NOT SCREAMING AT U LOL
haha. no worries bro. i'll definitely see what i can do today, i might roll to my boy's shop and hopefully he could hook me up. if anything, i'll keep you posted.
Thread Starter
Member
Joined: Jun 2005
Posts: 86
Likes: 0
From: Miami, FL
2000 CLK 430 Coupe
It turns out that my car had a faulty O ring on a line going into the compressor. Replaced it and recharged the system, working fine now. I've decided a working AC is the best possible upgrade in 92 degree weather. 
Thanks again to all. I'll keep these helpful tips filed away in case of problems down the line.
Regards,
e harmon
Thanks again to all. I'll keep these helpful tips filed away in case of problems down the line.
Regards,
e harmon
Last edited by e harmon; Jun 9, 2010 at 08:58 PM. Reason: typo
MBWorld Fanatic!
Joined: Feb 2007
Posts: 1,348
Likes: 2
From: Northern VA / DC
CLK 320 (2001) and 2015 GTR
Member
Joined: Feb 2008
Posts: 75
Likes: 3
From: Chandler, AZ
2001 C320, 1997 E320, 1993 300e & 2005 F150 Supercrew
It turns out that my car had a faulty O ring on a line going into the compressor. Replaced it and recharged the system, working fine now. I've decided a working AC is the best possible upgrade in 92 degree weather.
Thanks again to all. I'll keep these helpful tips filed away in case of problems down the line.
Regards,
e harmon
Thanks again to all. I'll keep these helpful tips filed away in case of problems down the line.
Regards,
e harmon
