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Anyone experiencing issues with GLS A/C not cooling?
I do have black exterior, black interior, black headliner and sun roof (wish screen was thicker/blocked more sun), so it is sucks up heat.
I have the same exact vehicle but not have experience loss of cooling. Does it make a difference if you put it on max AC? Someone also responded that it was a maintenance item but I did not find it in the manual. Keep us updated.
I have the same exact vehicle but not have experience loss of cooling. Does it make a difference if you put it on max AC? Someone also responded that it was a maintenance item but I did not find it in the manual. Keep us updated.
AC recharge is not a binary phenomenon. Some cars need it at 5 years, some at 10, some maybe not at all.
Make sure the airflow is set on ‘Focus’ and not ‘diffuse’. Took me a few years
to discover, but the diffuse setting is a little bit less cold air (temperature wise).
Make sure the airflow is set on ‘Focus’ and not ‘diffuse’. Took me a few years.
to discover, but the diffuse setting is a little bit less cold air (temperature wise).
Good point, also make sure you set the airflow to the dashboard vents. Realized on one of the first hot days of the year, that the airflow was being sent to the windshield
Here in Phoenix the a/c in our 550 struggles for the first 10-15 minutes of driving. It's been to Mercedes a year ago, they replaced refrigerant lines that go to the rear evaporator and recharged the whole system. After that it was definitely better, but even still, the a/c for the driver and passenger gets cool about 30 seconds into driving, but the rear seat passenger vents don't blow any cold air for at least 5-10 MINUTES into the drive. It's pretty frustrating (yes, "Focus" is selected, everything set to auto, temp set to 68 (not zone'ed)). We have an 18 month old and one of the big reasons we bought the car was for the rear a/c vents, but they're useless for many agonizing minutes. They literally blow no air at all for a few minutes, then they start blowing semi-cool air, then it finally gets cold after 10 minutes or so. It's like the system is prioritizing the driver/passenger area first. I had the system checked a few weeks ago and it's supposedly perfect. The a/c in my 2017 F150 is ice cold twice as fast and the rear seats get COLD air coming out of the vents within 20 seconds. I also love the actual air conditioned seats in the truck compared to the ventilated seats in the GLS.
Between this issue and how fast the car destroys rear tires, we're entertaining offers to sell it.
Here in Phoenix the a/c in our 550 struggles for the first 10-15 minutes of driving. It's been to Mercedes a year ago, they replaced refrigerant lines that go to the rear evaporator and recharged the whole system. After that it was definitely better, but even still, the a/c for the driver and passenger gets cool about 30 seconds into driving, but the rear seat passenger vents don't blow any cold air for at least 5-10 MINUTES into the drive. It's pretty frustrating (yes, "Focus" is selected, everything set to auto, temp set to 68 (not zone'ed)). We have an 18 month old and one of the big reasons we bought the car was for the rear a/c vents, but they're useless for many agonizing minutes. They literally blow no air at all for a few minutes, then they start blowing semi-cool air, then it finally gets cold after 10 minutes or so. It's like the system is prioritizing the driver/passenger area first. I had the system checked a few weeks ago and it's supposedly perfect. The a/c in my 2017 F150 is ice cold twice as fast and the rear seats get COLD air coming out of the vents within 20 seconds. I also love the actual air conditioned seats in the truck compared to the ventilated seats in the GLS.
Between this issue and how fast the car destroys rear tires, we're entertaining offers to sell it.
For what it is worth, I had a 2001 Dodge Durango that I was sure the a/c was not working correctly. It sat in a parking lot in Houston all day in the sun. When I would get in to go home, the a/c struggled to cool it down. I read somewhere to do the following and it really helped. When you start the car, roll down all four windows. This helps to immediately blow out the 120+ deg air and replace with with 95. Do NOT use recirculate for the same reason. The dash and the roof temp are still way above the outside air temp. So pull in the 95 deg air for about 5 mins. Then roll up all the windows and still leave the recirculate off. It worked so well that to this day I do not use recirculate in my '14 GL450 or my wife's all black '14 ML350.
For what it is worth, I had a 2001 Dodge Durango that I was sure the a/c was not working correctly. It sat in a parking lot in Houston all day in the sun. When I would get in to go home, the a/c struggled to cool it down. I read somewhere to do the following and it really helped. When you start the car, roll down all four windows. This helps to immediately blow out the 120+ deg air and replace with with 95. Do NOT use recirculate for the same reason. The dash and the roof temp are still way above the outside air temp. So pull in the 95 deg air for about 5 mins. Then roll up all the windows and still leave the recirculate off. It worked so well that to this day I do not use recirculate in my '14 GL450 or my wife's all black '14 ML350.
I appreciate the reply, but driving with the windows down for 5+ minutes is just not feasible when it's 110+ out.
My wife just got home from a 25 minute drive from work. She was visibly a little sweaty and the crappy a/c in the car was the first thing she told me about when she walked in the door. I know the a/c is supposedly "within spec" but it's probably just time to look at other SUV's that can handle Phoenix heat. My F150 did awesome today in stop and go traffic as I ran a few errands, a/c was ice cold. I'll probably switch vehicles with her until we find something to replace the otherwise awesome GLS.
Sounds like it isn't. Surely you have some AC specialists in the area. I'd get a second opinion.
Drive with the windows partially down just long enough to replace the 150 degree air with 110 degree air. With the windows shut, recirculate prevents you from having to cool 110 degree air over and over. (Just poke "auto").
Even brand new cars right off the factory floor sometimes come with low refrigerant levels.
Have it checked.
I mentioned in the post that I just had it checked, it’s perfect according to Mercedes.
Does everyones cooling fans who live in hot climates sound like the fans are screaming? Like running at max power when the AC is on? Our 550’s sound like they’re barely running at all. Every time we come to a stop the AC seems to stop working, then gets cool again after we get moving. Beginning to think this is a cooling fan issue. Bad relay? Bad sensor?
OK - Now I think that I have a different problem vs AC charge. My wife was in passenger seat and AC was blowing cold while I was still getting hot air 10 minutes into a drive. The system was not set for separate zones. I changed to diffuse and the air got cooler, not as cold as the vent from the passenger side, but cooler. Some kind of vent actuator problem?
This has come up on the site, not sure when or for which vehicle. Are you sure of the climate control settings? AUTO or manual? If manual, what were the settings for temp (both sides), fan, AC and mode/vent?
This has come up on the site, not sure when or for which vehicle. Are you sure of the climate control settings? AUTO or manual? If manual, what were the settings for temp (both sides), fan, AC and mode/vent?
Auto, focused, 68 degrees, not zoned, just one temp for all 3 zones. Max a/c makes no difference, but I *have* noticed that in that mode, it obviously prefers the front zones because I noticed that after starting the car and putting in that mode, it sends ALL of the cool air to the front vents ONLY, the rear seat vents aren't putting out any air AT ALL, the blower motor back there is shut totally off. About 10 minutes into the drive, I noticed it's as if the car has determined one of two things - either the front two zones are at an acceptable temperature, or that there is now enough cooling capacity to begin sending freon to the rear evaporator because all of a sudden you hear the rear vents come on full blast (but they're still putting out warm-ish air for at least another 5-7 minutes or so. Nothing like being blasted with 100 degree air when it's 110 out). We were sitting at a light when the rear vents suddenly turned on on their own and we both looked at each other wondering what that was all about.
We've been at the hospital the last few days because my wife gave birth to our 2nd child, a very healthy baby boy! So excited about our other son having a little brother to play with now. But it's been real hot here in Phoenix (110+ all afternoon) and I knew the car had been baking out there in the sun (it's normally parked in our garage). I actually made it a point to try and time it where I could bring down all of our stuff, get it in the car, and drive the car around for a while and then get back to the hospital to pick them up because I knew it wasn't going to be comfortable in there at all for basically our entire 30 minute drive home. So I get in the car and immediately head for the freeway which is about 5 minutes away, a/c set to 68 degrees, auto, recirc (I had the windows cracked all day so it was no hotter inside than it was outside). The a/c is blowing luke-warm all the way up until I'm a few minutes down the freeway doing 70 mph and I *start* to feel the a/c cool things down. But really, it doesn't get cold until about 10 or 12 minutes into the drive, at minimum. I'm trying to stay close to the hospital so I get off the freeway and head for a gas station to fill up, and at every light, the a/c starts blowing WARM air. After I get gas I get back on the freeway heading back and the a/c is finally blowing cold air, at least in the front (the rear vents are blowing cool-ish) but this is now about 25 minutes into my drive. I arrive back at the hospital as they are wheeling my wife and son out of the maternity entrance. Mission accomplished I guess? But that's beyond ridiculous.
One thing I noticed since I've been paying more attention to the a/c condensor fan is if I hear it or not. Today, when I started my drive to cool the car down, it was running, but seemingly at the low speed setting. After all the driving I did, I started to notice it was definitely running at the high or higher speed, and if I stopped at a light, it no longer was blowing warm air out of the vents. I started to think that it might have helped if they were running like that earlier in the drive. Our old 2015 GLK 350 got sold to my wife's parents, and the cooling fans on that are ROARING when it's hot out, and it has awesome a/c almost immediately when you start it up.
I'm trying to find a local shop that will take a look, but 2 so far have said they won't even attempt it because it's a Mercedes, and they are 5 star rated with lots of great reviews. I guess I'm going to keep looking and trying to focus now on the a/c condensor fan being the culprit.
Auto, focused, 68 degrees, not zoned, just one temp for all 3 zones. Max a/c makes no difference, but I *have* noticed that in that mode, it obviously prefers the front zones because I noticed that after starting the car and putting in that mode, it sends ALL of the cool air to the front vents ONLY, the rear seat vents aren't putting out any air AT ALL, the blower motor back there is shut totally off. About 10 minutes into the drive, I noticed it's as if the car has determined one of two things - either the front two zones are at an acceptable temperature, or that there is now enough cooling capacity to begin sending freon to the rear evaporator because all of a sudden you hear the rear vents come on full blast (but they're still putting out warm-ish air for at least another 5-7 minutes or so. Nothing like being blasted with 100 degree air when it's 110 out). We were sitting at a light when the rear vents suddenly turned on on their own and we both looked at each other wondering what that was all about.
We've been at the hospital the last few days because my wife gave birth to our 2nd child, a very healthy baby boy! So excited about our other son having a little brother to play with now. But it's been real hot here in Phoenix (110+ all afternoon) and I knew the car had been baking out there in the sun (it's normally parked in our garage). I actually made it a point to try and time it where I could bring down all of our stuff, get it in the car, and drive the car around for a while and then get back to the hospital to pick them up because I knew it wasn't going to be comfortable in there at all for basically our entire 30 minute drive home. So I get in the car and immediately head for the freeway which is about 5 minutes away, a/c set to 68 degrees, auto, recirc (I had the windows cracked all day so it was no hotter inside than it was outside). The a/c is blowing luke-warm all the way up until I'm a few minutes down the freeway doing 70 mph and I *start* to feel the a/c cool things down. But really, it doesn't get cold until about 10 or 12 minutes into the drive, at minimum. I'm trying to stay close to the hospital so I get off the freeway and head for a gas station to fill up, and at every light, the a/c starts blowing WARM air. After I get gas I get back on the freeway heading back and the a/c is finally blowing cold air, at least in the front (the rear vents are blowing cool-ish) but this is now about 25 minutes into my drive. I arrive back at the hospital as they are wheeling my wife and son out of the maternity entrance. Mission accomplished I guess? But that's beyond ridiculous.
One thing I noticed since I've been paying more attention to the a/c condensor fan is if I hear it or not. Today, when I started my drive to cool the car down, it was running, but seemingly at the low speed setting. After all the driving I did, I started to notice it was definitely running at the high or higher speed, and if I stopped at a light, it no longer was blowing warm air out of the vents. I started to think that it might have helped if they were running like that earlier in the drive. Our old 2015 GLK 350 got sold to my wife's parents, and the cooling fans on that are ROARING when it's hot out, and it has awesome a/c almost immediately when you start it up.
I'm trying to find a local shop that will take a look, but 2 so far have said they won't even attempt it because it's a Mercedes, and they are 5 star rated with lots of great reviews. I guess I'm going to keep looking and trying to focus now on the a/c condensor fan being the culprit.
Congratulations and blessings on the birth of your son!
This has come up on the site, not sure when or for which vehicle. Are you sure of the climate control settings? AUTO or manual? If manual, what were the settings for temp (both sides), fan, AC and mode/vent?
I always start with the following settings:
AUTO ON
ZONE OFF(one temp for all and REAR ON)
TEMP 74 degrees
FOCUS
RECIRCULATE OFF
Auto, focused, 68 degrees, not zoned, just one temp for all 3 zones. Max a/c makes no difference, but I *have* noticed that in that mode, it obviously prefers the front zones because I noticed that after starting the car and putting in that mode, it sends ALL of the cool air to the front vents ONLY, the rear seat vents aren't putting out any air AT ALL, the blower motor back there is shut totally off. About 10 minutes into the drive, I noticed it's as if the car has determined one of two things - either the front two zones are at an acceptable temperature, or that there is now enough cooling capacity to begin sending freon to the rear evaporator because all of a sudden you hear the rear vents come on full blast (but they're still putting out warm-ish air for at least another 5-7 minutes or so. Nothing like being blasted with 100 degree air when it's 110 out). We were sitting at a light when the rear vents suddenly turned on on their own and we both looked at each other wondering what that was all about.
We've been at the hospital the last few days because my wife gave birth to our 2nd child, a very healthy baby boy! So excited about our other son having a little brother to play with now. But it's been real hot here in Phoenix (110+ all afternoon) and I knew the car had been baking out there in the sun (it's normally parked in our garage). I actually made it a point to try and time it where I could bring down all of our stuff, get it in the car, and drive the car around for a while and then get back to the hospital to pick them up because I knew it wasn't going to be comfortable in there at all for basically our entire 30 minute drive home. So I get in the car and immediately head for the freeway which is about 5 minutes away, a/c set to 68 degrees, auto, recirc (I had the windows cracked all day so it was no hotter inside than it was outside). The a/c is blowing luke-warm all the way up until I'm a few minutes down the freeway doing 70 mph and I *start* to feel the a/c cool things down. But really, it doesn't get cold until about 10 or 12 minutes into the drive, at minimum. I'm trying to stay close to the hospital so I get off the freeway and head for a gas station to fill up, and at every light, the a/c starts blowing WARM air. After I get gas I get back on the freeway heading back and the a/c is finally blowing cold air, at least in the front (the rear vents are blowing cool-ish) but this is now about 25 minutes into my drive. I arrive back at the hospital as they are wheeling my wife and son out of the maternity entrance. Mission accomplished I guess? But that's beyond ridiculous.
One thing I noticed since I've been paying more attention to the a/c condensor fan is if I hear it or not. Today, when I started my drive to cool the car down, it was running, but seemingly at the low speed setting. After all the driving I did, I started to notice it was definitely running at the high or higher speed, and if I stopped at a light, it no longer was blowing warm air out of the vents. I started to think that it might have helped if they were running like that earlier in the drive. Our old 2015 GLK 350 got sold to my wife's parents, and the cooling fans on that are ROARING when it's hot out, and it has awesome a/c almost immediately when you start it up.
I'm trying to find a local shop that will take a look, but 2 so far have said they won't even attempt it because it's a Mercedes, and they are 5 star rated with lots of great reviews. I guess I'm going to keep looking and trying to focus now on the a/c condensor fan being the culprit.
Congrats on the birth of your son!!!
This is not meant to be a solution for your a/c troubles, just something I found helpful. When our GLS has been parked in the sun and is boiling hot inside, I found if I open the side panel windows near the the third seat, the car cools much faster. The interior heat gets pushed out through those rear most vent windows. I close them after a few minutes of driving.
Another thought, have tried using the remote start app to let the a/c run for awhile before you get in to drive it?
Not suggesting your a/c doesn't have other issues. Good luck!
More info for all to ponder; when I experienced warm/not cold air, usually had service look for problem. First time they found an o ring needing to be replaced and recharged. Ran cold immediately and 2 seasons later cold went away. 2nd time they stated it just needed a recharge, so cold immediately returned. 2 seasons later, warm air returned again. Before I could get it in for service, the AC unit locked up and broke the belt, so complete new AC unit that time. Ran great for a while and then air was not getting as cold again. It wasn’t warm, but wasn’t ice cold either. This time I decided to check myself with a recharge unit from auto store (this unit had digital gauge). It registered at the low end of the spec, so I slowly filled it toward the higher end. Very cold air returned. I’ll keep chasing (I suspect a slow leak somewhere) but glad to know $50 and 15 minutes is a quick fix rather than scheduling service in 100 degree Florida weather. If that is an every two year item, I’m not that worried.
As far as rear vents taking a while to cool, I discussed with tech and he gave me what sounded like a reasonable explanation. The ducts to the rear vents run along the roof line. When the car sits, especially in the sun, that ductwork gets super heated and takes a while to cool down (via the cold air) before the cold reaches the vents themselves. Sounds reasonable, although I would not expect this of MB at this price point.
This is not meant to be a solution for your a/c troubles, just something I found helpful. When our GLS has been parked in the sun and is boiling hot inside, I found if I open the side panel windows near the the third seat, the car cools much faster. The interior heat gets pushed out through those rear most vent windows. I close them after a few minutes of driving.
Another thought, have tried using the remote start app to let the a/c run for awhile before you get in to drive it?
Not suggesting your a/c doesn't have other issues. Good luck!
There are times I wish we still had the remote start, but couldn't really justify the yearly cost. The issue seems to mainly be when we first start up the car and if it's above around 105 out. This morning I had to go somewhere and it was "only" about 90 out and the a/c was nice and cold within 20 seconds. There definitely seems to be some correlation between ambient temp and how fast the a/c decides to start cooling down, and I also still suspect the condensor fan.
Originally Posted by Jpkcpa
More info for all to ponder; when I experienced warm/not cold air, usually had service look for problem. First time they found an o ring needing to be replaced and recharged. Ran cold immediately and 2 seasons later cold went away. 2nd time they stated it just needed a recharge, so cold immediately returned. 2 seasons later, warm air returned again. Before I could get it in for service, the AC unit locked up and broke the belt, so complete new AC unit that time. Ran great for a while and then air was not getting as cold again. It wasn’t warm, but wasn’t ice cold either. This time I decided to check myself with a recharge unit from auto store (this unit had digital gauge). It registered at the low end of the spec, so I slowly filled it toward the higher end. Very cold air returned. I’ll keep chasing (I suspect a slow leak somewhere) but glad to know $50 and 15 minutes is a quick fix rather than scheduling service in 100 degree Florida weather. If that is an every two year item, I’m not that worried.
As far as rear vents taking a while to cool, I discussed with tech and he gave me what sounded like a reasonable explanation. The ducts to the rear vents run along the roof line. When the car sits, especially in the sun, that ductwork gets super heated and takes a while to cool down (via the cold air) before the cold reaches the vents themselves. Sounds reasonable, although I would not expect this of MB at this price point.
Thanks.. yea I had it checked at Mercedes about a month ago and they said it was fine. I bought one of those a/c recharge canisters with the gauges on it and it also said the freon level was right near the max. When the a/c runs great like it did this morning, it's SUPER cold, almost too cold to where I want to turn the temperature up, but there is some kind of issue when it gets hotter out that the system really really struggles. And the weird thing is the difference in ambient temp is only about 15 degrees between it running really well and basically not running at all. As for the rear seats, I know that there is a 2nd (separate) evaporator core back there with dedicated refrigerant lines running to it from the main compressor, but those lines are only activated in certain conditions as I'm discovering.
I took it to an independent shop this morning and they said it was down about a half of a pound of freon. The system holds 2 lbs 12 oz so a half of a pound is significant. They then got out their UV flashlight and we found the source of the leak - guess where? The connection that sends freon to the rear evaporator, right above the transmission. This set of lines going back there are the ones Mercedes replaced last year. The shop vacuumed out and then recharged the system, and now the a/c is VERY cold, so this was definitely the issue. Going to have to fight it out now with Mercedes considering it's going to be very expensive to get at these lines, possibly requiring the removal of the transmission.. again. I think it's really shady of Mercedes to say the system was ok. I'm assuming they just didn't want to deal with fixing this again. I'd avoid Mercedes of Gilbert Arizona if you can.
It's 5+ years old. Time for an AC evac and recharge. This is a maintenance item.
I took vehicle in and they said it had about half the refrigerant it should have. Now it gets really cold quickly. We’ll see how it does next time it has to sit in the hot Sun. Now on to the next maintenance item…
06-25-2022, 12:19 PM
