cunim

Driving my 450 through the heat waves I find the AC performance pretty marginal. I have to keep the set temp at about 16'C to get much cool air, and the fan is really loud at that setting. I remember in the winter, the fan was also loud when heat was called for so I suppose these cars just have loud fans. However, I don't remember a problem getting enough heat. None of our other cars have such poor AC performance and that sample includes a BMW that is 13 years old and a 10 year old Audi.

I have seen the thread about the AC failing and blowing hot air, but my own issue is not a failure. Cooling still functions. It is just that the system is barely able to cope. Is this the way the all are or is my car in the process of failing?

paulmj1

It was 110 here in Arizona yesterday. The A/C in our 350 works fine, cools the car rapidly and it stays there with minimal fan speed. I would have yours checked.

ygmn

What was engine RPMS?
Speed?

AMbient temp?
Sun shine?
Humidty?

All these things affect AC performance.
If on interstate for 10-15 mins and you are not cool... then I would have it checked...

user 7208224

I have no issues with the a/c in my 350. I have it set at 70 deg F. I usually have my side sunscreens up and my pano roof screen closed to help keep the sun load down, if that is any help. Good luck.

JustBlessed

I just posted this exact question on FB. I have a 2020 350 not even 2 months old. There has got to be something wrong with the system. It cools
fine but it blows louder than a loud radio. I’ve asked about the ‘Auto and ‘Blower speed but got different responses. I always keep in Auto but sometimes I could change the blower speed and sometimes I can’t. I know for sure that when the temp is set to LOW even putting the blower speed all the way down it’s Still blowing at full force and just as loud.

Ron.s

I think it’s normal for the AC to start at the highest fan speed on Auto. After a few minutes you can reduce fan speed. There may be a logical reason to have it work that way.

JustBlessed

yea I’m talking 20-30 minutes after driving. And on multiple different occasions.

Ron.s

Those are the tough ones to get fixed since the Dealer is usually required to be able to replicate the issue. My suggestion would be to make a recording showing you pushing the fan button as well as describing the time line since you started the car. If it lasts longer make another recording and describe the time lapse again.
When my MBUX Control module started going bad I had some different but unusual issues that might repeat or might not repeat. I made some recordings and between my Dealer and Tech support they figured it out. I was convinced that it was software code conflicts and insisted that’s what it almost had to be. A year later and everything is still working.

TexAg91

Mine cools down quickly, and then slows the fans speed. You might as well take it in and have the dealer check it out...if the air isn't cold there could be an issue with it.

cunim

Thanks for the replies. Some of you have no problem so a well adjusted GLE can manage a moderately hot and humid day. In contrast, mine can only keep the interior on the warm side of comfortable, even though the heat and humidity here is not that bad (Canada). I think because the air isn't very cold, the system tries to move a lot of it - causing the loud fan. If I turn down the fan, the car gets too warm.

It does work, but something is failing. I will take it in when I can get an appointment scheduled.

Lucky 777

The only negative observation I've made is the auto start if you're in town or suburban traffic. Turn that off so the engine continues to run at stops.

tiri

I too have issues with my Thermotronic HVAC.
There is no air at all coming out of the vent to the left of the steering wheel regardless of fan speed.
When temps and fan speed are synced with the driver's position, all four zones work, but as soon as I change any setting for either of the two zones in the rear, the fan speed drops to the lowest setting from the rear center console, regardless of what fan speed intensity is displayed.
At least the B-Pillar vents continue to blast air.

user 7208224

I know that the a/c in the 350 runs off of a belt, but is the a/c in the 450 electric or off of a belt? Curious because of the 48 volt system.

Lucky 777

Make sure your left and right zones are sync'd as I've seen a large difference between the two cause erratic operation. They do operate independently but always felt it was more of a placebo effect for the co pilot.

bad habit

What I realized recently is that is doesn't cool super efficiently, if have enabled for it to blow on feet, center, and windshield at the same time. Seems best setup is center and feet.
Also, synced, as Lucky mentioned. What I really find annoying as that the windshield has no solar insulation at all, I am looking at some ceramic window films and might do that.

P.S. paging @places so he can say that the GLE is "full of problems"

jcapotos

The 450 with the 48v system runs all accessories by electric. There are no belts on this engine. I have no issues with AC

Ralph112

I too was originally thinking that my AC was not as efficient as it should be, so i did an experiment.
Set the ac to the lowest temp (60F)
Outside temp was 98F
Set it to air circulate mode.
Fan speed at 3
Drove for 15 minutes so that the system had enough time to power up
and then parked the car and did a thermogun reading at the front vents. The readings were all over the place depending on where in the vent was i pointing the laser beam. ( Empty spaces vs horizontal slats vs chrome tip etc.)
But all 6 vents in the front showed a consistent ~35F as the MIN temparature. Hope this helps.

TexAg91

Check the simple stuff first -- make sure you have all the "oreo pucks" under the all the A/C vents in the full open position. I noticed that when they are partially closed (or fully closed), it restricts the airflow and is loud.

fabbrisd1

Yes - highest fan levels are "loud" - the system however is quite efficient - and frankly I don't recommend "Low" temp setting - as running at Low for any period of time tends to "frost up" the evaporator which leads to a self-fulfilling expectation of decreased system efficiency.... I usually keep mine at 72 .. the system on hot days will take the fans to max - which I tolerate a min or two then manually set the fan down two levels - and return to Auto when I feel cool enough.

Yes - Crystalline DuPont film can be used to add UV/IR reduction to the front windshield - some swear by it - others use a fold-out on the windshield when parked in the sun.

at t 2d

I have the ceramic film on the windshields of all our cars and it really makes a big difference in keeping them cool and does not impede forward vision at all.

ygmn

Say what?

They are designed not to freeze over that only happens when low on refridgerant like a home system..
OR can happen when air flow is not enough...
but if it happens you have a problem. it is not normal
SO crank it low if hot.

But per manual one should set temp to what you want the inside temp to be, like your HOUSE...
The computers and stuff in the car will controll the compressor run time, air speed and blend doors to get cabin to that temp and hold it.

bad habit

Which one are you using?

at t 2d

I checked the last few cars I have tinted and the windshields were SunTek Ceramic. It was recommended by the shop I have been using for about 10 years.

bigpern23

Got mine in December, so there wasn't any need for A/C during the first six months I had it. First time I used the A/C, I set the temp to 65 and couldn't understand why it wasn't cooling me off. Finally, 15 minutes later at a stop light, I realized I hadn't actually pressed the A/C toggle switch on the dash. I had just assumed that setting the temperature would get me to the desired comfort level. Pretty dumb, but I doubt I'm the first or last person to do so.

drmfodo

I too was having problems with vehicle cooling and then discovered the Auto Fan was set to a minimum level and wasn't going to MAX.
Once I reset the Auto Fan speed to go to MAX, system worked fine.
It now goes to max fan and then slows down as temperature declines.