I work for Mercedes-Benz and one negative about the product is the air conditioning. In a lot of American and Japanese cars I have noticed that the air blows cold right away. But with the Mercedes, it takes a minute or two to actually kick in. I have never heard a good explanation as to why this is, so I am hoping that I can get some help here to have a better understanding of my product. So…
Does anyone know why the air conditioning for Mercedes takes so long to kick in?
WAG The compressor/condenser has to build up a supply of refrigerant before opening the expansion valve.
If you work at a dealership go to the shop and ask the A/C technician. If he doesn’t know you’l have to email the engineering dept.
Or wait for a knowledgable owner to post the answer.
We have asked technicians here and they have NO freaking clue. I mean, they act like they do and give their theory on why, but that is basically it.
Ask these guys, if the Dope won’t hook you up:
A minute or two before the air is cold, or a minute or two before it blows at all?
If it’s the latter, it was probably designed that way to avoid the possibility of starting out with a blast of warm air. There are some luxury cars whose climate control systems are designed so that no air blows out of the heater/defroster until the car warms up to a certain point. This is so that you won’t turn the heater on and get cold air blowing on you. It strikes me as quite plausible that Mercedes used the same reasoning with their A/C operation.
Before it blows cold. Keep in mind I am in South Florida, and these cars get HOT.
Thanks, I will (assuming I get nothing here).
A couple of things come to mind.
First off many cars have a delay bulit in to the A/C compressor circuit. They delay the compessor start for 5-15 seconds after engine start to allow the engine idle to stabilize. You won’t get any cold until the compressor is on. If another brand does not have a compressor delay, it will produce cold air sooner, but at the risk of an engine stall when the compressor kicks in for the first time.
Next there is the fact that the evaporator has to get cold first. Depending on the size of the system, and refridgeant flow rate, it can take longer in one car than another.
The last thing that comes to mind is the flap settings in the climate system. If they have a default setting (vacuum controlled flaps for instance) that has the heater core open, the system will have to close the heat flaps, and open the cool flaps (Or move a blend door) to get cool air.
By the way, is your “a minute or two” literally 60 to 120 seconds, or is that figurative?
Could you arrange a one-week test drive of an S600 for me? I’d be glad to perform instrumented testing…
Seriously, have you sat down, looked at your watch before starting and timed the wait until the car makes with the AC?
Mr. Slant brings up a good point.
comparing the heat load in a car that has been parked in the sun all day, with one that the customer just drove up in 5 minutes ago is an apples to kumquats comparsion.
The heat load is not even going to be close.
A friend of mine claims this is one of the traits of all German cars (maybe just German luxury cars), not just Mercedes. Not only is the air conditoner generally slow to get cold, it also never gets cold enough (for him).
My limited experience with German cars tends to agree with that observation. I never heard a good explanation for why.
Arjuna34
I have never driven a car which didn’t take a minute or two for the A/C to get cold.
Are there cars that are immediately cold?
I want one!
-FrL-
Every car I’ve driven has cold air within a few seconds. Once the hot air is purged from the ducts the cold follows right behind it. Heat on the other hand…
Weird…
I’ll pay attention and see if my memory doth not exaggerate.
-FrL-
No, it is really an actual minute, not including how long it takes for the car to actually get cold (because of the Florida heat). It is a big joke around here for the Mercedes salespeople, where most will actually get the car for the customer so the car gets cool enough for the client to get in (and perhaps not see how long it takes).
S600, sure no problem. Come on in.
*A friend of mine claims this is one of the traits of all German cars (maybe just German luxury cars), not just Mercedes. Not only is the air conditoner generally slow to get cold, it also never gets cold enough (for him).
My limited experience with German cars tends to agree with that observation. I never heard a good explanation for why.*
My WAG (since I’m not a carmaker) is that’s because A/C isn’t that common or important a feature in Germany, generally. I.e. private houses usually don’t have A/C installed, and lots of offices don’t have, either (despite their bad insulation.) If the summer gets hot, people turn on portable ventilators, and that’s about it, usually. In the 80s, big shops had A/C in the summer to lower the temp from 30 C to 20 C, but many people didn’t like this (it meant putting on a jacket inside because it was too cool), and the big diff. in temp. meant stress for the body, so people caught “summer colds”. (Also, A/C helps spread germs, because of the condensation and moisture, which helps the buggers to breed, and then a nice air flow directs them everywhere - so not only the customers got sick, but the employees also.) So because of this, most shops no longer have A/C on in the summer, or only a little bit. (The last very hot summer, it was difficult to shop, with over 30 C outside, and almost as hot inside in the stores.)
So, for most car drivers until recently, A/C was a luxury (paid extra), not a necessity - not every summer is sweltering hot, and even then, it’s only a few weeks, so buck it up, and it wastes gasoline/energy is the general opinion. Studies that show that a cool car helps the driver to concentrate have spread A/C a bit further, but I would think it’s still not important enough to have a cool car right away vs. waiting 1 or 2 minutes - it’s whether it’s cooled or not at all that makes the diff.
Heh. If you were on the Gulf Coast side, I’d take you up on that, but the closest I’ll be getting any time soon is my grandfather’s place on a little island about halfway down the west coast of Florida.
Then again, in the parallel universe where I could afford even the GAS for an S600, I might own the business next door to your dealership, so…
As an aside, this is exactly how I remember the AC from my '78 Mercedes 240D being… slow to start, steady, and not enough to keep my back from sweating against the MB-Tex seat in North Carolina in August.
Exactly, it is like Mercedes does it on purpose, but there has to be a reason for it.
I have a 300E and my mechanic says all the Mercedes evaporators are simply too small. Another common problem is the vacuum controlled temperature blend doors can be slow to open if the vacuum control module needs to be replaced. I’d say my A/C can cool the air about 20-25 degrees. On a 100 degree day, that means my A/C is putting out 75-80 degree air which feels cool, but nothing near cold and it does take a minute or so to start blowing cool.