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a/c performance

8K views 43 replies 10 participants last post by  Beverly Sharp 
#1 ·
Yesterday, it was 100 degrees here in Dallas. The air temperature out of the center vents on my '01 E430 (67K) fluctuated between 48 and 50 degrees (the latter when I was stopped at a light). Shouldn't it be cooler than that? I had the system evacuated and refilled and changed all the cabin air filters, so I'm not sure what else I could do to get it cooler. Would tinted windows really help that much? Anything else? Thanks.
Beverly
 
#2 ·
Oh, another question. When I change between outside air and recirculating air, I hear no "flap closing or opening noise" (I definitely heard it close in my '96 EClass). This tech said no, you won't hear anything, but I'm skeptical about that. Anyone know for sure. If I'm getting outside air, it would seem to me that the a/c wouldn't be quite as cold as with recirculating air. Anyone know? Thanks, and thanks for being patient with me, a novice of novices.
Beverly
 
#4 ·
Yep; that's me with the Cuban cigars. Last evening, my grandson four different times blew cigar smoke into the intake (under the hood, passenger side); he waited ca. a minute between "blows" so the smell would subside before repeating. Having the recirculating switch on or off (two times each) made no difference; the smoke (mostly strong aroma) came into the car every time.

This suggests to me that the switch is not working and therefore I'm getting outside air coming into the a/c system all the time. If this is so, is the problem likely a vacuum or electrical or other problem? I may have to get my indie shop to figure it out because I'm not a "wrench and screwdriver" person.
Beverly
P.S. Grandson took the cigar home with him.
 
#5 ·
Sorry about the cigar ;)
The inlet is in the gutter, so better to do the test with hood closed.
Flap system is having terrible access, so this is not going to be simple job.
I was fortunate enough to not have the problem on W210, but on older cars owners would rather disable the flaps than spend big money for elements replacement.
The fresh air flap might be easier to reach, so check youtube and other forum is somebody did the pictorial .
 
#6 ·
Good suggestion. Since the other flaps, etc., work on the a/c system, and no-one EVER, EVER smokes, drinks, or eats in my MB, maybe I should just have my tech close the outside-air flap permanently (especially if any other fix is complicated and expensive). I'll ask him what's involved and post what he says for pro or con comments from you all . . . maybe next week, though, as I'm laid up for a coupla' days.
Beverly
 
#11 · (Edited)
lol, W210 door seals are good, but they're not THAT good. Incidentally, have you ever wondered why your ears don't pop when someone slams the door? Especially when all windows are up?

If you take off the B pillar covers, near the bottom you will find a vent, that vent's job is to diffuse the air and provide a way for the air to rush out after someone slams the door. This same vent also will induce fresh air into the cabin....albeit at significantly reduced rate. Mother MB accounts for all variables, including for leaves completely plugging the AC intake, therefore fresh air has to come from somewhere.
 
#9 ·
If you can find an Indie who understands these HVAC systems well enough to repair, you have done well.
I have both E320 and E430 low mileage cars. Each blows 40* out the center vents and sometimes 38*.
Make sure they have Star C4 !!

When trying to troubleshoot the A/C on '02 E320 I had discovered a broken swiveling coupler on brittle plastic vacuum line. The coupler costs a dollar. It was incidental to my A/C not working. I have posted photos of this before but will attach.

Trying to change it and get the actuator lever reassembled was a nightmare but I finally was able to do it. Should have taken 30 sec but access could not have been more difficult There are several more of these actuator arms that control the flaps further
up that would be impossible to change for anyone without major disassembly and likely dash removal. Horrible engineering.
You could have this exact problem.

Unfortunately these fragile parts are very cheaply made. It seems everyone with a W210 or probably any Benz has issues with A/C.
These systems are temperamental at best. Any Toyota A/C responds immediately, cools or heats better and faster typically causing no problems well over 100k... and if one shows up easy and straightforward to repair.
I would prefer a turn dial to these cheesy arrow buttons a thousand fold.

Still I have two W210 of them and love the way they look,drive, cruise, etc.

My issue turned out to be the HVAC control module itself. I had multiple bogus sensor codes, when those sensors were all good, and there was nothing obvious or anywhere on the lists that provided clarity unfortunately. The good news is that eBay has plenty of electronic modules, all you need is part #, for a tiny fraction of what new would cost. The electronic modules in these car fail, and when they do only a Star system will show the problem, and even then it requires experience to understand which module is the culprit...
 

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#13 ·
I have both E320 and E430 low mileage cars. Each blows 40* out the center vents and sometimes 38*.
Idling at a stoplight in 100°F+ weather?

If yes, I would consider that stellar A/C performance.

If you take off the B pillar covers, near the bottom you will find a vent, that vent's job is to diffuse the air and provide a way for the air to rush out after someone slams the door.
LOL. My 1964 190D had that too!
 
#10 ·
mauipaul, thanks for your reply, much info. I love my E430; it's a beautiful car, great ride and drive, etc., but it is my fifth MB and ALL OF THEM have been lousy when it comes to A/C (my '85 190 diesel was an a/c farce). I laugh when reading ads for older MBs with "ice-cold air." Right, it's ice-cold for the first three inches out of the vent, and then at about six inches, it's barely cool, and when it gets to your face, well, prepare to curse.
I'm taking it Monday to my indie shop (they're very experienced and I trust them completely) and see what they think they can do. If they can satisfy me without a mountain of money, I'll do it and also tint the windows a bit darker. But if it's a huge job and big bucks, I'm probably done with Mercedes ownership (forget disassembling the dash). Love my Benz, but I'm too old (80 now) to endure mediocre a/c through four months of HEAT in Dallas, and I mean HEAT (102 today, 106 tomorrow, up to 108 next week).
Beverly
P.S. Friends tell me to find a nice S-Class, that the a/c systems in them are more powerful and will cool better; that would be fine if it's true, but you can probably understand my skepticism. Anyone know how the S Class a/c systems really compare with E Class?
P.S. II. How is that Mercedes Benz can engineer their cars so wonderfully, yet have such piss-poor a/c systems? Well, if I've gone on too long, please excuse me---I'm going to the fridge now and get a Becks Pilsner, maybe two.
 
#12 · (Edited)
All better cars do have 1-way vents for the exhaust of cabin air.
When those are clearly visible on my pickup on back wall, MB has them in trunk.
This way the luggage in the trunk is getting some temperature control as well.
Still 1-way flapper is design for 1-way and with lack of coming air, the cabin air might not exchange.
I agree that the seals are probably not that good, but do you really want to test it?
BTW any bad seal on MB is easily detectable by wind noise.
I am just dealing with the issue on father's W124 that had door replaced after door-bender.
Both seals on the top of the door look in good condition, but slight misalignment makes noise at freeway speeds.
Probably something you would not notice on Honda with all other noises, but annoying on Mercedes.
 
#15 ·
Can't have cabin inlet under the hood as this way you'd be breathing engine fumes and that on some occasions can be lethal.
All cars have good seal before firewall that seals flow from engine bay towards the windshield so gutter/cabin inlet get fresh air above the engine.
MB often has 2 seals.
 
#19 ·
Kajtek1 says the "thing" I asked about is not the a/c inlet for fresh air, but Deplore says it is. All I can say is when my grandson blew cigar smoke into the smallish black "gutter" K mentions, no smell came inside the car; but when he blew smoke into the "thing" under the hood, the aroma (or odor, as you prefer) can strongly into the interior.

It sounds like Deplore is correct, but I can only judge on the basis of cigar smoke (not exactly a tech approach, I admit, but it seems to indicate which is correct). Again, in 100 plus outside temp, having the recirculating switch on or off doesn't make ANY difference whatsoever on the interior temp. Am I missing something here?
Beverly
 
#22 ·
I will get a picture of the part I'm talking about tomorrow when my grandson comes by to show me how to do it (computer challenged I am). The diagram is very helpful and a great source of seeing how the system works and where all the individual parts are; thanks for that. It looks to me if the evaporator ever had to be replaced, that would be the end!
B
 
#27 ·
Beverly,

Posting pics is pretty easy as long as the files are on your computer.

In the window where you type your posts, scroll down to "Additional Options" and, in the second box, click "Manage Attachments".

That will open a new window, expand that window. Click "Browse", select the file you want to post, then click "Upload" at the far right side of the window. If you're done, go to the bottom and click "Close this window".

Finish your post then post it to the forum. The pic(s) should be in your post. If you want to check it first, click "Preview Post" instead of "Submit Reply".

Fred
 
#33 ·
So...it sounds like everything is working as intended.

Though possibly both ac filter and charcoal filters will probably need replacement..... and you'll also need to take a look at the smog sensor. The sensor is supposed to automatically activate the recirculate function when it detects higher than norm pollutant in air (which cigar smoke qualifies.)
 
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