Very weak defrost and floor heat - PeachParts Mercedes-Benz Forum

ksing44 · #1 12-11-2008, 07:11 PM

I have a 1995 E320. My fans seem to work fine. At least there is plenty of noise that sounds like the fans should be blowing air. I get the best flow from the side vents and I can feel that the air is warm, but there is just very little flow from the defroster and the floor vents. Even on high and with the controls set to all defroster, I don’t get much flow from the defroster at the windshield. I tried every possible setting for auto, max and low speed fan, as well as the different settings for all defrost, half and half defrost and floor, and mostly floor.

Let me see, I also have a rather loud slapping sound from something closing in the dash when I start the motor in the cold. I have had that for quite a while, even before I noticed the loss of the flow of air. I figured that was a fresh air supply vent slapping closed that limited outside air until the car warmed up a bit and maybe some foam padding had deteriorated. I did have decent air-flow in the past, even when I had the loud slapping.

Anyway, please help me understand what might be causing me to have low air flow from defroster and floor vents, even though I have a fan that sounds like it is blowing and the air seems to be warm. This is not a good situation going into a Pennsylvania winter. I just spent $1200.00 to get my front spring perches re-welded onto the car this week, so this is not a welcome surprise.

Thank you everyone,

Ken

ksing44 · #2 12-11-2008, 07:40 PM

http://www.peachparts.com/shopforum/diesel-discussion/35373-w124-climate-control-vacuum-pod-replacement.html#post197605

Unfortunately, I think mine is probably the "pods", as discussed by gsxr at the link above. I sure wish gsxr lived closer to me. I would definitely like to be his friend and get help with my W124. The slapping is probably a damaged diverter flap that may not really be causing the problem. I bet I am going to have to have the dash pulled and all of the pods replaced.

Arthur Dalton · #3 12-11-2008, 11:04 PM

First suspect for low blow airflow on 124.032 chassis is cabin air filters are plugged solid.

http://catalog.peachparts.com/ShopByVehicle.epc?q=1995-Mb-E--3--0--Sedan-Climate--Control&yearid=1995%40%401995&makeid=MB%40%40MB%40%40X&modelid=E%2D320%2D001%40%40E+320+Sedan&catid=R%40%40Climate+Control&subcatid=R2060@@ACC+Cabin+Filter&mode=PA

Reason is b/c owners don't even know they are there , so they have never been changed ...also the reason so many Blower Regulators burn up on that same chassis.....

Check them first..under hood, under WWiper arm

ksing44 · #4 12-12-2008, 03:50 AM

Thank you for the tip. I have read about the filters. They were replaced once in the past at a routine dealer service. At least there was a bill for doing the job as part of the service. That was a while ago, however, and I don't get service at the dealer anymore.

I will certainly be hoping it is the filters, so I can get away without going into the dash.

Thank you

Arthur Dalton · #5 12-12-2008, 06:52 AM

Pull them out and then turn on the blower...that will tell you right away if they are the cause of limited airflow.
Commonly overlooked item.

JimFreeh · #6 12-12-2008, 07:01 AM

If the fan motor has ever been replaced, and the squirrel cage blower wheels installed backwards, flow will be low.

Jim

Arthur Dalton · #7 12-12-2008, 07:38 AM

True, but he states ...

While you have the filters out, spin the fan by hand a make sure it spins freely...if not, clean it up and use some ATF on the bearing/bushes...the fan could be dragging and not getting up to speed. You will know more after removal of the filters.

Is that 904 paint code ???

ksing44 · #8 12-12-2008, 09:46 AM

Today I tried the re-circulation switch and it seemed to make a difference. When I went back to no re-circulation, it seemed like I was still getting the better flow from the floor vent and the defroster. If the recirculation switch temporarily solved the problem, does that give any of you a better idea of what the underlying problem might be?

On another site, someone suggested that it sounded like my main air vent wasn't opening as it should. It seems that might be something that could be controlled by the re-circulation switch. The poster also said the main air vent was accessible from under the wipers, so that again would be better than going after the pods in the dash. Do any of you have thoughts about the chance that it is the main vent, which might be controlled by the re-circulation switch?

Arthur Dalton · #9 12-12-2008, 09:50 AM

The filters are in the main intake...recirculate does not use the filters ...so, again...Check the Filters. Not saying the filters are the problem..but that is where you want to start b/c that is the easiest and most probable.
Everyone wants an answer but does not want to look........

ksing44 · #10 12-12-2008, 10:46 AM

Quote:

Originally Posted by Arthur Dalton

The filters are in the main intake...recirculate does not use the filters ...so, again...Check the Filters. Not saying the filters are the problem..but that is where you want to start b/c that is the easiest and most probable.
Everyone wants an answer but does not want to look........

I am planning to change the filters, regardless of the cause of the problem because I’m sure they could use the change. I just have a feeling that the underlying cause of the problem might not be the filters, since the issue seemed to show up suddenly. It is possible that I just didn’t notice a more or less gradual loss of flow, with not really needing heat until recently, but it just seemed like a sudden acute failure of some kind. I will definitely check the filters and anything else that is accessible from the wiper side of the system. For example, it will give me a chance to change the squeaky fan motor, or at least get some lube on the thing.

Bye the way, do you think the re-circulation switch bypasses the filters? It seems that it could, since the engineers may have figured you wouldn’t need to filter the air that is already in the car.

Arthur Dalton · #11 12-12-2008, 10:56 AM

I have done many of those filters and they are way up on top, so I do not see a way for cabin air to recirclate back up to that point....the next generation of E320 [ 210 chassis] did away with them and actually put them in the cabin [ under glove box area] so that they would still filter cabin air regardless of recirc or not ..they also added a charcoal filter , which yours does not have ...yours are simply paper intake dust air filters .
If you take them out . see of there is a flapper there for recir., but I don't remember ever seeing any ....
There is a DIYer tutorial in the archieves for changing them...not a bad job once you do one...I suspect yours are clogged b/c every one I ever did was full of dirt and leaves. etc. ....prolly due to their under hood location ...not a real good set-up compared to the later chassis.
Like I said, may not be the filters, but I would definately look there First.....
Sure would be a lot of work if you dive into that dash only to find out later it was just restricted intake air b/c of a couple of dirty filters.....ya kno' ??

Again, is that 904????

ksing44 · #12 12-12-2008, 11:44 AM

Quote:

Originally Posted by Arthur Dalton

Again, is that 904????

Sorry, I didn't see the question. I am also sorry, because I don't know the code. My car color is "Azure Blue", whatever code that is.

My car is also a "Special Edition", with the stainless doorsills, but I only use the stock Special Edition wheels for snow tires. It is a pretty car, as you will see below. Unfortunately one of my front spring perches failed last week and it cost about $1000.00 to have both front perches rewelded. It sounds like that is more common on the W210 than the W124, but my Indy said he has seen 4 or 5 himself in his shop. Luckily I wasn’t killed when the spring fell out on the ground and the car fell down onto the right front wheel. I was going very slow when the perch failed. Now it is the heater and defroster. Bye the way, I also have a leaky head gasket and front timing cover, a bit of a shift flair in 3rd to 4th gear shifts, a leaky AC compressor, and I have not yet replaced my wiring harness. I am accumulating some problems, but I do still love the car.

Arthur Dalton · #13 12-12-2008, 11:51 AM

It is Identical to one I own , except mine is 904 Midnight Blue...same interior. The pic looks like the Midnight , but pictures will fool the eye.

You may get rid of that flair with a simple modulator adjustment...and a filter change.
I have never seen a bad perch on a 124 , but I guess that theory is now shot. Was it rust ?? ..and were on the perch did it let go ?
Was there any sag pre-failure ?

ksing44 · #14 12-12-2008, 01:54 PM

Quote:

Originally Posted by Arthur Dalton

It is Identical to one I own , except mine is 904 Midnight Blue...same interior. The pic looks like the Midnight , but pictures will fool the eye.

The midnight an azure blues do look similar in photos. In person, they also both look great, although there is a clear difference. For one thing, I think the midnight blue cars I’ve seen did not appear to be metallic. In addition, the azure is a bit lighter and seems to have a bigger tendency to change shades of color depending on the light.

Quote:

Originally Posted by Arthur Dalton

You may get rid of that flair with a simple modulator adjustment...and a filter change. ?

Actually, my flair developed after a fluid and filter change that was done when I had a check engine light come on for a faulty kickdown actuator. They also did all of the seals “while they were in there”, which I now realize was stupid to do since I have a leak free trans that will need to be rebuilt anyway. This is the main reason I gave up on the dealer. After they did the work and I had the flair, they told me I needed a transmission for $5000.00. They never said anything about the vacuum modulator adjustment.

I played with the vacuum modulator myself and also played with the bowden cable to try to minimize the flair. I learned about that on this forum. It helped, although the firmer shifts don’t really feel that great. At first I thought I liked the firmer shifts. It was like a racecar, but now I wonder if the firm shifts may be contributing to an earlier total transmission failure. I had to choose between firmer shifting or the flair. The flair can’t be good for the transmission either, so I am staying with the firm shifts. I am very careful about using reverse, since I was told that the reverse is most likely to fail and the pressures there can be considerable if you crank up the modulator too much. I only went about a half of a turn. I have my fingers crossed.

Quote:

Originally Posted by Arthur Dalton

I have never seen a bad perch on a 124 , but I guess that theory is now shot. Was it rust ?? ..and were on the perch did it let go ?
Was there any sag pre-failure ?

I do think I was seeing some sag. I thought it was due to a leaky Bilstein HD shock, which has now been replaced with my original shocks. I guess I will try to get the HD shock fixed under warranty, although I am considering getting all new Sports. My car is lowered by about 1 inch, which is an intermediate drop and supposedly ok for either the HD or Sport shocks. I just wonder now if the slightly lowered stance contributed to the HD shock failure. I also wonder if the stiffer Eibach springs may have contributed to the perch failure. The firmer springs certainly were not providing the same level of “spring” to protect the perch. Like a lot of things about these cars, many folks doing the mods really have not owned the cars for years and years and years. I have had my car for about 12 years and it has been lowered for about 6 or 7 of those years

ksing44 · #15 12-12-2008, 05:40 PM

I just drove home from work in my car and played with all of the settings quite a bit. I don’t think my airflow is great, although it seems better than last night and since I played with the recirculation switch.

Now, however, I am wondering if the real problem is that the temperature of the air isn’t as hot as it was in the past. Could my air temperature decrease? If so, what would cause the problem? I think I have read things about heater cores going bad. I will have to do some searching on that, but I thought it wouldn’t hurt to ask.

I can also test the temperature coming from a vent, like I have done for the AC. Do you know what temperature the heated air should be coming out of the vents?

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