Best free improvement for the 300D W123
 

I made a modification to my '85 300D that I think is probably one of the best free mods you can make on the 300D with the automatic climate control system. I totally removed the damper door and vacuum actuator for the center vents in the dash. The dash does have to be off to make this mod but in my opinion it should have been done like this from the factory. If I want the center dash vents closed I will do it manually:) using the dash vents. You do have to make sure they work. Works great and is free:).

I took the vacuum hose that went to the center vent vacuum pod and put it straight to the 1/2 section of the defrost vacuum pod. Not sure what it's purpose is but the system works great.

Thank you! It's nice to know I'm not alone in my quest for heated air for my hands and face. I wear pants, socks and shoes when I drive, not gloves and a mask :p

I've been contemplating reversing the spring in the center vent pod since you don't have to pull the dash of the SDL to do that much. And as you say there's a lever to manually shut the center vents.

Sixto
87 300SDL

My main drive was to make sure that I can always make cold are blow out those babies. I don't worry that much about the heat. I did notice that when I want the heat or defrost and those particular damper doors open there is not that much force out of the open center dash vents and again - you can shut it off all the way with the manual shutters. The 126 is the same except for the difference in the way you shut if off.

engatwork,

can you explain a little more what you did and what your car does now after it. it sounds interesting. i just want to understand what you achieved. do you still have appropriate A/c and heat when you want them??

I simply disabled my center vents by removing the actuator and plugging the lines. Big hands = big trouble. You need to squeeze in there to get it out (without removing dash).

Now that's almost worth pulling the dash for.

I want only COLD (fresh) air coming from that vent.

I'll have to do that for my SDL. I can replace the rubber vacuum pod diaphrams at the same time.

Yes, I like warm air for my hands too, but don't you get a FFFFFFFF sound when you close up the jets?

Does this mod allow heated air to come out in the winter and A/C cooled air to come out in the summer? Like most other cars? I have never had one of these appart to see with my own eyes yet.

yes.

cool.....that is what aggrivates me most about the car....no hot or cold air from the center vents when I want it... I like to direct the other vents at the windows to keep them clear on short trips.

I wonder if this would work on my SD. And if I could achieve the same effect by plugging the vacuum line to the center pod and wiring the center vent door open?

Ahh, the joys of a "simple" 240D. No vacuum here, all manual slides. :D

Pete keep in mind that the center vacuum pod is fail shut. That means that the vacuum pod is spring loaded whereas without vacuum on it it is going to hold the damper door shut (which is what makes me want it out of there). You will physically have to disconnect the vacuum pod from the damper door and then plug the vac line.

83/300SD - I have noticed that with either the defrost open or the footwell open then the force of the air making it to the center vents is so insignificant that there is absolutely no noise at this location with them shut in heat or defrost mode.

I believe there are a few free mods that should qualify.

1: Get the boost up to spec (12-13psi)
2: Disable the EGR and clean out the intake
3: Adjust the ALDA
4: Fine tune the tranny shift points and firmness to your preference
5: Disable the seatbelt buzzer

All these are free (from cost, not labor) and will result in a fine-tuned car that you will enjoy driving even more.

by "wire open" I meant put some picture wire around the linkage and pull the door open against the spring force and then tie it down. If this could be done by sneaking a wire through the right place and not taking the dash off to do it, I'd be all for it.

Pete,

It can be done on a SD. I did it last summer. Pulling the passenger side console cover, the center vents, the stereo, ACC, small hands and some patience will do the trick. It is my second favorite modification. The 2.47 differential being the first, but it was quite a bit more expensive.

Tom

nice, Tom. So tell me, do you remember where you fastened the wire or whatever it is that you used? Are the center vents hard to remove? I know that everything else is easy. I even have the small hands, a blessing that I never knew I had until I was an adult.

Maybe my 300SD is broken??? but as far as I know...I can get heat out of any vents I want, any temp, without having to mod anything?

If I put it on the center button (vents/floor heat) I get just that...when I put it on the next one to the left I get a little vent...a little floor...and some window defrost.

The drivers vent seems to ALWAYS put out heat when in heat mode...just enough to keep my hands from freezing. :)

Normally the two center vents shut off when the system is in heat mode, and only open to supply fresh air or AC. Maybe someone has already modified yours?

Pete,

The center vents are retained by a couple of little spring clip-type fasteners on each side of the individual vent. Pry back the clips with a small screwdriver, one side at a time and the vent should pop out. As I recall, behind the vents is a rubber boot that actually covers the center vent pod. Remove the boot and you are there.

Edit: I am trying to think of the details here and one other step comes to mind. Move the center console out of the way toward the steering wheel. I believe there are two philips screws at the top of the center console behind where the top of the ACC unit was located. Remove those and the wood surround of the shifter and one screw at the back of the console and you should be able to pivot the console to the steering wheel and plastic tie it out of the way. I took the pink diaphragm housing off the pod and wired the remaining actuating arm to something under the console to permanently keep it open. Sorry for the piecemeal way I am presenting this, but I AM 56 years old and my mind is going.

Tom

Thanks Tom. That's the type of info I needed.

The way I have done this on a 300D without pulling the dash is to remove the glovebox and both side kick panels, remove the rubber boot that ties the dash pods to the evap housing and remove the "pin" that is holding the vac pod arm to the damper door then after the vac pod arm has extended out from spring pressure jam the damper door open underneath the arm. Don't forget to plug the vacuum line after removing it from the pod.

Perhaps!

I don't have floor heat very strong on the passenger side (ie none) and I think I have a bad pod causing that...I have replacements :)

Its so cold over there lately that when I take a right turn..I feel it come up over the center console past my hand on the shifter and onto my leg. BRRR!!

Ouch, I really like the ACC when it's working correctly, but what a PITA when it acts up.

Screw the passengers...I have heat!

Not sure why my center vents blow heat though...it sure is nice...I can shut them off if I want to.

Also, my rear vent still blows nice fresh outside air in heat mode...so it must not be that messed up. Iono...

You must be single.:D

There is a devoious plan behind giving the passenger no heat...

...I think that is all I have to say. :D ;)

Thos Cheap 240D(s) already have it that way !
 

My 1980 240D with it's strictly manual heat & A/C came with manual control for these two vents... a single slide lever... and the luvers are NOT adjustable!

I'm also recent owner of a 1980 300D which has the auto "Environmental" control system... so I noticed that www.**************.Com has some kind of manual conversion for the heat portion of this auto system.

Just thought I would throw this into the mix!
Sam

Speaking of A/C pods...



Do you need to replace them all at once or can you purchase them seperate? I need to get them for my SD here soon...

Replace the ones that are inoperative and you can't get to with the dash in place.

After about 5 months with this arrangement (although I don't drive the car much) I still am very happy with this mod. Nothing like getting ice cold air out of all the dash vents on these cars:).

middle vents don't work for anything
 

Is there a way to get the middle vents to work? I have no/very little air coming out of only the middle.