I took the blower motor out today to clean the evaporator on my 87 300d turbo and found something very interesting. The blower is all the way outside the car, the evaporator seats right against the firewall and the blower pushes air againts it. My question is, if the blower is outside the car how the hell does it recirculate the air inside the car, common wisdom says you can't, unless there's something I don't know. I'll like the engineers to explain that one. All a/c guys out there enlighten me.

We are going to need pictures of the fan from all sides...and the place it mounts to the firewall before you award you any prizes for figuring this out....
A Squirrel cage fan is very efficient compared to regular fans...so you may not have noticed the channel for the intake of air going to it's middle...

There is a huge door which blocks the fresh air intake. It's operated by two vacuum elements. Both vacuum elements are dual stage. Applying vacuum to only one stage closes the door most of the way, resulting in ~80% recirculation. Applying vacuum to both stages closes the door all the way, completely shutting off outside air. Trust me, it works.

On an early 124 you can see the big 'ol door by pulling the glovebox and using a mityvac to operate the vacuum elements. I guess it could be done on a late 124 as well, but you'd need to pull the passenger airbag.

I would bet many 124 cooling complaints would trace to failure of the vacuum elements. The 2nd stage seems to fail much earlier and more frequently than the main stage. So many cars are running around with only 80% recirc operating. Getting to 100% makes a big difference.

- JimY

leathermang
I'll try to get you some pics

Jimmy
I know what u are saying but the area that I'm talking about has no doors, the only thing behind that blower motor is the air intake grille that sits just under the wiper arm and covers the wiper motor assembly. I will get pics for everybody so you all can see.

Yes but once it is back together, there is a shroud around the whole thing that connects to the fresh air door that Jim described.

Have a great day,