Clean those evaporators! - PeachParts Mercedes-Benz Forum

jubjub · #1 08-02-2011, 04:32 PM

Some pictures of my evap cleaning adventure. A before and after picture. It took me 2 days from start to finish. About 8-9hrs of labor.

This car (85 300d with 130k) was a southern car all of its life, so that may explain why it's dirtier than others i've seen. I don't see how cleaning from the blower motor would work in this instance. It took me a while with a water hose and coil condenser cleaner to get it shining. It almost looked like there was a slimy layer of black algae on the coils. It would also be very hard to clean the coil at the inner most (towards the tranny hump) section of the coils where all the dirt was. (Take the coil in the first picture and flip it over left to right to see where it goes in the car)

wildest · #2 08-02-2011, 04:46 PM

Since I have the same car with more mileage, that may be in my future.

1980sd · #3 08-02-2011, 04:54 PM

Good job! No worries there! Doesn't look like there was any way to do it without pulling it.

andrewjtx · #4 08-02-2011, 04:59 PM

Luckily, I have a spare A/C setup from my '84 that I can perform this on, then just take a weekend to swap out on the '85...

jubjub · #5 08-02-2011, 09:28 PM

Quote:

Originally Posted by wildest

Since I have the same car with more mileage, that may be in my future.

A combination of everything that is in the air. Soot, dust, dirt, pollen, you name it. Since there is no filter, it's sucking dirty outside air. The first layer seemed like algae. black, shiny and slimy

leathermang · #6 08-02-2011, 10:44 PM

Jubjub, That is a great service you just did.... Just in the last few weeks I have seen people say they cleaned or inspected their evaporator and they were clean... and I really suspect that between the fins it was just like yours started out...
I am sure you are correct about it being some living stuff ... as these fins are always usually wet....and warm soon after the AC is turned off... prime growing area...

mattc · #7 08-03-2011, 08:41 PM

Not knowing the specifics... ...just asking: Is it possible to drill (carefully!!!) a few strategic holes in the surrounding case, and "flood" the case with coil cleaner a few times - and maybe, do a 1/2 way decent job?
Like I mentioned earlier, I really don't know the specifics of the evapoator set-up. I'm just wondering if there is a chance this might make a substantial difference, without the time involved in removing the evaporator. The job appears to be a daunting task; not only the labor involved, but I strongly suspect some brittle-with-age plastic parts might not survive the ordeal. Any thoughts here?

JHZR2 · #8 08-03-2011, 09:36 PM

wow, pretty extreme difference there. Too bad this isnt easily donw without removing the dash and opening the AC system...

franklynb · #9 08-05-2011, 06:46 PM

Quote:

Originally Posted by mattc

Not knowing the specifics... ...just asking: Is it possible to drill (carefully!!!) a few strategic holes in the surrounding case, and "flood" the case with coil cleaner a few times - and maybe, do a 1/2 way decent job?

No. Once you've actually cleaned one, you realize it cannot be done any other way.
Sure, you can spray stuff in. It just doesn't get the coils clean. The crevices are way too tight, and the angles of attack are lousy.

Quote:

Originally Posted by mattc

...The job appears to be a daunting task; not only the labor involved, but I strongly suspect some brittle-with-age plastic parts might not survive the ordeal. Any thoughts here?

With practice, one can pull a dash in an hour; in another 15 minutes, the entire heater/A/C box is out, on the bench. I
1) pull the instrument panel
2) pop the light switch knob, parking chain, covers for the A pillars;
3) drop the steering column, 2 nuts behind the IP
4) 5? screws, and pull the dash out the right door!

record: 24 minutes.

Steering wheel is left on. It actually takes more time to get the seats, console, and
carpets out of the way -- and few people think these are "daunting tasks". A dash looks way worse that it actually is.

I've not had any problem with the plastic parts, especially on the heater. I've done 4.
All the clips released fine, even some that were rusty.

Here's a picture of the heater with the clips highlighted. I did this on the first one so I wouldn't miss any when re-assembling the unit:

<https://picasaweb.google.com/franklynb0/ACaliforniaWagon#5602556050845675714>

Here's the crap that is in the box, and the reason you'll never get a spray can to do the job:

<https://picasaweb.google.com/lh/photo/N9wjvBiAEQiw3ri2vUvNfA?feat=directlink>

here's the evap in its1/3rd box, and the reason you don't want to start drilling:

<https://picasaweb.google.com/lh/photo/3vQB7zdKP05JtzpxLUppwg?feat=directlink>

Here's the intake duct, and one more reason why spray bombs are a waste:

<https://picasaweb.google.com/lh/photo/HjA5afEXhiw97qXNLK0OCw?feat=directlink>

Even if you get the evap clean with a spray, how did you get to the intake to clean it?
behind the evap???? won't the crap just clutter it up if not removed? of course it will!

Blower box dis-assembly is a "pop the clips" 30 minute task.
15 once you've done it a couple of times. I use a parts washer to clean the
coils with a Zep product, which is slow
but enviromentally friendly.

The re-assembly goes much faster, especially the dash.

hth.

jeffr0000 · #10 08-05-2011, 07:00 PM

Freaking amazing.

JHZR2 · #11 08-05-2011, 07:24 PM

Sounds like a Spartan car... Those instructions are nice, but something tells me there is a radio, ACC, and some other wires to disconnect which take more time.

Plus to pull the evaporator, one has to evacuate and disconnect the AC, right?

franklynb · #12 08-05-2011, 08:10 PM

Quote:

Originally Posted by JHZR2

Sounds like a Spartan car... Those instructions are nice, but something tells me there is a radio, ACC, and some other wires to disconnect which take more time.

Plus to pull the evaporator, one has to evacuate and disconnect the AC, right?

Yes. Purge it, then unscrew the evap valve behind the pass'r kick panel..
A 1-1/8" and 7/8" wrench releases both A/C coolant hoses. Unplug the blower while you're there.

If you have ACC3, also unplug the blower controller and climate switch,
the bracket is mounted under the 6mm nut holding the heater to the firewall.
Its easiest to just pull the entire bracket.

If you have ACC2, I feel your pain. Knock the fat harness up over the heater.
It will make it underneath, but its very close.

Spartan?
A fully loaded '85 wagon, actually. I think its really a matter of maintaining access to all the little features that M-B planned
to make these jobs easy! A printed service manual certainly helps.

My times for dash removal assume you've had already removed the console;
which can be more or less a pain, depending upon seats, how often you've pulled the 3 self-tapping console screws, which all rust
.... and how familiar you are with the "blind removal" of the top screw and anchor system, behind the wood trim plate on post 80 cars
... and undoing the oil service line, which many dramatically over-tighten, without seeing it.
The console CAN come out without removing the seats, but its a lot easier with them out.

I have spent over an hour getting the outboard rear screw out out of a rusted drivers seat track.

The first few times I removed a lot of unneeded stuff. It is easier if the map door is removed, so I made a special screwdriver to do it quickly.
ditto the right angle reach of the screws for the speaker covers. And taking the speaker covers out without
breaking them is its own "first timer" challenge, but quite easy once you know which direction to pull.

With that written, unplugging the five switches , two connectors
and the radio harness isn't that big a deal IF you've worked on your console
such that the drivers carpet can be snapped out. 1 screw, snap,snap and the whole cover comes out of the car!
They seize on the two stuff-cinch connectors to the plastic over the years, making removing the console a pain.

If maintained, the radio can be unplugged -- and removed -- without removing the console. FWIW.It just snaps into place.

I'd say pulling a dash is easier than pulling the bracket on an R4 compressor,
to give it a comparison. Its certainly easier than changing rear axles, and a lot of
people do that. Of course,YMMV.

jubjub · #13 08-06-2011, 09:16 AM

While I don't think i'll ever be as fast as frank, I think the job can be done in 1 day. If it's your first time, just make sure to label all the wires and bolts. Take good pictures in case you forget where something went. I only had 1 extra screw and I know exactly where it goes, I just couldn't get it to fit. One of the hardest parts for me was the heater hoses. It's tough getting the hose clamps off, then trying to pry off hoses that have been on for 25 years. The aluminum tube coming from the heater core was corroded and had some large holes in it, so I had to spend some extra time 'fixing' it.

I can't see how to clean the evaporator any other way, it's just too tight and awkward in there.