AC Evaporator core replacement on 92 400E
 

Okay, I finally broke down and started the disassembly process on my 92 400E to fix the dreaded Leaking Evaporator core. Yesterday I remove the Passenger Air bag and lower dash, the Driver lower dash,the complete center console, AC controller, Radio etc., all air vents and am up to the Instrument panel. Will hopefully do that tonight. Wish me continued success and patience to go slowly and no break anything. Can some give me the secret to removing the instrument cluster??

The inst cluster should just push out from the back or pull out from the front if you can get the proper hooks to attach to it to pull it. Not sure if this one has a speedo cable or electronics but I know on the W123 you can go to the speedo cable at the tranny and disconnect it to get some slack on the cable to allow you to pull it out a little further to get you hand behind it and unscrew the cable.

I'd think that since you have the lower part of the dash removed on the driver side, you should be able to reach up and push it out from the back.

Gilly

Evaporator core replacement
 

Okay got he instrument cluster out....was a snap as Gilly stated.
Removed the crossmember and will be taking out the Heater Box on Wednesday. Got class tomm. Should be down to the Evaporator core by the Weekend

I will be thinking of you. Replacing the core on my 93 was without a doubt the most exhausting automotive experience I've had in some 35 years. Getting everything back in right and tight seemed endless. Perhaps it was my aging bod stuggling in odd positions. Good luck. It was great when it was over.

Re: Evaporator core replacement
 

I don't think you're supposed to remove that crossmember are you? Isn't there a danger of the windshield cracking or something?:eek:

Only if you lift the vehicle.....I think
 

You pretty much have to remove it. The heater Box is secured to it. Maybe you remove it(the Box) and then put it back or something. Anyway, my car is securely on terra firma and it ain't moving till I get all the guts back in. I'll have to do as J.Hidalgo and others have done and drive the car to an A/C shop (partially disassembled to confirm that there are no leaks. O' Boy I can't wait to see the look on their faces when they look inside and see the dash....:eek: :confused: :rolleyes: :(

I remember the look on my face when I saw MY car down to the airbox when I replaced my vacuum elements!!:eek: I thought, "what the hell have I done?"

Are you taking . . .
 

any pictures? Probably would be nice to look back and see what you got yourself into.

Also did you consider trying a 'leak sealer' such as Super Leak Pro first? http://www.cliplight.com/ssp.php#Distributors

I use it recently and if there was a leak in the evap, it fixed it.

No pics yet but.....
 

I may do a documentary as I put it back together. I'm waiting to see how hard it really is before I post a step by step on the process. To this point it really hasn't been too bad. Just taking my time and not being in a rush is making all the difference in the world. I'm working out of my garage and even with the car doors open and the garage door open with an attic vent fan, its still HOT and don't even talk about the humidity. 5 minutes into the process, I'm dripping wet. So I have to wait till it gets cooler..~7:00 but then I'm in a time crunch.

Good luck with the project.

I am currently having the evaporator replaced in the E500.

best regards
-fad

Albert,
 

I did take my car to an A/C shop after I replaced the evaporator AND put everything back together. If you notice, the evaporator inlet and oulet is located in the engine compartment by the firewall, on the drivers side. So, my logic was, if you have a leak, it would be outside the dash or, in other words, "reachable". If your evaporator is new, I would not worry about leaks or, you can pressure test it BEFORE you install it. Do check ALL the vacuum lines under the dash to include the "pods" and replace them while you are there.
Did you remove the steering wheel?
Good luck!

I got to throw this in, your windshield wont crack with the crossmember out ( unless) you lift the car on a rack, then you have problems. Make sure you replace the vacuum elements unless ya wanna go back in later. Evaporator on the 124 is one of the easiest just take your time and you may wanna throw some new bulbs in the illumination since your there. Good luck.:D

Erik, check you PM's or send me one. I need to ask you something.

Thanks
 

Thanks J.H....I did not remove the steering wheel per your/others instructions.
Thanks Koonce, I was going to bring it out to BR to have you do the job, we spoke about bring it out one weekend and doing a lay over in BR for a 1 day repair. The price was definitely right since I do have(had them for 10 months now) my parts already. Then i got this guy, a tech at a local MB store that said he could do it for a pretty good price here at my home. I thought great, no drive, a weekend project and $500-600 csh to the guy Tax free...Win-Win. But he stalled and stalled and stalled.....Then it got hot about 2 weeks ago. Then I got HOT:mad: and said the hell with it all. I'll do it myself. And so I shall. So far I gotta tell ya, it ain't that bad. Unless the hard part starts at removing the heater box and ultimately the Evap core itself. Please tell me its all pretty much straightforward from here on out and that the rest will not put up any particular resistance... Please, Pretty Please.........:rolleyes:

I stopped by Smythe European to visit my E500 last night (evaporator replacement)

...it was a chilling sight to see the frontal dash area completely apart!

-fad

Smythe European
 

Hey fad,
What'd them boys at Smythe European charge you for the "surgery".

Hey Albert -

I'm following your post with interest...I'm contemplating replacing the evap on my 300E...let us know how it all goes. Thx!

Not bad
 

Well Zeus, honestly as I stated down to where i am is really straignt forward. The old wrench was getting the front speaker through the dash assy. The speaker are soldered to the wire. So I had to turn them sideways(perpendicular) and make them go back through the hole. The passenger side airbag was straightforward too once I understood that there was a long bolt that you access through a hole in the passender side lower sub dash assy. If your's is a 93+E you can feel the hold by rubbing your hand under that panel. i've disassembled the blow assy before so that will be a piece of cake. I do already hace all the parts...Evap core/exp valve , dryer, Hi/Lo switch , (6-7)actuators etc. I'll detail all when I get to the Evap. core and add pics as I do the rebuild.
**No special tool needed other than the Radio"keys". I've been using mostly a philips screw driver, an 8mm nut driver and a 10mm wrench to remove the crossmember. As i said pretty basic stuff..... To make sure that I remember which screw came out of and goes where I reinserted them back into the piece/area that they can from and used masking tape on the thread side to keep them in place. I had to put the airbag inner backets in a bag and the crossmember nuts in a bag(ziploc sandwich bags) as well as the speaker grill and the dash screw thats under the grill in bags as well.....But I'll detail it all this weekend maybe. I'm just nickeling and diming the process. this weekend I'll give you my, "If I been on vacation and was dedicating straight time to it, how much time would it really have taken." Others have mentioned that the dash can be disassembled and reassembled in a 4 hr span. So I trust their estimate on that.

Stay tuned

Greetings Albert- -

surgury charges= $ open ticket.

Do you go to the doctor and predicate your care on the cost of that MD's service and/or with a $ limit?:D

all kidding aside- I'll share when all the work is completed-- - also having upper engine wiring harness upgraded now

most people that I've spoken to regarding this job acknowledge that it is a time consuming job and ends up in the area of $3k (including new evaporator part)...I'm not sure if that figure is accurate to 2003 $ though

-fad

Thanks Albert, you're inspiring me. ;)

I've got an '89 300E, with only the steering wheel airbag. I'll keep tuned to your post, looking forward to hearing how it all goes. If I decide to do it, it will be within the next month or two, when I get a free long weekend.

Zeus,
 

Be aware a long weekend may become a LONG WEEKEND. You may plan ahead with another mean of transportation is that is your only one.;) for those unforseen circumstances...
Just a friendly advice!

Believe me, the 400E is NOT Alberts only transportation. As a matter of fact, I fully expect that he has the 400E torn apart so that he has a good excuse to drive the most beautiful 500E I've ever seen.

He said in another thread that he would be doing a few hours work here and a few hours work there on the 400E. I fully expect that is a further addition to his plan, so he can get plenty of time with his Red Wonder.:D

Have a great day,

Hi - Ho RED-E....Away!
 

Amen Larry. I'm not at all bothered by the 400E being torn down. I do have the luxury of another 2 cars.(My wife's 5 series BMW wagon) . So I have plenty of wheels to get around in. I do absolutely adore the 500E, but my 400E is my main squeeze:D . The 500E will forever be my "Mistress" as my wife likes to call her, but she knows(both the 500E and my Wife) that the 400E is my girl!..... But J. is absolutely correct. You try to do this job in a weekend and it will be a REAL long, time consuming weekend. Its not hard, so don't be discouraged Zeus et.al., but it does take a LOT of time taking off this then that, then reading then taking off some more. Then finding a hidden screw that's holding something on. Then resting, wiping your tired weary brow and then celebrating that I FINALLY GOT THE DAMN THING OUT!!!!!!!!!!
I got a little careless and cracked a piece of the airbox so I'll have to epoxy it. Went to the dealer to see if they see just sold the piece that goes down to the Dr. side floor vent and they said that the entire box comes as a unit..$2200. :eek: Needless to say, I'm super glueing/epoxying it back together. It really is a small insignificant crack so what the hell.So far that's been my only snaffoo! So the Box is out and I'll take it apart on Sat PM or Sunday AM - PM R/R and put the box back together. Father Day what I want from my wife/kids is a weekend of freetime to reassemble the beast. So that's what I'll ask for and will hopefull have her back on her feet by then. As I said I am taking career enhancement classes and what with my 8-5 plus study time daily for the short summer semester and time due the Wife/kids, I end up having to "steal" time to work on the car. But I ain't complaining. Like Larry pointed out, every one should be so(UN)lucky as to have their main ride "down" and then have a trusty steed that you can mount just waiting in the wings all gassed up/waxed up/ dressed up and ready to GOOOOOOOOOOOOOOO!:D :D :D

Albert,

fyi according to my Service Advisor the Repair Order currently amounts to (parts only) $3300:

>upper engine wiring harness
>evaporator replacement (seals, expansion valve, R134a, etc.)
>valve cover gasket

(does not include incoming complete rear window sunshade replacement/ ordered and expected next week from Germany)

best regards
-fad

Still a good price
 

To Stating the obvious, make sure that they are replacing the actuators. They generally do as a matter of principle. I know you'll be glad to get 'er back. I certainly will be glad to get the 'ol gal back on her feet in the coming days/week. The thing is one I do the 400E and everything check out, I still need to do the 500E. The Core on it which was replaced last year, developed a leak. And since I provided the part, the replacement is on my (d/t)ime. But the way the job is going, I don't give a S#!t. I know my way around these cars pretty well, its just fear of the unknown. If you were to slap a "Bowtie" or a "Blue Oval" on these darn car, I'd be all over it in a minute. I just need to get over the stigma of it being a very expensive and delicate piece of machinery and just treat it like what it is....... a very expensive and delicate piece of machinery !!:eek:

Got the Evap core out
 

Okay, So i opened the "Box" and removed the old evap core and put the new one in. there's also a small piece of screen that covers the evap core that you remove from the old and replace on the new. I sealed up the box and will put it back into the car sometime next week. I lost a few of those little clips that keep the box together. No big deal. I also broke another little internal gizmo, when I accidently cracked the left floor vent assy. All in all everything is going well.
(I epoxied the left side and replaced the clips and reinstalled the box)

Its Finished
 

You know how when it reains it pours.... I have 3 cars. The 2 MB's + a BMW. I took the 400E out of commmission while doing the AC job. Then last week the Tranny Blew out on the 500E. Then the fuel pump went out on the BMW. Strike 3 - I was out.(No more cars...walking, riding the bus, thumb in the air etc.)
FORTUNATELY, I had already begun the reassy process on the 400E. I already had the evap. core/ heater box, the windshield assy and rec/dryer reinstalled in the car. So basically all I was really tackling was the interior stuff. Guys I gotta tell ya, the job really ain't that bad. Yeah I know it took me a month, but I just didn't have time to fool with it. And as I stated at the top, when I had the time, I was waiting on this clown to see if he was going to do it. I am SO glad that he did NOT do it. Now I have the "know how" to perform this task again, perhaps aide any of you who might be undertaking this task in the future. So anyway. I reinstalled all the interior pieces. The hardest part was getting the upper dash to mount over the two upper blow vents on the AC/Heater box. After that it was "knit one/pearl two." I drove the car to the dealer to get the seals for the receiver dryer lines and while attempting to help this guy who had a busted tensioner for a 400E, I met and began to talk to one of the tech's who was there slumming on Sat. Long story short, we rolled the car into the shop and I got the "Homeboy Hookup" on the evac/recharge for get this.....are you ready..you're not gonna believe this.....$30....For evac/ reharge / oil AND Freon(134). TOLD you, you weren't gonna believe it. Plus I got his phone number and asked if I need him for a big job, if he'd be interested. He said yes. He also knew the other clown and when I told him my plight, he said that the guy was having some problems. I said yeah tell me about it. So that'st. I'm chillin like a villian.:cool:
Gotta do the Fuel pump on the BMW today and will hopefully get the 500E back by the weekend.

Job total(~$800 for the Core, the actuators, the recv dryer and the Hi/Lo pressure switch.including HomeBoy Hookup on Evac/Recharge)....I saved $900-$1000 in Labor....Cha - Ching!!
Not having to sweat the job if I ever have to do it again....priceless
**Tip** I let the steering wheel ALL the way out and left it intact.
where possible reinsert the screws in the removed pieces and wrap tape arount the threads. This way you'll know the exact screw that came out. Label parts pieces and connectors with tape and make marking on the connectors so that you'll know which one was the left / right. Put other pieces/screws in ziplock bags. Write on the bag where they go or put a note inside the bag telling where they go. Take photos with Digi or regular cam. Print off entire procedure from MB CD's and make notes if you need to on the sheets. (The tech said that there are seals in the Heater core that they replace when they do the job.. he said that the intake and outlet tubes are removable to access these seals. I do not remember the heater core having said joints. Any way if you do the job and there are seals, R/R them)

Way to go Albert. It makes the instrument cluster removal/installation look easy now doesn't it:).

Congratulations Albert!
 

I am glad everything worked out for you. The sense of accomplishment is priceless but, the money you save makes you feel even better.:D
Right now, I am in the middle of head gasket/valve, so far so good...

A job well done
 

I want to thank the well wishers before during and after the job. It was rally a labour of love. I encourage any/all of us who needs this job done, and you have the space / time........ to DIY. get the parts fron Phil...(He's the man).Absolutely NO special tools required. I have a prety good set of craftsman and a cheapo $20 set of "Companion"(Sears bottom of the line Taiwan) tools. Which includes 1/4 and 3/8 drive ratchets/ SAE& metric sockets and wrenches 1/4-9/16 and 7-15 , phillips/flat screwdrivers . I used the COMPANIONS and they were all I needed!!!! So surely each of us has at the very minimum a COMPLETE set of cheapo tools. If you don't go out a buy yourself a BAD @$$ set with the $1000 you'll save by DIY. :D

Thanks for the inspiration Albert!
I look with less dread on this task.

The 95 wagon is now on 116,000, with nothing having gone wrong yet. But...I feel like there is a really large ticking clock hovering over me these days. So far no major problems.

Once, a while ago, I had to replace a heater core on a '65 Riveria I owned and restored...I won't say more, except that it is a very similar project, but with all metal parts everywhere, no plastic! Oh man, was that painful. And yes of course, didn't I have to do it in the middle of August.

Someone in the Riviera owners association figured out a way to actually cut out a re-closable opening in the firewall to remove the core/evap., that's how desperate some people were getting; but I didn't do that, afraid to make a bad situation worse.

I had the dash apart to replace all the HVAC vaccuum elements, however, there was no leak in the 1988 wagon's evaporator!

So I'll just wait for the leak.

BTW: since the evaporator and condenser for a R12 and R134a W124 use the same replacement parts, given that I've replaced these parts and have converted to R134a, do I fill to the specs of the W124 R134a label or is it still 80% of the W124 R12 label?

Also, I'm thinking about going back to R12 since I'm moving to Florida. Is it worth it? Can it be done WITHOUT a new compressor

I'd replace receiver/dryer, pressure switch, and expansion valve, flush the system, drain the compressor of PAG46 oil, and hold a vaccuum for 1-2 days, and change out the O-rings back to R12.

New Thread
 

Hello Neil, This is a deep thread and should be entered as a new thread all on its own. Larry Bible , Steve or Donnie would better be able to answer it. I agree with your thinking/logic, but this is best answered by the experts

Albert,

Not only do I congratulate you on a job well done but thank you for posting the blow by blows here on the site to share with us.

Actually, the truth be known, I think you're just a wimp when it comes to the mild Houston summers so you had to get it done quick.:D

Seriously, I've spent enough time in Houston in the summer to understand the need for the a/c. I lived in dry Lubbock as a teenager and when we came to Dallas in the summer it just killed us because of the humidity. You go from Dallas, with moderate humidity, to Houston and there's that much MORE difference. The heat and humidity is absolutely brutal.

I know what you mean about the feeling of accomplishment after you've done something like this. After you've been there and done that then you know that you can repeat the job and its great to have that confidence.

That said, my 124 evaporator is still holding tight. MAYBE I'll dodge the bullet altogether. If it starts leaking though, I'll just drop it by your place and use the 500E 'til you're done.:D :D :D

Hope to see you again soon,

ke6dcj,

If I were you I would go back to R12. BTW, yes 80 to 85% of the R12 quantity is what you need in 134 if you stay with it.

To go back to 12, you need to flush EVERYTHING to remove the oil, remove compressor and flush the PAG out of it using mineral oil, don't use solvent in compressor, put compressor back in place, put in the correct amount of mineral oil, evacuate and charge with R12. Also replace any switches or devices that you changed due to 134 pressure differences with appropriate parts for R12. Make sure you get ALL the flushing agent out of the system. This can be difficult in the evaporator and condensor, particularly the condensor.

Also, in hot weather, a 24 hour evacuation is not necessary. The hotter the components, the quicker the moisture will boil out under vaccum.

Best of luck,

I knew it
 

Thanks Larry for the kudos. And thanks also for answering Neils question so quickly. That why I love this board. There's always a friend not far away with the answers you need to the questions that you have.

Larry- why can't I just use the specs on the W124's R134a sticker? I did install a R134a condenser, and a R134a compressor, but still have the original R12 evaporator.

Thanks for the flushing tips if I go back to R12.

:-) neil
1988 360TE AMG
1993 500E

Hey Albert!

Congrats!! That cold air rushing in must seem twice as sweet...;)

I'm still unsure about tackling mine this summer - time is my enemy, but I have more confidence about it now. Thanks for all the advice.

Chris

Hi Neil,
 

I converted my car to r134 and it cools great when moving but, in stop and go traffic is not as cool. However, I don't remember too much of a difference with R12. As you know, the 124's A/C is not its greatest asset...
I just helped Neumann replace his evaporator, I think you already got in touch with him, but his newer system already has r134 from the factory. He has a 94 E320.
BTW, when are you moving to the area? Did everything work out for you?
See you!

ke6dcj,

Yes, since you've changed the components this would be close. Usually in a converted system you have to get close and then experiment with charge while CLOSELY watching high side pressure. It can get away from you so be careful when adding charge. Add a very little at a time then let system fully stabilize before deciding whether or not to add more. Watch vent temps closely as well.

Good luck,

Thanks Larry. What pressures on the HIGH and LOW side should I have with R134a when everything is stabilized?

Also, what should the vent temp be?

:-) neil
1988 360TE AMG
1993 500E

This is one of the problems with converting to 134, excessive high side pressure. On converted systems the high side pressure can sometimes go up to 300 PSI. The important thing is that you don't get into a situation where the pressure runs away. The high side pressure should stablize once the vent temp is stabilized. There are no hard and fast pressur or temp readings to look for. If you are getting a stable 40 degree vent temp and the high side does not continue to increase after stabilized, you are probably okay. Proceed cautiously when adding 134. This is another reason for staying with R12 in an R12 system.

Good luck,

A/C cold, but not blowing correctly
 

Larry,
The A/C is cold, but when I press the HIGH button, it doesn't blow strong like before. When I press the AUTO button, it too does not Blow strong like before and the LOW button barely blows at all.
I start the car and press HIGH and gradually over the next mile it begins to blow higher and higher till it hits a its new High speed which is considerably less that the original High speed was. HELP!!!

Albert,

The only comment that I know to offer is that, when I have seen the ACC go all over the place like this, I've seen the fan that draws sample air through the grill near the rear view mirror not working.

This small fan is in a few different locations on the various model 124's. Mine is near the glove box.

You could check it by holding a cigarette(yuk) or some other source of smoke near that little grill and see if it draws the smoke. If working properly, that fan draws air through the grill any time that the ignition switch is on.

Hope this helps and best of luck,

That's a fan?
 

There is a small black box located on my passenger side where glove box would be if I didn't have Air bag that commects to a tube that supplies air to the CAN box. You think maybe I didn't connect it back properly??

I'm ignorant of the later iterations of the 124. Are you saying that you think the temp sensor is in the control box you mention? If it does not draw smoke at the grill intake, this certainly sounds like something worth checking.

Good luck,

No, you were saying something about a fan. I said that I think there is a "fan" or some kind of black boxy looking apparatus that is connnected via a hose through the firewall to the CAN cox. The temp sensor is in the roof as you describe. I have removed the headliner and am familiar with the parts of the roof assy. I just went out and turned the ignition on(did not start the car). The lazy blower is evident even now. Maybe I didn't connect something or perhaps its the Blower Motor Relay. The motor even sort of oscillates(+- a few 10's RPM) under power.

(Edited Jan 05 - I don't remember what happened over time but the problem went away. So now things work as they were designed to)

My evaporator finally gave way at 18 years of service.

Also, we must have done the R134a conversion correctly (EVERYTHING NEW including dual fans) because she blows nice and cold in JAX, FL.

Any opinions on the ACM or Meistersatz evaporators ?

TIA,
:-) neil

It's been over year now with the ACM evaporator, and she still runs cold.

:-) neil