At Least the Evaporator is Apparantly not Leaking
 

Well, about a month ago, I noticed the air in my '88 300E to not be cooling very well. This worried me, afraid of the infamous evaporator problem. I had never had to add refrigerant, so I just hoped that it was a tiny leak that had lost the refrigerant over the period of many years.

I charged the system, probably added a little more than a pound. I drove the car and got vent temps below 40 degrees. I was VERY satisfied, and wishing for a sweater. I also put in UV dye at that time.

I had not driven the car until a few days ago and then drove it to find that the vent temp is only getting down to about 52, best case. I worried that I had a bad leak and got out the black light. I went over it THOROUGHLY and could find no leak anywhere. Today, I put the gauges on to see where I stood. I STILL had the same pressures I had when I charged it. It is making condensation drain like Niagra Falls so I am convinced that the refrigeration portin is working well.

This means that either a flap under the dash is not working properly or the climate control is calling for coolant. Possibly the heater valve could be seeping a little coolant through I suppose.

Well, anyway, I have been SOOOOooooo lucky with this car to have never had to do anything to the a/c. I am really glad that I have no bad leak.

Are any of you intimately familiar with the climate control et al? Can you suggest anything? The temp sensor blower is working. The blower motor is blowing well and all the vents are putting out cold air, it's just that the air is not as cold as it should be.

BTW. My pressures are: 28 low, 275 high, about 52 or 54 vent temp.

Thanks,

What was the ambient air temp Larry? If you are getting 45-50 degrees cooler than ambient, everything is working correct, as I understand the system.

Just shadetree refridgeration talking.

What is the sight glass showing ??

Ambient was about 90. I have kept a dial thermometer in the vent for the last few years. In the past the vent temp would be right at 40, even if it was 110 outside.

Sight glass is clear and pressures are on the money. The problem is not with any refrigeration component or charge level. The problem is with the climate control.

Since I posted last night I remembered that I now have a service CD. I gave a quick glance at the CD and it appears that the problem may very well be a temp sensor. It looks like there will be some serious troubleshooting here.

Since the blower is running and air is coming out where it should, it appears that there is no flap or vac problem. It looks like a sensor or heater valve.

Now that the work week is starting I probably won't be able to do anything more until the weekend. I will keep you posted.

The CD has the proper resistance values for the temp sensor so you can double check it. The problem may also lie in the sampler blower (aspirator motor), but I do not know where that is hidden on your 124. On the 560 that was the final item needed to get the AC work correctly. In my case the blower was working but not efficiently, changing it cured the problem.

My problem was that the AC would blow on high, freezing you out, then when it adjusted speed, the interior would heat up until the blower kicked up speed. Basically the reaction was seriously delayed.

Hi Larry

You may want to double check the vacuum elements for potential leaks, easily accomplished at the switchover valve assembly behind the glove box. (<20 minutes) As you test the elements for leaks try not to exceed 3.5-4.0 inHg during the test.

One other thought, when the A/C system is turned off are you able to feel air passing through the ventilation system while driving down the road? If so you might have a Fresh Air/Recirc element that is contributing to the reduced efficiency at the vents.


:cool:

Well, Mike may have been right with his first response. I read the "Checking Refrigerating Capacity" section and there is a chart that gives vent temp vs. Outside temp. The number I got yesterday matched ambient temp on the chart. It could be that the system is operating correctly.

What makes me suspicious is the fact that I have kept a dial thermometer in the vent for the last few years. In the past I remember the vent temp ALWAYS being right at 40F in any summer weather. Maybe my memory is wrong. I am entering my senior years after all.

I'm going to drive it at night with colder ambient and see if the vent temp tracks the chart.

Thanks for the replies. I have checked the sensor fan and it is working.

I will also try the system off/see if there is outside air check.

Have a great day,

I'm with you, Larry. I keep a thermometer in my vent and it is always at 42 degrees, except in stop-and-go traffic it will ease up to about 50 on a hot day.

Maybe my memory is not going away after all. According to my reading, if the vent temp goes much below 40 or 41, then something is not working correctly. I'm sure this is to prevent evaporator freeze up.

Too bad, now I can't just believe the chart and leave it alone. I will have to continue my troubleshooting.

Thanks,

Larry -

It's probably worthwhile to pull the glovebox and test the vacuum actuators with a mityvac. It's an easy task and will determine whether you have any flap problems.

I'll place a bet that you've lost one or both portions of the fresh/recirc flap. The difference between cooling recirculated inside air and Texas outside air can easily add several degrees to the vent temp.

- JimY

jcyuhn,

Before reading the MB climate control information, my thought would have been that I never hit the recirc button, so this should have no effect. Since perusing some of this material, however, it seems that the climate control automatically sets it in recirc mode under super hot cabin conditions.

I will pull the glove box and test these units.

Thanks for the comments and experience sharing.

Have a great day,

jcyuhn,

Intuition is correct very often. In this case I hope you're dead wrong. Correct me if I'm wrong, but according to the book, the dash will have to come off to replace the recirc pod.

Have a great day,

Larry, you may indeed have a recirc pod problem.

However, I almost never put mine on recirculate and it blows about 42' anyway. I've never noticed recirc making a significant temperature difference on a 124. So your temp problem, I would guess, lies elsewhere.

brewtoo,

Thanks for the response. In the past I have never pressed the Recirc button either. Yes, that was my thinking before perusing some of the MB service info. Somewhere in that reading I got the idea that the climate control unit will put the system in recirc mode if the cabin temp is high enough.

I hope my problem does NOT lie in the recirc pod. The thought of taking off the dash does not excite me. I should know tonight. I will pull the glovebox and check vacuum. If all vac is well, I am going to try to read the code pulses from the diag connector with an analog voltmeter. If that doesn't work, I'll rig up an LED.

Thanks again,

Larry -

Yes indeed, the dash does need to come off to replace the recirc pods - there are two of them. They are tucked on the far side of the heater box, hard against the firewall. You can just see the passenger side pod with the glovebox out. There's another situated likewise on the drivers' side.

The 124 actually runs the a/c in recirc mode most of the time. There are two recirculation levels available - 80% and 100%. Most of the time the car automatically selects the 80% mode. If it's hot enough out - Texas qualifies - it will choose 100%. About the only time the climate control will choose fresh air with air conditioning is in very mild weather - less than 75 degrees, perhaps.

Good luck, keep us informed.

- JimY

I have a zillion questions to ask regarding pulling the dash, but I will wait until I know for sure that I will have to pull it.

If I do pull it, will it be the 15 hour job to get to the pods? If so, I will have to decide whether or not to just do the evap while I'm there. Since the system is not leaking I really don't want to even touch a refrigerant containing component.

Wish me luck,

Larry, this may be of some help in diagnosing those pods.

The post came from this thread:
http://www.peachparts.com/shopforum/tech-help/42865-fresh-air-flap-actuator-pic.html


http://www.members.aol.com/hopinmystep/blurb.jpg

Good Luck!

Well folks, some slow violin music is definitely in order. Line numbers 1 and 2 from the 7 port manifold won't hold vacuum. It takes about 5 seconds to leak off about 3.5 in. Hg. Also line 7 leaks. It seems like I remember the defroster not working earlier in the year, so that is now explained.

In another thread I was reading about someone having put in 3 different evaporators. My system seems to be holding refrigerant well, so I don't think I will do the evaporator. I hope this decision does not turn out to be the kiss of death for the evaporator.

I have all the service information printed out from the CD. The only thing about the operation other than just the time it will take away from other things, is pulling the airbag. jcyuhn, did that bother you in any way? The instructions for "disarming" the airbag seem straight forward, but it still concerns me.

We have been fortunate so far with the Texas heat. It's about 85 today, but the triple digits may not be more than a few days away.

I have to give this some thought since I don't have to drive this car every day. It is merely a backup. My wifes 4Runner wouldn't start last week while I was out of town so she drove this car to work until I could get home. BTW I simply had to put a fuel filter in her Toyota. The a/c was just like it is now and she didn't complain about it. We're talking about a woman that absolutely cannot live without air conditioning.

It is cooling, but not real well. I expect that when the triple digits hit, it just won't cut it, especially for her.

There is always at least a LITTLE good news in everything. If I take it apart, I don't have to rush to get it back together. Also if I go down to these actuators, I will have a lot of experience and hopefully confidence behind me if I ever have to do the evaporator.

Thoughts and comments are appreciated.

BTW, jcyuhn. If I would have taken your bet maybe all would have to do now is fork over some money instead of tackling this beast.

Have a great day,

I just had a thought. The way these are connected together, if one leaks, then in effect, they both leak since they are connected together before being connected at the manifold.

Is the one behind the glovebox replacable without pulling the dash? If so and IF I were VERY LUCKY, that might be the only one that is leaking and replacing it would make it operational again. Keeping me from having to do this job in the heat. It's something I would much rather do in October than July or August in Texas.

Thanks for your responses,

Larry,

Have you considered as to whether or not the repair is essential? You are probably like me and cannot stand the thought of something not working as it should. In a situation like this though, I would be asking myself if I could live with the problem (if no damage will occur) until there was a greater need to pull the dash apart (eg. evaporator failure). If it simply means that the air-con will not be quite as cold as it should, then I think I could live with it for a while.

I realise that your 124s got the pushbutton full auto climate control whereas ours got what I refer to as the "manual" climate control with dual temperature thumbwheels and rotary controls for air direction and air volume/fan speed. I therefore don't know how much is common between the two systems. I have mentioned here previously how we don't seem to get as many problems with ours with the lack of the pushbutton unit and associated electronics and our 124 evaporators don't seem to have the same reputation as yours. One obvious difference is that ours have separate left and right heater cores and where you have a mono-valve we have a dual version (a duo-valve?).

I'm fairly sure with ours, air volume and direction are controlled directly by the person moving the controls, so we presumably do not have the vacuum actuators/pods associated with these functions. We do still have a recirculation pushbutton and therefore at least one vacuum pod (maybe the same two as yours) for this function. I don't know if we have several stages of fresh vs recirculated air as mentioned by Jim Y, but I do know that a few minutes after starting the air-con on a hot day with a high fan speed selected, there is an audible change in the air path (not air speed as remember our fan speed control is manual). This suggests to me a change over of fresh vs recirculated air and that there is still some degree of automation in our "manual" system. My understanding was that normally, fresh air was used unless the recirc button was lit (this function self cancels after a period of time to prevent build up of stale air/CO2).

I'm probably getting off the track here with all my waffle, but the point I'm getting around to is that, to the best of my knowledge, our system uses refrigerated fresh air most of the time and copes with our Aussie climate in summer just fine (often around 40 degrees C). That is even in our '90 300TE which has 134a retrofit and the greater internal volume of the wagon to cool (although being a wagon, it has the larger version of the Nippondenso compressor). In the six years we have owned it I have had refrigerant added once. If ours works in our climate with refrigerated fresh air and that is the "failed mode" of yours, can you live with it in your climate?

I once had to make a similar decision with my '73 350SLC. One of the air direction flaps on the driver's side jammed preventing me turning off the heat on that side. I was faced with the choice of pulling the dash apart to fix it properly or simply disconnecting the linkage to that flap from under the dash which could be accessed fairly easily. The latter option (which I chose) simply means that when the heater is switched on for either the driver's or passenger's side of the car, the driver's side gets heat. There is also less progressive control of the heat on the driver's side. At the time I figured I could live with that fault until I had to pull the dash apart for something major. As it turns out, that was about 18 years ago! Nothing major has necessitated removal of the whole dash yet.

Again I ask, can you live with it until something really requiring removal of the dash such as the evaporator occurs? Not that I would wish something like that on you.

Greg

Greg,

I appreciate and I enjoyed reading your response. Yes, of course, I am considering just leaving it. I don't think I will make that decision for another few weeks. In 2 to 3 weeks, maybe less, we will be dealing with high temperatures above 40 degrees C and low temps of about 32 degrees C.

I will drive it one of those brutal afternoons and see if it can keep up at all. I also must factor in the use of the car, which at this point is a backup, but I also use it for a long distance car since my primary is a very small, great handling but associated rough riding vehicle.

Occasionally I have to take a long, driving trip for business reasons. If one of those trips were to come up two weeks from now, I could always tape over 90% of the fresh air vent and make the trip.

All this sort of reasoning is a little too rational for me.:D As you correctly surmised, part of the motivation to tear apart the dash is that I want the car to be correct. Also, I am a terminal carnut. I don't do my own car work because I have to, I do it because of the satisfaction and pride that I feel from doing it myself. I know, that makes me pretty sick, a glutton for punishment I suppose. I rationalize this some by the fact that it seems that every time I get someone else to do car work I experience grief due to their incompetence.

In this particular case, I do have someone that I know could do this right, but is it worth it to shell out $800 or $1,000 to have it done?

I take pride in the mechanical condition of this car and how nice it is to drive. Cosmetically it doesn't look very good at all.

As for your manual climate control, there are many of us in the US who are very jealous. I have a European version 240D that I drove over a half million miles with good ol' manual climate control. It never gave any trouble that I couldn't fix in a few minutes and those times were very rare. I have posted before how much I would appreciate this car if it were manual everything right down to manual roll up windows. In the US I am very lucky to have manual transmission. Only about 300 of them made it to the US in '88 with a manual and I searched a long time to find it.

I still hope that someone will let me know if I can replace the right side pod from the glove box access. If I can, then I might be able to get it fixed with very little trouble if I'm really lucky.

Thanks Greg and everyone. Please keep the comments and violin music coming.

Have a great day,

Good morning all -

I did not pull the airbag or steering wheel when removing the dash. All the U.S. cars have the telescoping steering wheel; I just ran it all the way out. This makes sufficient room to pull the instrument cluster and remove the dash.

I think it took about three hours to pull the dash and center console. I don't think Larry is looking at more than 5-6 hours total work here. It's much simpler to replace the vacuum elements only as opposed to the evaporator. Dave (gsxr) should be able to give a good estimate of the work time, I know he's performed several pod-ectomies on 124 cars.

I don't know for certain on the 124 cars, but on other chassis the internals/mechanicals of the hvac system were identical worldwide; only the "front end" controls differed between the automated U.S. and manual systems used elsewhere. They all used the same vacuum elements, it was just a matter whether those elements were controlled by an automatic brain box or directly by manual switches.

- JimY

Hi Larry

Should you decide to go in and conquer the beast there is a plastic bell-crank that is associated with the operation of the Fresh/Recirc system which does break at times.

Just and FYI in the event you need to locate it: the bell-crank is located in the 201 HVAC parts system, I was unable to find it listed with any 124 information. ;)

Good Luck

Well, I just called Phil and ordered the pods. I just can't make myself tape up the fresh air intake. I can't stand to have my stuff patched up with baling wire or tape.

I am tempted to start tearing it apart this weekend, but I would probably be better served to wait 'til the parts arrive.

I also ordered a new cap for my windshield washer reservoir. I wonder which will be the easiest job, replacing the washer reservoir cap or the pods?:confused: :D

Thanks for all your comments and please keep any suggestions or words of wisdom coming. I hope this does not just turn out to be a practice session for evaporator replacement.

I would rather do an entire engine rebuild than to do ANYTHING under the dash. At least it appears that I won't have to spend much time standing on my head for this one.

My brother in law, who is an dealership MB tech, insists that pulling the steering wheel is so easy to do that there is no need to leave it on. He insists that as long as the ignition is off there is no way that the air bag can blow.

I'm tempted to put it on the lift about three or four feet in the air. That way I can stand or lean over to get under the dash and climb into the car for the work over the dash.

Wish me luck,

I feel the same way.

Over the past few months I removed/replaced the dash in the '81 300D. It was alot less trouble than I had anticipated.

The Brown Truck left the set of vacuum pods today. I built the LED Pulse Counter tester and figured out how to check the Climate Control Unit for trouble codes. There are none set.

I wanted to do this before I started tearing everything apart in case there were a temperature sensor or something in there that might also need replacement. I don't want to do this more than once.

So, unless something else comes up, I'm going to aim every fan I can find at the front passenger compartment and start the project. We had our first 100 degree day today, so I'm sure this will be a sweaty project.

Wish me luck,

At the last minute (Thursday) I remembered that I had strongly suspected a leaking heater core sometime back and ran some bars leaks through the heater core. It has not leaked or smelled of antifreeze inside since. Because I have to pull the heater core to get to the floor flap pods, I ordered a heater core from Phil and got it Friday.

On Friday morning my boss called and said that we are having a meeting at his lake house in Missourri beginning on Tuesday. He said to bring swim trunks and golf clubs, so I guess he's just getting us together there so he can write off the lake house.

Anyway, it will be about 450 miles one way, so I decided not to tear apart the car this weekend. I planned on taping off the fresh air vent for the trip. I covered about 80% of the vent with metal film tape and gave it a test drive. It made little if any difference. I then taped it off entirely except for the little center screen. I think that the center screen is for the water drain only. I still saw no difference. I pulled the tape and ran another 10 miles or so and still no difference.

With a 96 degree outside temp, I was making about 46 to 48 degrees vent temp. That exceeds the performance test parameters in the MB manual.

Since I don't know and can't visualize the positions of the recirc doors, I don't know if taping the fresh air vent at the cowl is having the effect that I thought. After pulling the tape I ran it at speed with the climate control off and still got air through the vents. I should have tried that with it still taped to see if there was air through the vents.

Even with it 96 degrees I was quite comfortable, but this was all driving at speed on country roads. I think if I had to drive stoplight to stoplight it might not keep up.

So, I expect to do the podectomy next weekend assuming that our "meeting" is over.

Your experience and theories are still welcome and solicited.

Have a great day,

Larry,
As a brief aside & followup to something you just said, do you know the route of the water drain below & in the middle of the cowl screen? For example, do they connect to the a/c drains or act as a separate drain? Where does the water exit the car? Thanks.

No, I don't know the water drain route, but maybe I will after this ordeal is behind me.

I drove the car 900 miles or so in the last three days. Unless I am in stop and go traffic in 95 degree ambient, it cools pretty darn well even with that hot fresh air.

Have a great day,

Larry,

If/when you start, I highly recommend taking digital pictures of EVERY fastener that might look like it could go back together a different way. Especially if a removable clip is involved, I found the pictures I took to be invaluable in figuring out what went where, and in what orientation.

I don't believe the pass. side recirc pod is removable with the dash in. There is a pod on the R side of the heater box that is for defrost and is doable, but I suspect it is a "hard" doable.

With the proper pages from the manual, the dash R&R isn't too hard, just very very very time consuming. It took me 18 hours over three days to do mine (for the first time), but I wasn't in a hurry.

Good evening Larry,


Yea, I'm with you on a/c performance right now. I decided the 86' would get all new actuators just because of the age.

I haven't had any heater core problems(?). Just noticed a faint wetness on one of the orginal hoses.

Just a thought- I've run into several cars- GM, Ford and Mercedes which have behaved this way. All of those cars had dirty evaporator cores. For the W123, I was used a comercial "no-rinse" product. For the quick and dirty jobs .. I drilled an access hole and plugged.
I know they make the no-rinse with a flexible hose extension. I'll probably do it when I've got apart. I think the automotive stuff runs $10-15 a can. Talking with shop guys.. they only seem to acknowledge mild killing stuff. All the comercial HVAC guys are familiar with these products and use them.


Michael

I don't doubt that the evap could use cleaning, but I don't think that is my problem because the refrigeration portion performs so well. It performs beyond the performance specs in the manual.

If it were recirculating as it should I could make ice cubes.

I am glad you brought this up though. If I can get to the evaporator to clean it while I'm in there I will do so.

Have a great day,

I'm sure you will have access when you are in there...


It will make the air seem much fresher- even if you don't think you need it!
Reduced airflow is ussually the key element I see. Check the pressures and vacuum elements... then I investigate cleaning.

Michael

Well, as it turns out I have to drive to Kansas next week, so I am going to postpone this job once more. I hate to try to do it in one very hot weekend.

When I get back, I shouldn't have to travel again until Aug 23, so I should have enough time to tear it apart and no be so hard pressed to get it back together.

Have a great day,

I got the car positioned on the lift so that the front doors would open. I positioned a squirrel cage fan to blow through from one side to the other.

I raised it up far enough to disconnect the speedo cable and drain the coolant, then let it back down to a level where the bumper is slightly above waste high. This height really works well for getting under the dash and still it is easy to climb in and out of the car.

I got the instrument panel off and all has gone pretty well so far. The only bad thing that happened was that I broke the rocker switch carrier where it snaps into catches on either side of the upper most portion of the console. I might be able to JB Weld the piece back onto the carrier.

I have about four hours in the job so far, but part of that was hauling the fan and getting it in place, getting the car positioned just right on the lift and so forth.

It looks like I have a lot of work left to do. I estimate about 3 to 4 hours to get all the pods replaced and to replace the heater core. Then I expect it will be every bit of 4 hours after that to get the dash back on and fill the cooling system, etc.

I hate working under the dash and I'm not near through yet, but so far it's not as bad as I thought that it would be.

Have a great day,

Larry:

Having just finished the job myself (plus evaporator), here's some tips!

You do not have to pull the AC box to replace the servos, but it will be a PITA (less than pumping down a leak-free AC system, though!).

You will need an 8mm nut driver and 8mm ratchet, and a 10mm wrench, plus a 24mm to remove the headlight switch nut. Small and large phillips.

You must, alas, remove the console to replace the floor flap servo, but if you don't need that one, you can leave it in.

You need a flexible blade putty knife to get the trim strips off the speaker covers, preferably blunt so you don's scratch anything or cut yourself like I did.

Removing the trim on the A pillar is a huge pain, my clips didn't come (they are still in there) and the guys who replaced the windshield a couple years ago glued them to the glass, so I suspect the are ruined anyway. You have to persuade the clip of out of the A pillar from behind -- DO NOT USE A SCREWDRIVER unless you want to replace the windshield if you slip.....

All but one of the servos is held on by little twist lock feet and a locking tab. The center vent on on top has three posts and pushon clips -- get new clips, I shot two of them across the room since I had to break the pins off to get the sero off.

Otherwise, fairly easy, if very fiddlesome.

If the servo inside the box (diverter flap) is bad, you must remove the AC box on pre 1990 models. later models let you reach through the top.

For just servo replacement, you don't have to remove the cross member under the dash.

Going back in, I found it much easier to remove the center vent than to get the hoses connected with it in place -- one screw on the right side, two spring clips on the left. A small Torx screwdriver fits nicely into the hole on the spring clip so you can pull it inward to release the clip.

More notes available if you need them.

Peter

Hey larry,

I've got my box of vacuum actuators right here! Maybe I should drive up at leave the car with you for a week...

Much more industrious! But, hey I've got a new member of the family occupying my time since 7/17. Got to say- he's a cute.


Michael

Arrh?

"If the servo inside the box (diverter flap) is bad, you must remove the AC box on pre 1990 models. later models let you reach through the top."

Are you absolutely sure? I was going to go with the post 94 airbox assy, but was assured that I could replace the diverter servo without removing the box.


Michael

psfred,

I appreciate all the tips, but I already have the instrument panel off.

I am also replacing the heater core, so the top cover must come off. There are two phillips screws in the front of that cover that are near impossible to get at. I can't get a stubby, a short phillips, a regular phillips or an offset on either one of them. The metal that protrudes rearward from the base of the windshield is in the way bigtime. When I was in the military, we had a phillips screwdriver with a long flexible shaft like a speedometer cable. We used it to get in some tight places on a missile control system. If I can find such a tool, I can get to them. I am stalled until I get these screws out. Any ideas?

samiam4,

When I started reading your post my first reaction was that if you show up wanting me to do a podectomy I will meet you at the door with a shotgun.:D Then when I read about the new addition to the family my heart softened some, I would leave out the shotgun and only politely tell you to go away.:D

This job is a real pain and there are many clips and stuff to break. The person that I WOULD meet at the door with a shotgun would be the engineer responsible for making this thing such a PITA to work under the dash.

Have a great day,

.... Sorry to hear the pain. I'll get to mine next week.


I'm just in a concern about having the right parts and all the right parts... eeek! This thing about having to pull the airbox on the 86' is worrysome to say the least. If I've got the dash out and have to pull the evaporator- I'm going to be replacing a few more a/c components.

Way too hot lately without good a/c.

Michael

Larry:

Check all your right angle rubber connectors, too -- all of mine at the switchover valve were bad (some had already been replaced). AC works great, but I broke that switch rack, too. What happened to a couple screws or a spring clip rather than prying away at the plastic?

It's much easier to replace the vacuum elements with the AC box out.... but I'd rather mess about with the box in.

Those two screws are rather difficult with the box out, too. I used a small phillips at an angle, but I expect you are up against the windshield, too, right?

If you are using a small, inexpensive "phillips", check the point. If it's pointed rather than flat on the end, grind a bit off and it will fit better. A stubbie is too short, a standard that actually fits is probably too long.



Michael:

Yup, you have to take the case apart, no way to get your hand in through the diverter flap. Changed later, exact date I'd have to look up.

Change the lamps in the headlight, ashtray, vents, and climate control while you have the whole thing apart, you have to take most of them out anyway!

I'm not quite done yet -- have to get new right angle connectors and new push rivets for the glove box (they nearly all stuck coming out and I ruined them) and I dropped one of the climate control mount screws and so have to fish it out from under the front seat to wrap up.

Also have to get the gunk out of the ash tray pivots so it doesn't groan when it's opened and find some screws to mount it with -- they were missing (someone has been in here before me!).

Peter

Psfred,

I though you were to pop the diverter flap out of it's place carefully. I think Easley had a write up.


Michael

you can if you want, but you will have to have smaller hands than mine to reach in, it's too small as I remember, and no, I'm not gonna take it back out to check!

Manual is pretty specific, prior to 1990 sometime, you take the box apart, after than date you just take the top cover off.

you can check the servo from the switchover valve easy enough.

Peter

Hey Larry,

Show us some pictures!

The servo is good, I checked them all before tearing it apart and only the fresh air and defroster leaked. I will replace them all while I'm there.

I need the two screws out so I can replace the heater core. According to factory service info and what I see taking out those two forward screws will indeed provide access to the servo AND the heater core.

I am going for a flexible phillips screwdriver at lunch and I found something called a "Skewdriver" in the ToolSource catalog. I am pretty determined to get these two screws out. I do NOT want to disturb the non leaking evaporator just to change the heater core. If I have to I will leave the heater core and that servo in place before I will TOUCH the evaporator.

As far as pictures, I think it's all too ugly to show pictures. I will see what I can do.

Thanks for the replies,

Larry,
I know its the last thing on your mind, but at your convenience if you could explain how & where the a/c condensation water drains out of the car I'd appreciate it.

Been there, done that, took pictures........Laryy, I used s short Phillips screwdriver and didn't have any problems. You just have to have good dexterity and a mirror.
http://www.peachparts.com/shopforum/tech-help/33725-floor-vents-not-functioning-opening-hvac-86-300e-w124.html

Cap'n,

Well I got those screws, replaced both pods, the one on top of the cover and the one that you have to pull the heater core to replace. It is inside the box, in front of the heater core. I think it is for the center vents.

I tried every phillips screwdriver I own and on my car the metal that sticks rearward from the base of the windshield is in the way. I could not manage a stubby from behind. I got a screwdriver with a wobble joint on the end and loosened some things to move the box rearward ever so slightly and that did the trick.

Now my worries turn toward getting the new heater core in and sealed. The last thing I want is a leak. There are plenty of things that can go wrong and require taking it apart again, but that is one of my worst worries.

So, if I can get the heater core back in and sealed and the front fresh air pods replaced, then I can start going back together with it.

I'm afraid if I were doing this one in a shop being paid flat rate, I would be looking at a thin paycheck for the week.

If I were only replacing the pods that were bad, I would probably almost be done though, the heater core part has really added a lot of time.

I will look for the condensation drain, but I think it is sort of an accordian looking tube on the right side of the HVAC box. There might be another on the other side.

I only worked about 2.5 hours this evening. After a day of stressful work, that's about all the energy I have left before coming in and winding down for the evening. If all goes well, I should be done this weekend, maybe sooner if I were to really get lucky. I'm not in a hurry. I just want to get everything back together correctly so I don't have to take anything back apart.

Have a great day,

BTW, I wonder what sealant if any I should use on the heater pipe o-rings? I expect that they are put in place dry. There is a small amount of what looks like plumbers putty that is in the hardware package that came with the heater core.

Thanks,

Larry,

There are two condensate drains on the HVAC box; one each on the driver and passenger side. They come straight down out the bottom of the box and go down through the transmission tunnel. I think the drains are pretty much in the rearmost corners of the box.

As condensate drains Daimler uses insulated foam tubes with an internal spring to hold the shape. They probably didn't leak, but if you so much as touch them they turn into dust. Are you familiar with the disintegrating foam piece on the 123 air sampler tube? I think it's the same supplier :)

I replaced mine while the HVAC box was out. Just purchased $1 worth of rubber hose at Lowes. I *think* 3/4 inch (about 5/8 ID) was the correct size. It's a good press fit onto the flanges of the box; I added some zip ties for a bit more security.

Given that you've rocked the HVAC box out of position to reach those infamous screws, I think you should inspect the drains. It's quite possible they've torn or dislodged.

I've got a picture of the drain locations with the box out of my 124; I'll go dig around the basement of my computer to see if I can find it.

- JimY