ksing44

I am still a little afraid that I may have the dreaded and expensive air conditioning failure noted for these cars. Last year, in June, the air conditioning was recharged and filled with the fluorescent indicator dye. Then in the fall I thought the system was fading, but with the cooler weather coming I just thought I wouldn’t worry about it until the spring. Sure enough, it isn’t very cold this year. I thought it needed to be recharged a second time, so I was sure I was going to have to rip out the entire dash and pay the whopping $2500 bill for the fix. I was willing to pay, but I was concerned about getting the dash reinstalled. Then last week I took the car to the very good independent mechanic that did the recharging of the system and he told me that the pressure of the system was fine. He told me that he thought the refrigerant had not leaked out. He also tested the temperature from the vents and he told me the temperature seemed OK. It was a rather cold day, however, and the outside temperature was virtually the same as properly cooled air. On a hot day, the air conditioning does not get anywhere near as cold as it did before. Since the independent mechanic couldn’t identify the problem, I made an appointment with the dealer for the 19th of June and I am hoping they can solve the problem. Since the pressure is good, I am hoping it isn’t leaking from the evaporator located under the dash. Could it be that the independent mechanics messed up a bit and charged the system improperly? Could the pressure be OK and not have the proper amount of refrigerant? I read about being sure to dry the system before recharging and being sure to fill the system with the appropriate amount of refrigerant. I am hoping it is simple, but I am willing to pay what ever it takes to keep the car like new. I just hope the dealer can figure out the problem. If you guys have any tips about the possible problems, I would be grateful to hear about them.

ksing44

I returned the car soon after the original recharging of the system so that the mechanic could search for a leak, but he never found it with his UV light. Then the dealer told me that sometimes it takes multiple loads of dye for the indicator to be visible in such places as the moisture drainage holes coming from the evaporator. I figured I would have to go back a few times to recharge the system to find the problem, but now the mechanic is telling me that there was no loss of pressure and I am confused about the original loss of pressure and the lack of sufficient cooling. T he air conditioning system must have leaked the first time, but that occurred over an 8-year period of time, so I guess it is possible that a loss of pressure isn’t really unusual for an "older car". I was kind of hoping that maybe a very slow loss of charge over 8 years didn’t necessarily mean that there was an obvious leak that would need immediate repair. If I had to get a recharge every 5 years, or even every season, it wouldn’t be so bad. Now however, it didn’t leak, but it isn’t cold.

The mechanic measured the vent temperature at 40 degrees, which he said was normal. However, as I said in the original post, it was a cold day so it didn’t take a lot of cooling to reach 40 degrees. The system does seem to cycle properly. I can feel and hear the system kick in on a more or less regular basis. It may come on a little more frequently or stay on when it is warm outside, since it never gets cold enough to relax the system, but on a cool day it operates like I remember.

Merceders

Hey Ksing44,

I had a similar situation with my 90' 230E (Right-hand-drive) and total understng for fear $$$$.

One hot day, the AC just blow warm air, and I believed the AC just need a recharge.

My mechanic recharged the R12 and used a sniffer to check for leakage.
they found the lead from under dish, so it is either the valve or the evaporator coil. They took off the whole dish and verify it the evaporator, not the cheaper valve.

but lucky I am in the other half of the world (Hong Kong) where car-fixing are charge by job, not man-hour. and aftermarket parts and experience MB mechinic are aboundantly cheap for W124.
I got my evaporator coil (new-aftermarket) and valve (new-aftermarker) replaced for US$400 (includes labour)!!!
(R134 is a bit more, maybe US$500 for all parts and labor)
Man there is a hell lot of job for taking off the dish!!

Now the AC is ICEY COLD as new !! even at 30C ( 90F)
Moreover, the dish is now re-tighten and those little squzzee are gone!
and I am one cool w124 owner


However, I would not have done it if its a US$2,000 job!

So, I suggest you to check and double check the AC Relay, Compressor Clutch, recriver-dryer bottle, and any other related components before opening your job order.

Good Luck,

Ed

ksing44

My 1995 E320 does use the newer, but not as good at cooling, R134 coolant. It worked fine until last year and I just haven’t been able to get it back to the way it was before the system was recharged. I am hoping the dealer can figure it out and that it may be a s simple as the independent mechanic just made some kind of mistake. I was hoping you guys would have a brilliant , but simple, recommendation to get my system back to cooool.

The temperature of the air coming from the vents is a little cool on a warm day, but the car never really gets cool inside. I noticed that the air is cooler if the fan is kept on low. As the fan speed increases, however, the temperature increases. It just seems that the cooling capacity of the system has been significantly diminished and that it can not keep pace with higher outside temperatures. This seems consistent with the coolant leaking out, but my mechanic told me the pressure is good.

I was thinking that the system could have less than the required amount of R134, even if the pressure was good. I read something about having the system vacuum-dried and wondered what the symptoms would be, if moisture were allowed to remain in the system.

bamberger_1

Hi,
I can understand your problem since summer is their the f..... A/C wont work. There is one more lead to check. Is the fan for the condensor working? It is the fan (or the fans, depending on the system) right in front of the condensor. To check this fan you need to bridge the pressure switch (red) which sits right on the dryer bottle underneath the ABS. Ignition ON and A/C on engine OFF bridge the switch shall start the fan. Refrigerant loss over 4-5 years is not a problem. R134 is just evaporating through the hoses and fittings. If the pressure is right it shall work. But normally when the system is refilled the system will be drained (evacuated) first. Then the amount of refrigerant is measured. If the suspicion is there of leaks Nitrogen will be applied to the system and the pressure drop is checked over time. If this all seems fine they refill the system, and maybe also changed the dryer bottle ($80 item). Ans than it is back to COOL. I had my '90 260E with the same problem, low refrigerant and no COOL. I even had to convert from R12 to R134. Now I'm a cool happy driver in the summer again.
My proposal let only the MB guys play with their A/C they know the systems better than anyone else. Even if they charge a little extra but you dont need to go there more than once, and if so it's under warranty.

mjtray

Sorry to jump on the back of the original thread, but I was wondering if anybody has any idea's about the following problem I have with my air-con.

I have a 1993 E280 with only 82,000miles. The aircon temperature is fine. The problem I am having is that when I have the AC working and I'm sitting in traffic, ever so often when the aircon kicks in, the idle on the car stumbles and it feels as if the car is lurching forward slightly against the brakes. Once I am clear of traffic the car behaves better but never as good as when I am using the car with AC switched off

If I switch the AC button off, ie press the EC button so that the AC does not work, the car idles perfectly in traffic and when you put your foot down, the car picks up real nice with no fluffing or hesitation.

Its only a little problem, but it would be nice to know why this is happening

Many thanks

Kestas

Mjtray, your problem may be as simple as a dirty throttle body bore that needs to be cleaned out. The deposits that accumulate choke off the airflow at idle. Idling in gear with the a/c on places the highest demand on idle air inlet.

mjtray

Kestas,

Thanks for your thoughts............is it a difficult job to clean the throttle bodies and is there any particular care I should take in doing this job, and secondly, do I have to use a specific cleaning fluid to undertake the job?

Many thanks

Kestas

I'm not familiar with your setup under the hood. With some cars it's quite easy. Just use a toothbrush and solvent. Mineral spirits should work. Carb cleaner is more aggressive. They even sell throttle body cleaner for those units that have a stick-resist coating. If possible I prefer to remove the throttle body to do the cleaning. That way you can hold it up to the light and know it's clean when you see an even ring of light around the butterfly valve. Don't forget to clean the edge of the butterfly valve in addition to the bore.

mjtray

Kestas........thanks for your guidance.......I'll give it a go over the weekend.

rp718

Thanks Kestas.

My 96 E320 has been doing the lurch thing off and on for about the past 3 months. I was hoping it wasn't something associated with the electronics. I'll take it apart this weekend, and hopefully the annoyance will be gone.

tkd_M119

but lucky I am in the other half of the world (Hong Kong) where car-fixing are charge by job, not man-hour. and aftermarket parts and experience MB mechinic are aboundantly cheap for W124.
I got my evaporator coil (new-aftermarket) and valve (new-aftermarker) replaced for US$400 (includes labour)!!!
(R134 is a bit more, maybe US$500 for all parts and labor)
Man there is a hell lot of job for taking off the dish!!


Maybe we need to do a "Group Ship" to Hong Kong for our AC evaporator fixes! I'm half way not kidding! Just think what we could do with a volume discount!

Tamara

Hello Ksing,
I would urge you to Do Exactly What Bamberger Suggests, if you don't believe us ....you can check out my horrible saga under the thread-poor compression equals bad a/c- and you'll get an idea what can happen. I wish you the best of luck,
Tamara