Brian McL

Hi...I would greatly appreciate anyones input on the "known" problem areas in the 124's A/C system for 1994 E320. I have a leak inside the car and I'm hoping it isn't the evaporator. I re-charged the system with a scented hydro-carbon (134 substitute )and the inside of the car has a very strong odour after sitting over nite. The charge is gone in 3 days....so it's a big leak. I'm pretty sure the leak is inside?
Can anyone start me off in the right direction. :(

Kestas

You need to narrow down the leak source. I like to look for leaks by flowing a soapy water solution over suspected areas. Any leaks show up as bubbles.

The best way to confirm evaporator leaks in a working a/c system is to inject a UV dye into the system, then check for leaks with a UV light. Evaporator leaks will show up as UV dye in the water condensate.

Brian McL

Thanks....good idea. But what next???? First the head gasket, then the wiring harness and now this....never had this much trouble with the 1990 300E.

Kestas

Let's see...... creaky door check straps..... headrest mechanism..... radiator neck...... flex discs.....

bamberger_1

unfortunately there is not much else inside the car of A/C components than the evaporator. It's not a cheap adventure since the whole dash has to come out first.

sshores

I had multiple problems with small leaks, (recharge 1LB ever 2 months). The ONLY way to find a small leak is to use a freon sniffer. I think the evaporator coil is a prime candidate if you can't see the UV dye. The estiamte for my repair from the dealer was 2 weeks (80 hours @$80/hr) labor and the part itself for a grand total of $2750.00.

Take it to a shop or a dealer with a sniffer. Hope you get better news than I did.

sshores

FYI, I have a friend who services MB's. He told me that he has used a 134A system sealer on small leaks.

It takes about 3 hours to set up and you need a vaccuum pump to evacuate the system. He told me that he did this on his Benz and it held a couple of years.

The thing that I am not sure of is how large the leak can be and have this leak sealer work. The kit costs around $45.00. He uses Adsit or IMPCO for most of his parts.

Hope this helps.

Brian McL

HI and thanks for the responses....well, it IS the evaporator. I took the whole dash appart to get it out. I mean EVERYTHING. Thought I would just remove "this panel here and see if I can get the sniffer in there, hummm, nope......well, maybe I'll just remove the airbags, see what I can see" 4 hours later I had the whole thing out on the floor. The evaporator sits in a mixture of sludge and yuk....the drains are clear but there is always a caustic mix of "stuff" there that eventually eats it's way through, and presto!!! a leak. Now I need to find a good after market replacement...any ideas?
Thanks
It maybe a good idea to revese flush yours through the drain holes......I sure will.
Brian

sshores

Lots of links to MB repairs here, try this URL.
http://my.net-link.net/~rgginger/mercedes.htm

This link shows evaporator coils at half the price I have been quoted. I've gotten brakes and rotors there, no problems with them.
http://catalog.thepartsbin.com/?year...mageField.y=15

Sorry, but you did get to the problem really quickly.

bamberger_1

how can this be done w/o flooding the car. Just using a garden hose???

bamberger_1

how can this be done w/o flooding the car. Just using a garden hose???

bamberger_1

how can this be done w/o flooding the car. Just using a garden hose???

Kestas

Did you find the leak point? I'm curious what the common failure mechanism is for these evaporators. Some say it's the thermal cycling of dissimilar metals. I wonder if it's the acidic action of decomposing leaves and other organic matter eating through the metal.

Brian McL

The leak was in fact in the middle of the evaporator and not at the bottom, as we expected once it was removed and we saw the condition of the tray it sat in. The fins at the bottom had started to dissolve....but the the leak was no where near the bottom. The metal in the area of the leak is all aluminium, fins and tubes...so go figure. There doesn't seem to be any logical reason for it. Maybe MB ordered this part to "biodegrade" like the wiring harness on the 104 engine. Problem is.... it starts braking down long before your ready to recycle the car.

Brian McL

The inside of the plastic case that the evaporator sites in has a plastic "dam" around the bottom. It's about 1 1/2" high, so it will take a far bit of water before it over flows. Don't forget, this area is meant to hold and shed water. Now, when you "flush" it put the water on very low, not full pressure from your tap 'cause then it will flood. Just a nice light flow. Run it for a couple of seconds and let it drain out. I would think repeating it 2 /3 times wouls be enough to flush out the nasty stuff. It should be something to do twice a year.

Kestas

Designed to hold water!!!!!.... Who's the idiot that came up with that brainchild!!!!!!!! Now I'm worried about my system. I thought my car was immune because people reported that it's not a problem with the 95 W124's. Can somebody confirm or deny this?

Brian, when flushing the evaporator box, where would you introduce the water? I think it may be a good idea to do this task every so often as preventive maintenance..... especially if people park under trees. (Oak leaves are the most acidic.)

Brian McL

Now that I've got the the whole system out, the only place that I can see to get water into flush is up through the drain. Unless you want to put an "inspection" port (drill a hole) on the top side, inside from the passenger foot wheel. Requires removing the carpet. Actually, that may be what I do. The chiller is to the rear and is not visible. The front one that you maybe can see through a vent is the heater core. The chiller is right up in behind. Almost under the windshield. Good luck.