98 E300 air condition - PeachParts Mercedes-Benz Forum

smacmoyle · #1 04-21-2009, 10:20 AM

Its that time of year again and my E300 just sucked up 2 cans of R-134. Is the compressor the usual suspect here ? Anyone have any suggestions on repair or replacement of the compressor or clutch and how hard is it to pull ? Its cold now but for how long, I dont know.

KarTek · #2 04-21-2009, 12:37 PM

The evaporator is the usual suspect on these models. Can you smell the funky freon smell in the mornings when you get in the car? The replacement is apparently a huge PITA...

TMAllison · #3 04-21-2009, 12:56 PM

From memory, it only holds 2.2 lbs. Without evcauating and refilling how do you know it isn't horribly overfilled?

Have you pulled actual values and checked error codes?

smacmoyle · #4 04-21-2009, 01:09 PM

Yeah, now that you mention it. It does have a funny smell. Its not giving any codes. I should check if there are any stored.The compressor clutch was still engaging. It was just blowing warm air. I have a cheapo gauge that only goes on the low side. I did not evacuate it. It stayed around 40 psi and got cold. I imagine that when the system goes below a certain psi the clutch will stop engaging. I would guess an evaporator may be repairable and maybe leak checkable on the car with some soapy water. if the leak is small enough and the system lasts through the summer laziness may win. Thanks guys.

TMAllison · #5 04-21-2009, 03:37 PM

The AC actual values and error codes are read via the CCU display. Not related to the CEL.

nhdoc · #6 04-21-2009, 04:03 PM

Mine has had a slow leak since I have owned it. Since it leaks at the rate of a can or two a year I have just lived with it and added when necessary. This year got a little bit of ambition and I used some professional stop leak stuff which required that I evac the system and refill from scratch called Super Seal Premium Pro™ A/C System Leak Repair Kit. I did that about a month ago and it is too early to tell if it had any effect or not but so far it works fine so no harm done at least. FYI, this is the stuff I used:
http://www.cliplight.com/automotive/products.php?pageID=Product_Details&productID=16

KarTek · #7 04-21-2009, 04:26 PM

Marty, did you extract any oil from the system when evacuating? Did you use a recovery machine or just a vacuum pump?

nhdoc · #8 04-21-2009, 07:14 PM

Quote:

Originally Posted by KarTek

Marty, did you extract any oil from the system when evacuating? Did you use a recovery machine or just a vacuum pump?

My system was almost empty already when I checked it so there was no need to recover anything...that's why I elected to use the stuff, because I felt my leak might have gotten a little worse. I'd say there was a few ounces left in my system when I started (at most), so I vented it slowly and then hooked up my vacuum pump to draw it down to vacuum before refilling it. It holds a good vacuum so the leak wasn't too big, just big enough to leak out a can or two during the summer.

pmari · #9 04-21-2009, 10:55 PM

http://www.eclassbenz.com/node/27
Instructions
Part 1 — Collect Sensor Data
First we’ll get the values of all the various climate control sensors. These sensors constantly monitor data like air temperature, refrigerant pressure, etc. Odds are if something’s wrong, a sensor will pick it up. Let’s get started!

Start your car.
Press the “AUTO” button on your climate control.
Turn on the A/C (i.e. “EC” light must be off; if the light won’t shut off, continue with this test. We’ll address your “EC” light on the next page.)
Let the car idle for about 3 minutes.
Set the temperature on each side to 72°F. You can do this quickly by pressing both the red and blue arrows simultaneously.
Press and hold the “REST” button for five seconds or until the left side of the display says “01.” The left side indicates which sensor you’re checking. In this case, #1 is the in-car temperature sensor. The right side of the display shows the value of sensor #1 (in this case, the actual in-car temperature).
Press the “AUTO” button on the left side to move to the next sensor. Press the “AUTO” button on the right side to move to the previous sensor.
Record the ID number of each sensor (left side of display) and its corresponding value (right side of display). For example, in the picture on the right, you would record that sensor #5 has a value of 6.
You only need to do this for sensors #1-8. You can write down the values for the other sensors, but they’re not really related to air conditioning function.
When you are done, press the “REST” button again to exit the self-check mode.
Part 2 — Collect Trouble Codes
Now that we have all the sensor values, let’s check the computer for malfunction codes. Read this carefully, because you have a 20 second window after switching on the ignition to load the trouble code display mode.

Ignition must be switched on. 20 second timer starts.
Increase the left side temperature (left red arrow) until left side says “HI.”
Decrease the right side temperature (right cold arrow) until right side says “LO.”
If your 20 seconds passed, switch off the ignition and switch it back on. Your HI/LO settings will be preset. Timer restarts.
Press and hold the “EC” and “REST” buttons simultaneously for at least five seconds.
The screen will go blank.
Load the first code by pressing the right side “AUTO” button.
If you have any error codes in memory, the screen should look like the figure on the right. The ‘E’ stands for “error.” In this case, we have error code B1234.
Write down each error code. To cycle through the codes, press the right side “AUTO” button.
When you finish, press the “REST” button to exit.

Matt L · #10 04-22-2009, 10:09 AM

There is little reason to extract codes and read sensor values if you know you have a leak. The codes will show that you're low on refrigerant. Well, yea. That's the problem.

From what I've heard, the condenser is the most likely thing to leak on the W210. We do not yet know whether the evaporators will be a problem on this model; they aren't old enough to show up yet. And yes, the evaporator R&R is still a huge job.

Guessing at the leak location will get you nowhere. Look for oil, add dye and run the system, or use a sniffer. Or all three.

Note that once the compressor starts, low refrigerant will not shut it off unless the loss is very severe. The low-pressure cutout switch (pressure sensor, actually) is in the high-side line. The pressure goes up when the compressor runs, and the low-side pressure is not used for cycling (or monitored in any way).

KarTek · #11 04-22-2009, 10:11 AM

It's my understanding that the evaporator (inside) leaks rather than the condenser (radiator) hence the smell of r134 permiating the cabin in the mornings...

Matt L · #12 04-22-2009, 10:14 AM

I've just not heard of many evaporator problems with the 210 (one, I think), but have heard of several instances of punctured condensers.

KarTek · #13 04-22-2009, 10:18 AM

I'd be thrilled if it was the condenser and not the evap...

Matt L · #14 04-22-2009, 10:42 AM

Quote:

Originally Posted by KarTek

I'd be thrilled if it was the condenser and not the evap...

No kidding. Outside of evacuation and recharge, the condenser is a half-hour job.

nhdoc · #15 04-22-2009, 10:56 AM

Well, I can speak as one who did have to replaced the condensor on my '98. I had the small leak both before and after the condensor failed (which caused a really fast leak) but when I replaced it I also replaced the hose between it and the receiver-drier which is another achilles heal on the W210 chassis. I also replaced the R-D at the same time. The total time to do it all was about 2-3 hours. It still leaks though. The leak is so small it is not easily detectable. My suspicion is that my leak is the radial seal on the compressor. It's so small you really don't see any evidence of it, even with a sniffer.

As far as evaporator failures go, they are not really all that common on the W210. There have been one or two reported but I certainly would not jump to a conclusion without knowing. Also, since the refrigerant has no odor it is unlikely that what you smell coming from the vents is a leak...more likely some mold spores or other contaminant in the system.