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Black on Black 1997 E420
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267 Posts
Those two pistons in photo, is it the stem of the plungers? Just pull them straight out or is there anymore to disassemble to access plungers? I've never cleaned them before.
 

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210.065
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the 2 pistons should be loose and bouncing
 

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Black on Black 1997 E420
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267 Posts
Bear with me about the questions, I'm a novice and don't want to needlessly damage anything. According to the link you sent me, I can remove the pistons from the very top of its brass colored posts?(with needle nose pliers) then the metal plate will come off along with pistons simultaneously? That's what #2 & #3 appears to have done.
 

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hi amani, don't worry, according to your own picture, you have not yet removed the metal plate at the bottom, you need to gently pry it off. The plunger will come with it.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,169 Posts
Checking for leaks

Earlier this year, I posted about the A/C on my '98 E320 malfunctioning. I got it working again by recharging using 1 can oil and a couple of R134a from Walmart. Pressure was up to about 14bar and A/C worked for 4 or 5 months. But, then it stopped working again. Pressure gone.

I was concerned that leak may be in evaporator and cost several arms and legs to repair. I was/am thinking of trading the car. So, I took it to a local A/C shop.

The shop evacuated system and pressure tested with high pressure nitrogen. This showed no leak. They then refilled with R134a and added dye. They left cat running for about an hour. They probed everything they can get at with their black light and freon sniffer. But they could not find a leak.

I asked them how they were able to get at the evaporator to check it. They said something about there being a port that can be removed for access? They also said there was some slight corrosion on condenser, but that it did not show a leak.

Plan is to go back in two weeks so they can recheck it.

Is there anything I can do myself in the meantime to try and find the leak (needs to be inexpensive :) )?
 

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'98 E430
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236 Posts
The dye will accumulate at the point of leakage. Start at the compressor and chase out the system looking for dye at each connection. Do this over the course of a few weeks and, if the leak is significant, you will find it. Leaks can be fixed but you have to locate them first. The dye is ordinarily a very bright green. You can also use a UV light and detect it.
 

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'72 350SL, '85 300D, '98 E320, '19 Subaru Outback (sold '14 GLK250)
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10,169 Posts
The dye will accumulate at the point of leakage. Start at the compressor and chase out the system looking for dye at each connection. Do this over the course of a few weeks and, if the leak is significant, you will find it. Leaks can be fixed but you have to locate them first. The dye is ordinarily a very bright green. You can also use a UV light and detect it.
Ok Thanks. Might see if I can get a cheap UV light.
 

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'98 E320
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16 Posts
The micro-saga continues.

Hi guys!
Still working on this darn AC system and I run across the blue wire to the compressor hanging down next to it. Yep, must've wiggled until it broke. At first I thought "halleluja!" I figured it out! not that it would have been all that tough. I get in the car, start it up, nothing. AAAAAARRRGG! When I apply 12V directly to the compressor, it starts right up! Sweet, don't have to buy one of those. When I test the blue terminal, it only reads slightly over 8V. Is this the normal range? Is 8V not enough to pull the clutch in? Is there a reset that I must do in order to clear some codes or anything after I hooked the wire back up to it? I just don't get it. If there is a reset, how do I do it? Thanks all.
Tony

(PS. just welded in two new Magnaflow cats yesterday- sounds very exotic now. not loud, just exotic)
 

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Hi guys!
Still working on this darn AC system and I run across the blue wire to the compressor hanging down next to it. Yep, must've wiggled until it broke. At first I thought "halleluja!" I figured it out! not that it would have been all that tough. I get in the car, start it up, nothing. AAAAAARRRGG! When I apply 12V directly to the compressor, it starts right up! Sweet, don't have to buy one of those. When I test the blue terminal, it only reads slightly over 8V. Is this the normal range? Is 8V not enough to pull the clutch in? Is there a reset that I must do in order to clear some codes or anything after I hooked the wire back up to it? I just don't get it. If there is a reset, how do I do it? Thanks all.
Tony

(PS. just welded in two new Magnaflow cats yesterday- sounds very exotic now. not loud, just exotic)
This should help:
http://www.benzworld.org/forums/w210-e-class/1448652-ac-compressor-how-check-if-getting.html
 

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'98 E320
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16 Posts
I very much appreciate the help. The blue wire going to the compressor does read that voltage is getting there. It may only be 8V, but power is getting there. How come 8V does not engage the clutch, but 12V does? More importantly, what would cause this wire to only deliver 8V? Also, the link to that thread did not contain any info as to how to delete the codes. Would that even matter if it is getting slightly less power? I don't know enough about these auto ac systems to troubleshoot a problem like this. Is there a way I can tell if the 8V going thru the wire is actually making contact with the compressor? This is a bit of a gut instinct that it may not be.
Thanks, Tony
 

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210.065
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I very much appreciate the help. The blue wire going to the compressor does read that voltage is getting there. It may only be 8V, but power is getting there. How come 8V does not engage the clutch, but 12V does? More importantly, what would cause this wire to only deliver 8V? Also, the link to that thread did not contain any info as to how to delete the codes. Would that even matter if it is getting slightly less power? I don't know enough about these auto ac systems to troubleshoot a problem like this. Is there a way I can tell if the 8V going thru the wire is actually making contact with the compressor? This is a bit of a gut instinct that it may not be.
Thanks, Tony
8V is not normal, should be 12V, you are right.
Why lowered? Short somewhere, old wire with increased resistance, etc.

Please update for vehicle and location.
 

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'98 E320
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16 Posts
The wire form the compressor goes into a loom and disappears into the wire abyss. Does anyone know where this wire ends up? In other words, what sends 12V to the AC compressor? As I posted earlier, I am not getting 12V, i'm only getting 8V to the compressor and it would be nice to be able to work my way back to the source. Even better, does anyone have an AC electrical schematic? Thanks
Tony
 

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E320/E250 Bluetec Ford F350 6.7l
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electrical schematic ?
Don't you know you are driving a computer?
It is the computer that is giving the signal. Lower voltage would indicate bad connection somewhere.
I would check the fuse first.
 

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'98 E320
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16 Posts
I have been looking for a fuse since I started this project. Anyone know where or what number? None of the cards say anything about AC compressor. I found blowers. No go.
 
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