Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes ShopForum > Technical Information and Support > ML, GL, G-Wagen, R-Class, Unimog, Sprinter

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 04-15-2005, 09:28 AM
Ron in SC's Avatar
Registered User
 
Join Date: Aug 2003
Location: Charleston, SC
Posts: 1,095
A/C Compressor: Does yours leak oil?

Check the bottom of you A/C compressor and see if it has refrigerant oil on it. Mine did, so I cleaned it with brake cleaner and will monitor it closely to see if I can tell where the leak originates. I suspect itís the upper control valve which is actually on the bottom of the compressor. See the photo below.

The valve has 3 o-rings on it and is held in by a snap ring which you can see in the photo. It seems like a likely place for a leak to develop. I think it can be removed with the compressor installed in the vehicle; of course you will need to evacuate the system first.

I noticed the oil on the compressor when I was inspecting the underside of the vehicle when I changed the oil. My A/C works fine but it must have lost a little R134a and I want to fix this problem so my compressor will last as long as possible.

I happened to check the price of a compressor and was told no remanufactured compressors are available for the one in the ML which is a Denso 7SB16C. A new one is about $1000. Hopefully a remanufactured unit could be found somewhere.

Worst case would have the A/C compressor seize and have that wonderful serpentine belt will travel over the pulley on the A/C clutch which will not be moving. That may very well equal shredded belt. Which means your stranded.
Attached Thumbnails
A/C Compressor: Does yours leak oil?-dsc01883.jpg  
Reply With Quote
  #2  
Old 04-16-2005, 11:41 PM
Jim in Phoenix
 
Join Date: Aug 2004
Location: Phoenix, AZ
Posts: 149
AC compressor, etc.

<
The valve has 3 o-rings on it and is held in by a snap ring which you can see in the photo. It seems like a likely place for a leak to develop. I think it can be removed with the compressor installed in the vehicle; of course you will need to evacuate the system first.

I noticed the oil on the compressor when I was inspecting the underside of the vehicle when I changed the oil. My A/C works fine but it must have lost a little R134a and I want to fix this problem so my compressor will last as long as possible.

I happened to check the price of a compressor and was told no remanufactured compressors are available for the one in the ML which is a Denso 7SB16C. A new one is about $1000. Hopefully a remanufactured unit could be found somewhere.

Worst case would have the A/C compressor seize and have that wonderful serpentine belt will travel over the pulley on the A/C clutch which will not be moving. That may very well equal shredded belt. Which means your stranded.>>

Ron,

I believe you will find the oil leak is originating above the AC compressor. On my 98 ML320, I found that small cover with the allen socket screw in the center, was leaking engine oil. This is on the front of the engine, driver's side. The O-ring that seals it to the block was hard and ineffective.

An interesting aside, this cover only leaks when the engine is running. When the engine is shut off, I believe that this cover leaked air into the engine block, allowing the engine oil to drain back to the pan. Some of the startup clatter that many of us hear is due to lack of engine oil in the lifter passages.

I believe my engine got noticably quieter, on a cold start, after I fixed this leak. Just my opinion, YMMV.

As to your comment about the AC compressor siezing and frying the belt, Mercedes has had a speed monitor on their AC compressor since about '87. The compressor clutch is immediately released if the ECU notices the compressor running at a speed less than normal. Some who have washed their engines have experienced AC compressor lockout due to wet belts. Turning the key off resets the lockout, asuuming the compressor has stopped slipping.

Regards,

Jim in Phoenix
Attached Thumbnails
A/C Compressor: Does yours leak oil?-im000668.jpg  

Last edited by jfreezn; 04-16-2005 at 11:54 PM. Reason: add a picture of leaking plate
Reply With Quote
  #3  
Old 04-17-2005, 08:39 AM
Ron in SC's Avatar
Registered User
 
Join Date: Aug 2003
Location: Charleston, SC
Posts: 1,095
Jim,

That's a good lead I'll check that area carefully. Right now everything is clean so I can not say for sure where the oil that collected on bottom of the compressor orginated. It did look like compressor oil, as it was quite clear looking and uncontaminated. Maybe it was power steering oil, but I checked the level and it was right where it should be.

As far as the Mercedes putting that speed monitor on their AC compressors, that good news. For me those serpentine belts are nothing but trouble. I prefer to change and adjust individual belts myself. And should one break you change can it on the side of the road yourself with minimal effort and very few tools.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
excessive oil consumption ML320 pmount ML, GL, G-Wagen, R-Class, Unimog, Sprinter 26 02-14-2012 10:13 PM
Oil in the air filter. 617 engine. More than normal. dmorrison Diesel Discussion 5 11-13-2004 09:46 PM
Demystifying Oil - General high-level info about oil haasman Tech Help 6 04-21-2004 03:28 AM
Oil Change Frequency mrbroche Tech Help 34 06-01-2001 12:03 AM



All times are GMT -4. The time now is 05:02 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page