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-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 06-25-2010, 07:49 PM
051 051 is offline
Registered User
 
Join Date: Oct 2009
Posts: 57
AC help please!!!!

83 380 SEL
ambient temp in shop is 81
temp at vent with ac and fan full out 60 f
Low side psi 45
high side psi 250
See a fair amount of bubbles, looks like foam, in sight glass
temp of high side hose going into firewall 145
temp of low side hose coming out of firewall 87
top rad hose is 155 f
hose going into condenser is 146 f'
hose coming out of condenser is 143 f

new:
compressor
exp valve
dryer
system newly charged with r 12
Not sure about the amount of oil the mech put in but I am sure he added oil to the compressor before charging the system.

flushed and blew out all lines

heater hoses pinched off at firewall just to make sure no hot water is getting through firewall.

What am I missing here?

Any help will really be appreciated. If I can't do better than this I'm going to sell it and give up.

Thanks!
51
Reply With Quote
  #2  
Old 06-25-2010, 09:57 PM
Gilly's Avatar
Registered User
 
Join Date: Mar 2001
Location: Evansville WI
Posts: 9,616
Maybe low on freon? You have bubbles or foam and don't mention how much was put in. Usually bubbles and foam mean low freon and poor performance. Is the aux fan running? What is the output like when driving? Where are you getting R12, are you sure it's not some crappy drop-in refrigerant. The kind that goes BOOM?
Gilly
Reply With Quote
  #3  
Old 06-25-2010, 11:05 PM
dpetryk's Avatar
Electrons can do anything
 
Join Date: Sep 2001
Location: Houston, Texas
Posts: 1,071
Based on the temp readings on the condenser lines and the pressure on the high side, I would bet somebody used 134 instead of 12
__________________
I got too many cars!! Insurance eats me alive. Dave

78 Corvette Stingray - 3k
82 242 Turbo Volvo - Manual - 270k
86 300e 5 speed manual - 210k
87 420sel - 240k
89 560sl - 78k
91 420sel - 205k
91 560sel - 85k
94 GMC Suburban - 90k
97 Harley Davidson Heritage Softail - 25k
00 GMC Silverado 1 ton 30k
Reply With Quote
  #4  
Old 06-27-2010, 08:01 PM
051 051 is offline
Registered User
 
Join Date: Oct 2009
Posts: 57
can someone tell me what normal pressures and temps would be?
Also what is the max pressure on the high side. I want to add some more freon and see if the bubbles go away, I assume this will increase the pressures, but I don't know what the limit would be.
Thanks!
51
Reply With Quote
  #5  
Old 06-28-2010, 09:37 AM
dpetryk's Avatar
Electrons can do anything
 
Join Date: Sep 2001
Location: Houston, Texas
Posts: 1,071
There is no "normal". Everything depends on the ambient temperatures and air flow over the condenser & evaporator. If you have bubbles, then you need more freon. In my experience, after the bubbles go away the system needs about 1 lb. more to meet the specified requirements. Many people just add freon until the bubbles quit. I have found that is not always an accurate indication of the charge level. Usually it is good enough for most situations especially if you do not have the tools to accurately charge the system.
__________________
I got too many cars!! Insurance eats me alive. Dave

78 Corvette Stingray - 3k
82 242 Turbo Volvo - Manual - 270k
86 300e 5 speed manual - 210k
87 420sel - 240k
89 560sl - 78k
91 420sel - 205k
91 560sel - 85k
94 GMC Suburban - 90k
97 Harley Davidson Heritage Softail - 25k
00 GMC Silverado 1 ton 30k
Reply With Quote
  #6  
Old 06-28-2010, 11:31 AM
051 051 is offline
Registered User
 
Join Date: Oct 2009
Posts: 57
OK, I'm going to put more in and see what happens.
Thanks!
51
Reply With Quote
  #7  
Old 06-28-2010, 12:09 PM
Moderator
 
Join Date: Mar 1999
Location: Tucker, Ga USA
Posts: 12,153
Have you checked the fresh-air / recric flap for proper operation?

IF that door doesn't close all of the way the a/c duct temp can be 5-10 degrees off.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator
Reply With Quote
  #8  
Old 06-29-2010, 11:52 AM
Registered User
 
Join Date: Jul 2008
Posts: 1,236
MBDOC is right, especially when the hood is up if the recirc flap isn't closed, then you're sucking in super hot engine compartment air. Even if that is happening, you should see water puddles underneath the car if it is cooling at all.

Are you doing this at idle, or at 1500rpm? 1500rpm is a much better way to do this. If you still see bubbles in the sight glass, then you're still probably low on refrigerant.

Also, very important - After the parts were replaced, was the system totally vacuumed down? Air or moisture will kill the efficiency of the system.
__________________
-tp


1990 300SE "Corinne"- 145k daily driver - street modified differential - PARTING OUT OR SELLING SOON - PORTLAND OR. AREA - PM ME FOR DETAILS
1988 560SEL "Gunther"- 190K passes anything except a gas station
1997 S420 - 265k just bought it with a rebuilt trans. Lovely condition
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




All times are GMT -4. The time now is 08:31 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page