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 > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 04-26-2010, 08:18 PM
GreenMedallion's Avatar
Registered User
 
Join Date: Apr 2007
Location: Los Angeles, CA
Posts: 79
A/C - help trouble shooting, fixing

Hi all. I searched and searched, but could not find the right answer (not to mention when I search for "A/C" or "AC" no results show.)

My 1979 300TD n/a wagon has never, since I've had it, had a working A/C. Heat blows great, and blows well on A/C settings "hi" or "low" but nothing cold. Orig. owner mentioned the system needs to be recharged. If that is all that needs to happen, is there some way to confirm that it just needs to be recharged, short of just recharging it?

I also notice the following when I put the A/C "on". The fan blows well, but when I push the "on" button for the A/C, and hold it in, some other fan kicks in, but does not stay on when I am not holding down the "on" button. Is there something wrong with the switch? Or bigger problems?

I am trying to sell this wagon, but if I get the A/C working, may just hang on. Reason for selling - moving to very humid climate where A/C will be a necessity.

Thanks.

__________________
1979 300TD wagon (non-turbo)
266,000+
Reply With Quote
  #2  
Old 04-26-2010, 10:13 PM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,835
search and read all threads titled evil servo.
it's good your settings work in heat. and the fan works. does any air blow out the center vents when you set it to A/C and have the dial set to min?
if not, go back to checking the evil servo threads.
I had a 79 TD. fun little car. never got the A/C working.
Reply With Quote
  #3  
Old 04-26-2010, 11:02 PM
GreenMedallion's Avatar
Registered User
 
Join Date: Apr 2007
Location: Los Angeles, CA
Posts: 79
Thanks, will read the evil servo threads.


To answer your question - Air does come out the center w/ AC on.

No dials on this one - my climate control looks like this -
__________________
1979 300TD wagon (non-turbo)
266,000+
Reply With Quote
  #4  
Old 04-26-2010, 11:05 PM
Registered User
 
Join Date: Jun 2008
Location: Orlando, FL
Posts: 1,269
Read all of this:

http://www.peachparts.com/shopforum/showthread.php?t=240530
Reply With Quote
  #5  
Old 04-26-2010, 11:09 PM
79Mercy's Avatar
Registered User
 
Join Date: Mar 2008
Location: Florida
Posts: 4,131
OT: but wow thats the first diesel other than a coupe(300CD) i have ever seen with burl wood.

What is your VIN number?
__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
Reply With Quote
  #6  
Old 04-26-2010, 11:25 PM
GreenMedallion's Avatar
Registered User
 
Join Date: Apr 2007
Location: Los Angeles, CA
Posts: 79
Sorry, not a pic of my interior, just found online for convenience.

From this page - http://commons.wikimedia.org/wiki/File:Climate_Control_MB_w123.jpg

Looks like it was uploaded from Germany, so possible a motherland-only special?
__________________
1979 300TD wagon (non-turbo)
266,000+
Reply With Quote
  #7  
Old 04-26-2010, 11:26 PM
79Mercy's Avatar
Registered User
 
Join Date: Mar 2008
Location: Florida
Posts: 4,131
Burl wood came on some early gasser W123's and on some early diesel coupes.
__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
Reply With Quote
  #8  
Old 04-27-2010, 01:00 AM
GreenMedallion's Avatar
Registered User
 
Join Date: Apr 2007
Location: Los Angeles, CA
Posts: 79
Funny - I just noticed 79mercy and colincoon are in FL. I am hoping to get the AC working as I may be moving from Los Angeles to St. Augustine later this year.

Any chance you guys know a good MB mechanic in those parts?
__________________
1979 300TD wagon (non-turbo)
266,000+
Reply With Quote
  #9  
Old 04-27-2010, 08:33 AM
92 300D 2.5L OBK #59
 
Join Date: Feb 2007
Location: Central FL
Posts: 1,108
pierre
__________________
92 300D 2.5L OM602 OBK #59
Reply With Quote
  #10  
Old 04-27-2010, 08:41 AM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,835
... that dial on the left side of the vertical buttons... blue numbers are cool. should have a min setting.
it's a very good sign that you have air out the center vents. your servo appears to be working. I'd have the system leak checked, and possibly, just head off issues, and replace the expansion valve, and charge it up and see if the compressor cools!
Reply With Quote
  #11  
Old 04-27-2010, 09:28 AM
69shovlhed's Avatar
Registered User
 
Join Date: Apr 2010
Location: Sterling, VA.
Posts: 286
does the compressor clutch lock up when you turn on the ac? you can't trouble shoot it if its empty. evacuate and charge the system w/ r134. all you need are the adapters to do this, don't let the shop tell you that you need all this new ****. have them put some dye in it so if there is a leak it will be easy to find. if you fill it and it works, done deal. if it don't work, put 12v straight to the compressor clutch to see if it will lock. don't leave it jumped for more than about 15 seconds, unless you have gauges hooked up, pressure can go way too high if there is a restriction.
__________________
1984 300TD "MAX" 303K+ still going...
fast '70 Chevelle 200k+
home built Shovelhead chopper
Reply With Quote
  #12  
Old 04-27-2010, 10:36 AM
Registered User
 
Join Date: Sep 2001
Location: central Texas
Posts: 17,281
DO NOT PUT DYE INTO YOUR AC SYSTEM.
It can stop up the Txvalve and other small stuff..

AND

it will NOT HELP YOU FIND A LEAK IN YOUR EVAPORATOR....
Just say NO....

There are HUGE numbers of good threads which tell the proper way to do this stuff....
if it is probable you have a leak there is a legal way to check it.. in the archives available by using the search feature...
Reply With Quote
  #13  
Old 04-27-2010, 01:24 PM
GreenMedallion's Avatar
Registered User
 
Join Date: Apr 2007
Location: Los Angeles, CA
Posts: 79
Here is what seems like a good game plan -

1) evacuate/flush system
2) replace expansion valve
3) recharge w/ Freeze-12
4) hope I get cold air!

Since I am pressed for $$, would there be any harm in skipping 1+2 and just trying to recharge the system? Would be only possible loss be a few cans of Freeze-12, or would that cause other damage?
__________________
1979 300TD wagon (non-turbo)
266,000+
Reply With Quote
  #14  
Old 04-27-2010, 01:31 PM
Registered User
 
Join Date: Sep 2001
Location: central Texas
Posts: 17,281
" HOPE " is not really one of the concepts we use for dealing with AC systems... as they are really about pure physics. If you violate a rule it will bite you either with having to do it over again, or blowing your compressor or something else which will waste time and money ...
One was great.
Two can probably be skipped if it is clean.. however, to do a proper flush you will want to use the old expansion valve as a ' tool' and so you will need a new one.
Three is a very bad idea.. lots of threads about alternative refrigerants..
USE either R12 or R134a.
If you are ready to accept those premises post and let us know.. we can get you to where you need to go in a logical manner... and will strive for ' as cheap as possible ,but not cheaper )... in other words... you can shoot yourself in the foot trying to cut too many or certain important corners..
Reply With Quote
  #15  
Old 04-27-2010, 03:23 PM
vstech's Avatar
DD MOD, HVAC,MCP,Mac,GMAC
 
Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,835
Quote:
Originally Posted by GreenMedallion View Post
Here is what seems like a good game plan -

1) evacuate/flush system
2) replace expansion valve
3) recharge w/ Freeze-12
4) hope I get cold air!

Since I am pressed for $$, would there be any harm in skipping 1+2 and just trying to recharge the system? Would be only possible loss be a few cans of Freeze-12, or would that cause other damage?
um, no.
the flush will remove any oil from the lines/coils.
there will then be no oil to speak of in the system, so putting fr12 in there will kill the compressor in just a few minutes...
IF you are set to use fr12, you better get a complete kit with oil designed for the refrigerant blend. and you better put large warning stickers on the car showing freeze 12 blend is installed in the system!
I would do this order.
1 flush and clean lines and coils.
2 replace the expansion valve.
3 pressurize with dry nitrogen and verify leak free system.
4 replace receiver/drier
5 add correct volume of correct oil to lines for the refrigerant used.
6 evacuate system to 1000 microns or a solid evac if no micron gauge is used.
7 recharge with correct volume of refrigerant.
8 start system and test operation of blower, aux fan, and check system operation.
9 enjoy cool a/c

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!
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 03:43 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page