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 07-15-2005, 05:31 PM
Registered User
 
Join Date: May 2004
Location: Ann Arbor, MI
Posts: 19
95 300D Air Conditioning Quit

I just had my 1995 300D into the shop for new V belt and they
replaced all the belt tensioner parts. Last weekend while I came
to a stop lite I heard some screetching of the belt. Subsequently,
the air conditioner became intermittent. Now it always blows warm
air and the belt vibration that was supposed to be fixed by replacing
the belt tensioner is back. Any ideas?

Brian

__________________
---------------------------
1995 E300D Black 170K miles
Reply With Quote
  #2  
Old 07-15-2005, 09:57 PM
whunter's Avatar
Moderator
 
Join Date: Dec 2003
Location: Metro Detroit, Michigan
Posts: 17,357
Best guess:

The compressor locked up.
__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Prototype Vehicle build.
Prototype Fleet Durability
Prototype vehicle instrumentation.
Technical Quality Auditor.
Automotive Technical Writer

1973 300D
1973 309D - stolen
1978 280SE
1980 240D
1983 300D
1984 190D
Reply With Quote
  #3  
Old 07-16-2005, 01:53 AM
Registered User
 
Join Date: May 2004
Location: Ann Arbor, MI
Posts: 19
Compress Lockup?

It seems to be intermittent. Some mornings it works and others it doesn't. New compressor needed or might there be some other possibility. If it does need a new compressor, is there a recommended Internet site to purchase one?

Brian
__________________
---------------------------
1995 E300D Black 170K miles
Reply With Quote
  #4  
Old 07-16-2005, 04:18 AM
mbonly's Avatar
603 aficionado
 
Join Date: May 2005
Location: nyc
Posts: 189
the problem might be related to the belt itself , in my 87 300d if theres slippage then the compressor cut off relay will cut out the compressor if the difference between eng speed and compressor speed is more than 30% for a certain amount of time (in seconds, dont remember how long) yours is probably the same or similar, this is done to protect the eng in case the compressor locks up. You mentioned the problem is intermitent so I dont think the comp is locked up otherwise you'll see the alt light come on the dash and lose power steering since that belt will definitely self destruct or jump the pulley if the compressor did lock up
__________________
87 300d Turbo 241K with original #14 head (blue)
87 300d Turbo 198K will run great again someday (silver)
84 300sd sold ( buyer drove it to Paraguay )
Reply With Quote
  #5  
Old 07-16-2005, 11:20 AM
LarryBible
Guest
 
Posts: n/a
mbonly is probably right on this. This is a subject that has been written about ALOT here on mshop. A search will give you more reading than you will have time to cover.

Good luck,
Reply With Quote
  #6  
Old 07-16-2005, 12:18 PM
pberku's Avatar
Registered User
 
Join Date: Oct 2003
Location: Montreal, Canada
Posts: 737
Have someone start the engine while you look at the AC compressor. If it turns on for 1 second or so and than immediately turns off than its most definitely shutting off because the speed sensor in the AC detected a mismatch between the speed of the AC compressor and the speed of the engine. The AC compressor will than not start again, unless you turn your engine off and on. The same cycle will likely than be repeated.

This, as other have said is most likely due to a slipping belt. Fix the belt and you should be OK.

Phil
__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]
Reply With Quote
  #7  
Old 07-17-2005, 11:27 AM
whunter's Avatar
Moderator
 
Join Date: Dec 2003
Location: Metro Detroit, Michigan
Posts: 17,357
Thumbs up Let's meet tonight..

Quote:
Originally Posted by bhackett
It seems to be intermittent. Some mornings it works and others it doesn't. New compressor needed or might there be some other possibility. If it does need a new compressor, is there a recommended Internet site to purchase one?

Brian
I will be in Ann Arbor this evening to visit family.
You have PM..
Reply With Quote
  #8  
Old 07-26-2005, 09:51 PM
Registered User
 
Join Date: May 2004
Location: Ann Arbor, MI
Posts: 19
300D Compressor Intermittent

The saga continues. I took the 300D to both a local garage and
the dealership over the last couple of weeks. The local garage
looked at all the pressures (were fine) and suggested that the
dealership should see it because they could pull the codes and
be able to find the cause sooner.

I had the car at the dealership all day and the technician never
saw the compressor (clutch) shut off by itself. I went to pick
up the car, turned it on, and the compressor stayed off. I went
and got the technician who looked and looked and eventually
said it might be the RPM sensor on the compressor. He would
tear down the compressor and for $500 to $1000 would fix it.

I'm not so sure he's correct. The compressor does come on again
when you are driving. I noticed that when I was driving home.
All of sudden it got cool again. So.. I don't think it is the RPM
sensor because I didn't have to restart to reset the compressor.

One suggestion was the Klima module was faulty. I've been trying
to locate it in my 1995 300D. It isn't behind the battery. The
battery in my car is right up against the firewall. My sedan type
is 124.131 and the engine is a 606.910 (3L).

There's got to be a better way to diagnose the problem than
replacing a bunch of parts until you find it.

Brian
__________________
---------------------------
1995 E300D Black 170K miles
Reply With Quote
  #9  
Old 07-27-2005, 01:33 AM
pberku's Avatar
Registered User
 
Join Date: Oct 2003
Location: Montreal, Canada
Posts: 737
Brian,

I have the same car, and the KILMA relay is indeed located behind the Battery. Its behind the black plastic cover at the back of the battery. There are several other relays there as well.

You are right, the Mercedes manual does say that the AC compressor will not restart (after it has shut down because it sensed an RPM variance), until the engine is turned off and on again, BUT, it will restart on its own if the shutdown was caused by faulty wiring to the speed sensor. This can occur if the speed sensor wires are intermittently shorting, opening or grounding. In that case, the AC compressor will come back on as soon as the intermittent wiring fault fixes itself. Basically what I am saying is that the system seems to be capable of distinguishing between an RPM variance and a wiring malfunction. In the case of an RPM variance the compressor will not restart until you shut down the engine and restart it. In the case of a wiring fault the compressor will restart as soon as the wiring fault is removed.

I know this for a fact, as I had intermittent defective wiring between the AC speed sensor and the KILMA switch. These two particular wires carry a digital signal, and one of the two speed sensor wires was intermittently grounding, causing the digital signal to be attenuated. (The infamous wiring harness problem) the compressor would then go off and come on intermittently. This, without shutting down the engine. I fixed the problem by running two new wires.

There are several other possibilities. One being defective wiring to the auxiliary fan. This will cause the AC compressor to intermittently shut off as well.

Phil
__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

Last edited by pberku; 07-27-2005 at 01:46 AM.
Reply With Quote
  #10  
Old 07-27-2005, 04:21 PM
Registered User
 
Join Date: May 2004
Location: Ann Arbor, MI
Posts: 19
95 300D Air Conditioning Quit

Thanks for setting me straight on the location of the Klima module. It looked
like the firewall until I touched it and found it to be fiber instead of metal.
Yes I do see the relays now. I keep looking at the AllData documents but
they don't show any protective shrouds. I'm still not exactly sure which
module it is. There is a tall module and then 2 shorter ones behind it.

At lunch time today I drove it home and was amazed to see the air
conditioner work 100% all the way home and back again. The outside
air temperature was about 68F. A far cry from the 90+ temperatures
that we were getting the last couple of weeks while the a/c was
failing.

Does that information help? Could it be something other than the Klima?

Brian
__________________
---------------------------
1995 E300D Black 170K miles
Reply With Quote
  #11  
Old 08-05-2005, 05:13 PM
Registered User
 
Join Date: May 2004
Location: Ann Arbor, MI
Posts: 19
95 300D Air Conditioning Quit

I've been driving it around for the last while hoping it
would just plain fail. It seems to be humidty related.
On dryer days it works pretty well. When it gets
humid it starts acting up.

Today it was a dryer day and it worked flawlessly
until I took it through a car wash. While water was
spraying under the car it went off. As soon as the
attendent finished wiping it down, it came back on
(engine was running all the time) and worked flawlessly
the rest of the day.

__________________
---------------------------
1995 E300D Black 170K miles
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
300TD Air Conditioning Problems flbiggs Diesel Discussion 10 08-17-2007 08:20 PM
W210 Air Conditioning System Fault Codes JimSmith Tech Help 15 01-21-2005 12:38 AM
Air Conditioning Problems very tired Tech Help 1 07-29-2003 08:53 AM
300D Turbo Air Conditioning jconley Diesel Discussion 2 05-11-2003 05:36 PM
1980 300D Air Conditioning Dan Fitzpatrick Tech Help 4 04-05-2001 03:39 PM



All times are GMT -4. The time now is 06:50 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, 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