Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)

E39 (1997 - 2003)
The BMW 5-Series (E39 chassis) was introduced in the United States as a 1997 model year car and lasted until the 2004 when the E60 chassis was released. The United States saw several variations including the 525i, 528i, 530i and 540i. -- View the E39 Wiki

Reply
 
Thread Tools Display Modes
  #1  
Old 05-28-2011, 04:00 PM
jetpilot10's Avatar
jetpilot10 jetpilot10 is offline
JETPILOT10
Location: Frisco Texas
 
Join Date: Mar 2004
Posts: 197
Mein Auto: 2000 BMW 540I
Thumbs up BMW E39 A/C Pressure Readings Advice Sought

I have noticed recently my A/C system has not been keeping pace with the rising temps in the Dallas area and today was the final straw. I have a Black 540i and my car sat in the sun for about 6 hours and was like an oven for the hour drive home. I stopped into AutoZone and picked up a can of R134a with dye trace to see if I can locate any leak. The system has not been touched or topped off in the last 5 years. It has been running flawless since I had a compressor replaced over 5 years ago. The system still runs as should, i.e. compressor cycling, the Aux fan increasing and decreasing in speed as it should, just been getting warmer air our of vents.

Using quality manifold gauge set initial readings showed approx 170 psi High / 28 psi Low. Air out of center vents was cool at best and not anywhere near as cold as it was a year ago, so I am sure there is a small leak n the system somewhere.

I have the Bentley manuals but they do not publish even any target pressure settings. So I set out on the board searching for pressure settings. I stumbled across some basic reference numbers in a range of 170-320 psi High and 14-32 Low, so off I went.

Current weather in Dallas while adding One (1) - 12 ounce can of R134a Refrigerant with DYE trace: Outside Temp: 93 Degrees / Dew point 69 Degrees / Relative Humidity 47%

Final readings after letting car idle for 15 minutes, adding Freon, and letting idle an additional 15 minutes after can was introduced:

High Pressure side: 275 psi
Low Pressure side: 33 psi

A/C system set to lowest setting, which in the E39 is 60 degree’s, highest fan speed, Three (3) Blue Dots on the center vents. After adding refrigerant I was getting 50-53 Degree’s on the temperature gauge that was placed in the Center vents on high fans speeds and at mid level fan speeds the temp would drop to 40-44 Degrees. I was using a Pyrex Digital Thermometer.

Are there any experienced HVAC guys on the board that can tell me if this is close enough for pressure readings and temps, or should I be looking at getting the system serviced further?
__________________

Jetpilot10
2000 540i Sport
Corporate Pilot / Aerobatic Instructor
Competition and Airshow Pilot
WestWind II (IA-Jet) & King Air 350 (BE-300)
www.tail-wheel.com
Reply With Quote
Advertisement
  #2  
Old 05-28-2011, 04:24 PM
dvsgene dvsgene is offline
Search, Read, THEN Ask
Location: "Empire State" of Mind
 
Join Date: Sep 2002
Posts: 2,614
Mein Auto: 98 540i M62 3.15
Good write up and detail but based on your ambient temperature of 93deg F. the low side should read closer to 50PSI

Typically the R134a refill kits come with an adjustable guage to adjust for PSI depending on ambient temps. Unless you bought JUST the can.

See here:
http://www.idqusa.com/faqs.php?faq=7...8&parent_id=18
Reply With Quote
  #3  
Old 05-29-2011, 12:27 AM
DHoang's Avatar
DHoang DHoang is offline
Gearhead
Location: Austin, Texas
 
Join Date: Dec 2008
Posts: 985
Mein Auto: '98 528i, '82 323i
My readings at 95deg F, 80% humidity shows
30psi, low
275 psi, hi
blower motor set to midway, 60deg.
38 deg. F , vent temp

I think your settings are fine the way it is, as I've been told, and have read here and elsewhere, that
BMW A/C units operate at lower psi than most units on the market.
__________________
http://www.bimmerfest.com/forums/picture.php?albumid=4132&pictureid=24642

Last edited by DHoang; 05-29-2011 at 12:37 AM.
Reply With Quote
  #4  
Old 05-29-2011, 12:59 PM
Jimmys 530i Jimmys 530i is offline
Officially Welcomed to the 'Fest
Location: Conyers, GA
 
Join Date: Feb 2011
Posts: 811
Mein Auto: 2003 530i
That is very close. I would not mess with it any more. I often charge systems, and the most common thing done by home mechanics is overcharging. They try to get it as cold as possible, and overcharge it so the pressure switch cuts out, and the compressor does not kick on.
__________________
2004 BMW 330ci Silvergray Sport Package, Cold Package, Xenon Headlamps, Premium Package, 6 Speed Manual, Build Date 9/03

Sold - 2003 325i Sedan Japanrot 5 Speed 8k Xenon Headlamps Build Date 11/02
Reply With Quote
  #5  
Old 05-29-2011, 01:49 PM
Burning2nd Burning2nd is offline
Under the lift arms
Location: Under the lift arms
 
Join Date: Aug 2010
Posts: 4,274
Mein Auto: E39 540, E36 328is, E83x3
don't make me go down stairs and get you the page number.. it's in the Bentley...
__________________
Specializing In BMW, Audi, Mercedes Benz ,Volkswagen, Volvo
Reply With Quote
  #6  
Old 05-31-2011, 03:00 PM
jetpilot10's Avatar
jetpilot10 jetpilot10 is offline
JETPILOT10
Location: Frisco Texas
 
Join Date: Mar 2004
Posts: 197
Mein Auto: 2000 BMW 540I
Bentley Manuals

I have driven around a few days and the ac is cooling nicely. I am going to leave as is. I also looked thru both Bentley books and could not locate pressures, just the warning that BMW service center should handle.

Thanks for the input guys it is most appreciated.

Dave
__________________

Jetpilot10
2000 540i Sport
Corporate Pilot / Aerobatic Instructor
Competition and Airshow Pilot
WestWind II (IA-Jet) & King Air 350 (BE-300)
www.tail-wheel.com
Reply With Quote
  #7  
Old 05-31-2011, 03:46 PM
jburnham jburnham is offline
Officially Welcomed to the 'Fest
Location: CT
 
Join Date: Oct 2007
Posts: 298
Mein Auto: 2003 540iA, 2001 540i/6
I think if you have too much oil in there, you'll get the same results you see. The excess oil acts like a heat sink and accumulates in places that interfere with cooling. I think I'm in that boat. The pressures are good and the system mostly works, but just doesn't get cool enough fast enough. I'm planning to have the A/C drained, replace the oil and vacuumed. The big question is how much oil should they put in? Most advice is to drain it, measure it, and put the same back in plus a little more. If it might already be overfilled, how do you rectify that?
Reply With Quote
  #8  
Old 05-31-2011, 03:57 PM
540Sportauto 540Sportauto is offline
I can't feel my face
Location: San Diego, CA
 
Join Date: Nov 2008
Posts: 26
Mein Auto: 540i sport auto
Quote:
Originally Posted by jburnham View Post
I think if you have too much oil in there, you'll get the same results you see. The excess oil acts like a heat sink and accumulates in places that interfere with cooling. I think I'm in that boat. The pressures are good and the system mostly works, but just doesn't get cool enough fast enough. I'm planning to have the A/C drained, replace the oil and vacuumed. The big question is how much oil should they put in? Most advice is to drain it, measure it, and put the same back in plus a little more. If it might already be overfilled, how do you rectify that?
Why do you think it is overfilled with refrigerant oil? Did somebody just do work on it?
Reply With Quote
  #9  
Old 05-31-2011, 04:03 PM
dvsgene dvsgene is offline
Search, Read, THEN Ask
Location: "Empire State" of Mind
 
Join Date: Sep 2002
Posts: 2,614
Mein Auto: 98 540i M62 3.15
Quote:
Originally Posted by jburnham View Post
If it might already be overfilled, how do you rectify that?
Release the excess. However, you are supposed to release to a r134a recapture system but I am sure many people just release to the air despite it being illegal.
Reply With Quote
  #10  
Old 05-31-2011, 05:13 PM
Burning2nd Burning2nd is offline
Under the lift arms
Location: Under the lift arms
 
Join Date: Aug 2010
Posts: 4,274
Mein Auto: E39 540, E36 328is, E83x3



send from space command
__________________
Specializing In BMW, Audi, Mercedes Benz ,Volkswagen, Volvo
Reply With Quote
  #11  
Old 05-31-2011, 06:04 PM
Fudman's Avatar
Fudman Fudman is offline
Officially Welcomed to the 'Fest
Location: Sudbury, MA
 
Join Date: Apr 2007
Posts: 6,225
Mein Auto: '02 530i Sport auto
Quote:
Originally Posted by Burning2nd View Post



send from space command
+1, BMW does not specify a system pressure, it specifies weight of R134A in the system. Hence, arbitrarily adding R134A will likely put too much in, resulting in an AC that does not operate properly (ask me how I know). The proper procedure is to drain your system, pull a vacuum and then add the proper amount of R134A.
Reply With Quote
  #12  
Old 05-31-2011, 06:22 PM
dvsgene dvsgene is offline
Search, Read, THEN Ask
Location: "Empire State" of Mind
 
Join Date: Sep 2002
Posts: 2,614
Mein Auto: 98 540i M62 3.15
Quote:
Originally Posted by Fudman View Post
+1, BMW does not specify a system pressure, it specifies weight of R134A in the system. Hence, arbitrarily adding R134A will likely put too much in, resulting in an AC that does not operate properly (ask me how I know). The proper procedure is to drain your system, pull a vacuum and then add the proper amount of R134A.
^^^^^THIS. But NOT DRAIN, RECAPTURE which requires a specialist.
Reply With Quote
  #13  
Old 05-31-2011, 07:38 PM
jburnham jburnham is offline
Officially Welcomed to the 'Fest
Location: CT
 
Join Date: Oct 2007
Posts: 298
Mein Auto: 2003 540iA, 2001 540i/6
Thank you Burning2nd for going to the trouble of scanning. I'm not as worried about the coolant - once they pull a vacuum, it will be back to 0 grams and it's straightforward to either add by weight or by pressure. The nearly impossible thing to figure out is how much PAG 46 oil to add to a system that is possibly over-oiled (or then again, maybe it's under-oiled). It would be comforting if we could recover the coolant, and then open the drain on the compessor and know that all but X ounces of oil will be evacuated. I would then know how much oil to add to get it to the correct amount. Any educated guesses?
Reply With Quote
  #14  
Old 05-31-2011, 09:11 PM
bmw_lover85 bmw_lover85 is offline
Officially Welcomed to the 'Fest
Location: Indiana
 
Join Date: Dec 2010
Posts: 178
Mein Auto: 97 528i manual.
Just to double check, this car takes PAG oil in the AC system?

So if I want to add oil, I go to Autozone and get PAG oil can?

My AC compressor is loud and I want to try to add oil to it before replacing the compressor...
Reply With Quote
  #15  
Old 06-01-2011, 01:46 AM
Burning2nd Burning2nd is offline
Under the lift arms
Location: Under the lift arms
 
Join Date: Aug 2010
Posts: 4,274
Mein Auto: E39 540, E36 328is, E83x3
anytime... let me know if you need anything else... its all in volume 2

im sure there's more on the oil. ill look and get back later tonight
__________________
Specializing In BMW, Audi, Mercedes Benz ,Volkswagen, Volvo

Last edited by Burning2nd; 06-01-2011 at 01:47 AM.
Reply With Quote
  #16  
Old 06-03-2011, 11:39 PM
bmw_lover85 bmw_lover85 is offline
Officially Welcomed to the 'Fest
Location: Indiana
 
Join Date: Dec 2010
Posts: 178
Mein Auto: 97 528i manual.
Quote:
Originally Posted by Burning2nd View Post
anytime... let me know if you need anything else... its all in volume 2

im sure there's more on the oil. ill look and get back later tonight


Did you find out anything new about the oil? I went to the dealer and they don't sell the oil... BUT I forgot to ask about what oil it takes lol.
I'm sure the clerk won't answer though... He is the rudest clerk I have ever seen... Almost all of them working in this dealer in Indianapolis. They will only smile at you if you're driving '04+ BMW's.
Reply With Quote
  #17  
Old 06-04-2011, 03:38 AM
Burning2nd Burning2nd is offline
Under the lift arms
Location: Under the lift arms
 
Join Date: Aug 2010
Posts: 4,274
Mein Auto: E39 540, E36 328is, E83x3
let me look look i forgot.. give me a second...

well.. it all just says the same thing... pag oil...

i would do what past ac jobs tell me...

assuming the system is clean and dry because you evacuated it with a pump (like a robbin air)

i would replace almost 3/4 can of pag, then figure out your weight of refrigerant

i dont know what the weight of the cans are but you have to estimate the weight and then watch your gauges
__________________
Specializing In BMW, Audi, Mercedes Benz ,Volkswagen, Volvo

Last edited by Burning2nd; 06-04-2011 at 03:48 AM.
Reply With Quote
  #18  
Old 06-04-2011, 04:44 AM
jburnham jburnham is offline
Officially Welcomed to the 'Fest
Location: CT
 
Join Date: Oct 2007
Posts: 298
Mein Auto: 2003 540iA, 2001 540i/6
Thanks again Burning2nd. We'll probably do this:

1. Recover existing refrigerant to near zero pressure (no vacuum) - possibly put a tiny charge in to ensure we don't draw in contaminents.
2. Open the drain on the compressor and drain it out
3. Pull as much vacuum for as long as we can manage
4. 6? ounces PAG 46 oil
5. 750 grams 134a and then monitor temperatures and add up to 25 grams more
Reply With Quote
  #19  
Old 06-04-2011, 04:54 AM
Burning2nd Burning2nd is offline
Under the lift arms
Location: Under the lift arms
 
Join Date: Aug 2010
Posts: 4,274
Mein Auto: E39 540, E36 328is, E83x3
that will put you right on target....

best of luck... let us know how it works...
__________________
Specializing In BMW, Audi, Mercedes Benz ,Volkswagen, Volvo
Reply With Quote
  #20  
Old 06-04-2011, 05:13 AM
cn90 cn90 is offline
Officially Welcomed to the 'Fest
Location: Omaha NE
 
Join Date: Mar 2006
Posts: 12,855
Mein Auto: 1998 528i 5-sp 140K+
In my other cars (Volvo, Honda Odyssey), low side pressure of 30-35 psi is fine.
The Honda technical manual says if you can get a gradient of 36-40F you are OK.
Let's say:
- Under the tree (no direct sun), ambient temp of 90F.
- Blower Fan at 60% of max speed
- The output at the center vent should be 50F or so. (90F - 40F = 50F).

Just a generic rule of thumb.
Reply With Quote
  #21  
Old 06-04-2011, 05:33 AM
cn90 cn90 is offline
Officially Welcomed to the 'Fest
Location: Omaha NE
 
Join Date: Mar 2006
Posts: 12,855
Mein Auto: 1998 528i 5-sp 140K+
Quote:
Originally Posted by jetpilot10 View Post
...Are there any experienced HVAC guys on the board that can tell me if this is close enough for pressure readings and temps, or should I be looking at getting the system serviced further?
jetpilot,

"Jimmy 530i" is an AC tech:

http://www.bimmerfest.com/forums/sho...d.php?t=545938

Send him a PM etc.
Reply With Quote
  #22  
Old 06-04-2011, 09:02 AM
bmw_lover85 bmw_lover85 is offline
Officially Welcomed to the 'Fest
Location: Indiana
 
Join Date: Dec 2010
Posts: 178
Mein Auto: 97 528i manual.
Quote:
Originally Posted by Burning2nd View Post
let me look look i forgot.. give me a second...

well.. it all just says the same thing... pag oil...

i would do what past ac jobs tell me...

assuming the system is clean and dry because you evacuated it with a pump (like a robbin air)

i would replace almost 3/4 can of pag, then figure out your weight of refrigerant

i dont know what the weight of the cans are but you have to estimate the weight and then watch your gauges

Thank you Burning2nd. I don't want to evacuate the system... Is that ok?
I thought I can let some pressure out and then put some oil. My AC is cold... It just make knocking noise from the compressor... It sounds like an impact gun but a little bit lower in sound.
Reply With Quote
  #23  
Old 06-04-2011, 07:13 PM
540iman's Avatar
540iman 540iman is offline
resident, old fart
Location: N.W. Indiana
 
Join Date: Sep 2008
Posts: 1,504
Mein Auto: 2002 540i sport
Get the re-fill cans that have pag oil already in them. The only additive you DO NOT WANT IS LEAK STOP of any kind!
Reply With Quote
  #24  
Old 06-07-2011, 12:12 PM
bmw_lover85 bmw_lover85 is offline
Officially Welcomed to the 'Fest
Location: Indiana
 
Join Date: Dec 2010
Posts: 178
Mein Auto: 97 528i manual.
Thank you for the replies. I will see what I can do and report back if my problem is solved.
Reply With Quote
  #25  
Old 07-08-2011, 01:34 PM
tspeed tspeed is offline
Officially Welcomed to the 'Fest
Location: N. California
 
Join Date: Oct 2007
Posts: 105
Mein Auto: 04/98 528
bmw lover85, anything to report regarding the noisy a/c compressor? Did you add any refrigerant and if so did the noise decrease or went away?
Mine just started clacking too and thinking about doing the same to buy some time.
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E39 (1997 - 2003)
Today's Posts Search
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



Forum Jump


All times are GMT -7. The time now is 11:20 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms