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
  #466  
Old 08-31-2018, 09:32 AM
WTB: 94/95 E320 Wagon
 
Join Date: Oct 2007
Location: Charleston SC
Posts: 2,479
Yes that helps. I've been thinking about the recirc flap and how well that is doing its job. The vacuum pod for the center vent has failed on this car, I finally got around to hacking that (wired the door open) so I've got good airflow over the evap coil. How far behind are the other flap vacuum pods from failing? That is to be determined. I need to break out the HVAC section of the FSM and go through all the test procedures to make sure all the senors and the other vacuum pods are still doing their thing.

My vent temperatures only climb about 5 degrees at idle vs. moving, but the longer I sit and idle, the higher they go above that initial 5 deg.
__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~380k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 379k miles
'73 Balboa 20 "Sanctification"
Charleston SC
Reply With Quote
  #467  
Old 08-31-2018, 10:27 AM
WTB: 94/95 E320 Wagon
 
Join Date: Oct 2007
Location: Charleston SC
Posts: 2,479
Here's a nice video explaining how to do some basic system diagnosis using temperature readings.

https://youtu.be/wF37ihNBXq8
__________________
Respectfully,
/s/
M. Dillon
'87 124.193 (300TD) "White Whale", ~380k miles, 3.5l IP fitted
'95 124.131 (E300) "Sapphire", 379k miles
'73 Balboa 20 "Sanctification"
Charleston SC
Reply With Quote
  #468  
Old 08-31-2018, 10:30 AM
Diseasel300's Avatar
Registered User
 
Join Date: May 2016
Location: Texas Hill Country
Posts: 3,993
Quote:
Originally Posted by Maxbumpo View Post
My vent temperatures only climb about 5 degrees at idle vs. moving, but the longer I sit and idle, the higher they go above that initial 5 deg.
That kind of behavior is to be expected, especially on a hot day, and double especially if the cabin hasn't completely pulled down. Remember that an A/C does not "make cold", it "removes heat". When you're moving, the compressor RPM is elevated which increases the capacity of the system due to mass flow of refrigerant. The engine fan blows harder, and the ram air effect of the car moving through the air dramatically increases the amount of heat that the condenser can reject. Airflow over the condenser is only part of the equation, the other part is the amount of refrigerant flowing through the system at any given time.

Idle is the lowest capacity that the system has. If the heat gain of the vehicle is more than it can handle, the vent temp will rise. Once the cabin pulls down completely (10-15 mins at least on a hot day), the vent rise will be significantly less at idle.

Window tint helps a lot too. Both the SDL and the Honda are dark colors (Midnight blue and black, respectively). The SDL has clear windows, the Honda has tinted windows. Even with the windows and sunroof cracked and a reflector in the windshield, it's not uncommon for the SDL to be 145-150˚ in the cabin at the end of the day after being parked in the sun. The Honda will easily be 15-20˚ cooler from the tint blocking out all that radiant heat.
__________________
'11 Honda Accord EX - "The Daily" 64K
'83 500SL Euro - "The Money Pit" 116K
'86 300SDL - "The Diseasel" 186K
The Diseasel Thread - Everything You Didn't Know You Wanted To Know
Reply With Quote
  #469  
Old 08-31-2018, 10:52 AM
Diseasel300's Avatar
Registered User
 
Join Date: May 2016
Location: Texas Hill Country
Posts: 3,993
Quote:
Originally Posted by Maxbumpo View Post
Here's a nice video explaining how to do some basic system diagnosis using temperature readings.

https://youtu.be/wF37ihNBXq8
That's a very good video explaining how the temperatures relate to efficiency of the system. MVAC is very similar to HVAC, but often operates at much lower superheat settings and much larger ∆T.

It's important to note when testing MVAC systems that the doors/windows need to be open so that the system is cooling ambient air, not recirculating the cabin air.

As a comparison to that video using my own car earlier this summer:

With an ambient temp of 102˚F, I had a difference of 41˚ across the condenser (139˚ discharge temp), 40˚ across the evaporator (62˚ discharge temp), and a superheat of around 4˚ at the return line to the compressor (65-66˚ line temp). I took all those measurements for a friend trying to get the charge right on their own car with an unknown quantity of refrigerant already in the system, but suspected to be low. I don't have a fancy CPS tester like the video creator did, I used a pair of Type K thermocouples attached to BK meters at work.
__________________
'11 Honda Accord EX - "The Daily" 64K
'83 500SL Euro - "The Money Pit" 116K
'86 300SDL - "The Diseasel" 186K
The Diseasel Thread - Everything You Didn't Know You Wanted To Know
Reply With Quote
  #470  
Old 09-03-2018, 12:41 PM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 3,648
Quote:
Originally Posted by Yak View Post

The A/C lines and fittings, even though they're on an otherwise metric car, are SAE sized. Having the right tools is also very important.

You really cannot assume anything when you're working on the A/C.

Iím primarily concerned about the W123, but other vehicles are relevant in this thread.

Is this everybodysí observation on all Daimler vehicles of general interest here (115/123/124/126) that may have run R12?

I will have my system open and therefore will plan to replace all o-rings with new green ones and the appropriate nylog for R-12. But want to be double sure that Iím using the right sized ones. I assume the fittings and o-ring sizes are associated with each other?
__________________
Own:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)
1998 Chevrolet S-10 ZR2 (62K)
2011 BMW 135i cv (14k)
2014 Honda Odyssey (6k)
2015 Honda Accord Hybrid (5k)
Had:
2008 VW Rabbit (70k)
2004 SAAB 9-3 (83k)
1991 BMW 318i (183K)
1983 300D (228K) (wrecked by at-fault uninsured driver)
1985 300D (233K) (now in FL)
1994 Acura Integra (188k) (Rusted out)
1992 Toyota 4Runner (72k) (Rusted out)
1990 Daihatsu Rocky (??) (No parts)
Reply With Quote
  #471  
Old 09-03-2018, 12:45 PM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 3,648
Quote:
Originally Posted by leathermang View Post

The more usual way to check for leaks is to pressurize with Nitrogen and four ounces of R22 ( which the EPA allows you to vent legally )..
This would negate any potential oil compatibility issues .
And would usually cost less than having the R134a evacuated by a pro with the proper equipment charging for their time...
Generally I spare no expense to do a job right, but just thinking out loud... I have a Co2 extinguisher, a regulator and a good deal of r134a.

Would the pressurized leak test be viable with co2 and r134?

My understanding is that this would be done statically without the system operating, so oil miscibility and flow would not be a concern.

Just saves buying stuff Iíll hopefully never use again, and buying r22 (for which I have a license so I can procure, just like r12) merely to vent.

Thanks!!
__________________
Own:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)
1998 Chevrolet S-10 ZR2 (62K)
2011 BMW 135i cv (14k)
2014 Honda Odyssey (6k)
2015 Honda Accord Hybrid (5k)
Had:
2008 VW Rabbit (70k)
2004 SAAB 9-3 (83k)
1991 BMW 318i (183K)
1983 300D (228K) (wrecked by at-fault uninsured driver)
1985 300D (233K) (now in FL)
1994 Acura Integra (188k) (Rusted out)
1992 Toyota 4Runner (72k) (Rusted out)
1990 Daihatsu Rocky (??) (No parts)
Reply With Quote
  #472  
Old 09-03-2018, 05:49 PM
ROLLGUY's Avatar
ROLLGUY
 
Join Date: Oct 2007
Posts: 5,880
Quote:
Originally Posted by JHZR2 View Post
Generally I spare no expense to do a job right, but just thinking out loud... I have a Co2 extinguisher, a regulator and a good deal of r134a.

Would the pressurized leak test be viable with co2 and r134?

My understanding is that this would be done statically without the system operating, so oil miscibility and flow would not be a concern.

Just saves buying stuff Iíll hopefully never use again, and buying r22 (for which I have a license so I can procure, just like r12) merely to vent.

Thanks!!
It is against the law to vent r134a, so I would just use the cO2 at around 250 psi to test for leaks.

Concerning O rings (above post), there are #6, #8, #10, and #12 used in these systems. Cars with the Denso compressor have a special manifold seal. Other than that, standard size O rings are used everywhere else.
Reply With Quote
  #473  
Old 09-03-2018, 08:11 PM
Diseasel300's Avatar
Registered User
 
Join Date: May 2016
Location: Texas Hill Country
Posts: 3,993
Quote:
Originally Posted by ROLLGUY View Post
Cars with the Denso compressor have a special manifold seal. Other than that, standard size O rings are used everywhere else.
Possibly later models. My '86 SDL has the factory manifold on it and uses standard O-rings.
__________________
'11 Honda Accord EX - "The Daily" 64K
'83 500SL Euro - "The Money Pit" 116K
'86 300SDL - "The Diseasel" 186K
The Diseasel Thread - Everything You Didn't Know You Wanted To Know
Reply With Quote
  #474  
Old 09-03-2018, 11:58 PM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 3,648
Quote:
Originally Posted by ROLLGUY View Post
It is against the law to vent r134a, so I would just use the cO2 at around 250 psi to test for leaks.

Concerning O rings (above post), there are #6, #8, #10, and #12 used in these systems. Cars with the Denso compressor have a special manifold seal. Other than that, standard size O rings are used everywhere else.

Thanks very much!

It seems to be very difficult to find any set that has #6 size o rings. Do you recall where this size is used?

Thanks again!!
__________________
Own:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)
1998 Chevrolet S-10 ZR2 (62K)
2011 BMW 135i cv (14k)
2014 Honda Odyssey (6k)
2015 Honda Accord Hybrid (5k)
Had:
2008 VW Rabbit (70k)
2004 SAAB 9-3 (83k)
1991 BMW 318i (183K)
1983 300D (228K) (wrecked by at-fault uninsured driver)
1985 300D (233K) (now in FL)
1994 Acura Integra (188k) (Rusted out)
1992 Toyota 4Runner (72k) (Rusted out)
1990 Daihatsu Rocky (??) (No parts)
Reply With Quote
  #475  
Old 09-04-2018, 12:05 AM
ROLLGUY's Avatar
ROLLGUY
 
Join Date: Oct 2007
Posts: 5,880
Quote:
Originally Posted by JHZR2 View Post
Thanks very much!

It seems to be very difficult to find any set that has #6 size o rings. Do you recall where this size is used?

Thanks again!!
On a W123 the drier has #6, Condenser a #6 & #10, and #12's for the suction line. The short hose from the hard line mounted on the motor mount arm is either a #8 or #10. The TXV uses #6, #10 & #8 (I may be wrong on the TXV, someone correct if needed). Either way, a complete HBNR O ring assortment is available from Harbor Freight. It has all the sizes needed and more.
Reply With Quote
  #476  
Old 09-04-2018, 11:36 AM
Registered User
 
Join Date: Nov 2010
Location: TX
Posts: 3,380
Quote:
Originally Posted by JHZR2 View Post
Thanks very much!

It seems to be very difficult to find any set that has #6 size o rings. Do you recall where this size is used?

Thanks again!!
you can buy a correct vehicle specific O ring set from autozone etc, they are branded as santech and come in little baggies for about 5 dollars. They have all the rings including any special manifold seals.

I use these seal sets now on every car I do, no more hunting for correct sizes and the rings I get have an expiry date so I always get fresh rings for a fresh job.
__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)
Reply With Quote
  #477  
Old 09-04-2018, 03:29 PM
JHZR2's Avatar
Registered User
 
Join Date: Jan 2002
Location: New Jersey
Posts: 3,648
Quote:
Originally Posted by ROLLGUY View Post
On a W123 the drier has #6, Condenser a #6 & #10, and #12's for the suction line. The short hose from the hard line mounted on the motor mount arm is either a #8 or #10. The TXV uses #6, #10 & #8 (I may be wrong on the TXV, someone correct if needed). Either way, a complete HBNR O ring assortment is available from Harbor Freight. It has all the sizes needed and more.
I can’t find an HNBR set that has #6. The other sizes, yes. Can get standard nitrile and viton sets there that have #6 size.

Maybe HF on your coast carries different models than mine?
Thanks!
__________________
Own:
1981 240D (73K)
1982 300CD (162k)
1991 350SD (113k)
1998 Chevrolet S-10 ZR2 (62K)
2011 BMW 135i cv (14k)
2014 Honda Odyssey (6k)
2015 Honda Accord Hybrid (5k)
Had:
2008 VW Rabbit (70k)
2004 SAAB 9-3 (83k)
1991 BMW 318i (183K)
1983 300D (228K) (wrecked by at-fault uninsured driver)
1985 300D (233K) (now in FL)
1994 Acura Integra (188k) (Rusted out)
1992 Toyota 4Runner (72k) (Rusted out)
1990 Daihatsu Rocky (??) (No parts)
Reply With Quote
  #478  
Old 09-04-2018, 10:05 PM
ROLLGUY's Avatar
ROLLGUY
 
Join Date: Oct 2007
Posts: 5,880
Quote:
Originally Posted by JHZR2 View Post
I canít find an HNBR set that has #6. The other sizes, yes. Can get standard nitrile and viton sets there that have #6 size.

Maybe HF on your coast carries different models than mine?
Thanks!
That is odd. I am sure the set available in your store is the same one in mine. I used up all the #6 rings in the kit, and bought 100 of them to re-stock my kit. I am sure Amazon will have a kit that will have all you need. Try them......Rich
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 10:46 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