[W126 Coupe] A/C Not cooling

[David Zatz]

Hello,
I have a 1987 560 SEC with 94,000 miles.
I had the AC converted to R134A a year ago. At the time , I also needed a
new compressor and Blower and  Blower control. The Ac System was thoroughly
cleaned , several times and refilled with R134A. The CC system works
perfectly and blows Ice cold in 100 deg heat, even at idle. You may simply
need a new compressor. Look for Mitsubishi Reman compressors. They are
usually brand new units. I paid $340- for mine.
Best wishes.
Tootsch

On Mon, Aug 15, 2011 at 12:19 PM, Dick Spellman <dick.spellman at gmail.com>wrote:


>  Any leak in the vacuum system can reduce the vacuum reservoir storage

> capacity used to manage your ACC vacuum switching valve and attached vacuum

> pods.

>

> -\Dick

>

>

> On 8/15/2011 2:47 PM, Yousef wrote:

>

> Its overall flow thats effected .. Could it be a vaccum leak from else

> where .. The inst cluster has loose hose to the eco gauge havent bother do

> it yet ..

>

> Sent from my iPhone

>

> On Aug 15, 2011, at 8:55 PM, Michael Ramay <mike.ramay at gmail.com> wrote:

>

>  Is the air flow down overall or just out of a set of vents? I've had to

> replace the vacuum module that controls the center vents on my SEL and SEC

> this year. Several folks have had the blower fan slow down from being gummed

> up with 20-25 year old lubrication.

>

> On Mon, Aug 15, 2011 at 9:43 AM, Yousef <usef4188 at gmail.com> wrote:

>

>>  I've noticed something on my SEC that sometimes airflow becomes somewhat

>> restricted .. It's more noticed on my W124.. When it's about shift from 2nd

>> to 3rd gear .. Again it's as if a vent is closed and the air is restricted

>> .. Cooling isn't affected .. Any ideas?

>>

>>  Yousef

>> Sent from my iPad

>>

>> On Aug 14, 2011, at 11:06 PM, Michael Ramay <mike.ramay at gmail.com> wrote:

>>

>>  Excellent discussions by Gary and Dick!!

>>

>> I took the AC system apart on my 560SEC, replaced all o-rings, flushed it,

>> new synthetic lubricant, and then filled it with propane (R290). That one

>> gives me 39F air out of the vents on a 105F Las Vegas day. It does not cool

>> that well sitting still, but it's acceptable. Any movement in traffic and it

>> cools right back down to 45F to 50F air.

>>

>> My 560SEL had been converted to R134 and as Gary states, it doesn't cool

>> as well as the SEC. That said, I put a dual electric fan setup on the

>> radiator in place of the engine driven fan (with a new 140-amp alternator to

>> handle that extra electrical draw) and that made a BIG difference in the

>> cooling. That car cools well sitting still and very good while moving. That

>> said, this winter I'm going to replace all o-rings, flush the system, and

>> change it back to R12 fittings and a propane fill.

>>

>> Mike

>> In HOT Las Vegas

>>

>> On Sun, Aug 14, 2011 at 10:39 AM, Gerry Van Zandt <gerryvz at me.com> wrote:

>>

>>>  If your A/C system was just the stock R12 system that was converted

>>> over to R-134a, it will NEVER cool more than about 60% as well as the R12

>>> system did UNLESS (as Dick explained) key components of the system are

>>> changed over to those that are optimized to work with R-134a.  R-134a

>>> requires a different set of parameters to work at its best and this is just

>>> not possible with a stock R12 system that has been emptied, new fittings

>>> installed, and filled with R-134a and compatible oil.

>>>

>>>  Dick did it right as he explained it, and thus is getting excellent

>>> results.  On the other hand, I had my system on my 1989 560SEC converted to

>>> 134a about 2001.  When I lived in Portland Oregon, where the temps rarely

>>> get above 85F in the summer, the 134a system (with its reduced capacity)

>>> worked just fine as long as the refrigerant level was up to the correct

>>> level.  However, since moving to Houston 3 years ago, I've found that my

>>> 134a system is pretty miserable in the summer heat.

>>>

>>>  My system is in tip-top condition (no major leaks, and all key

>>> components in good operating condition, though they are the stock R12

>>> components) and it only works decently when the car is moving in traffic.

>>>  Over long interstate trips (say from driving from Houston to Dallas) at

>>> high speeds it works quite well.  Never ice cold but will get the car down

>>> to a very comfortable/cool temperature.

>>>

>>>  I find the same thing as well -- below temps of about 80-85F outside,

>>> the converted system actually works quite well.

>>>

>>>  However in stop and go traffic, it's miserable and pretty much just

>>> blows warm air after a minute or so of being stopped.  I'm actually

>>> preparing to change my system BACK to R12 this winter -- my home A/C guy

>>> just sold me a left-over tank of about 15 pounds of R12 (for $50) that he's

>>> had sitting around for the past 15 years and not using.  I'll have my indy

>>> shop test my system for leaks, replace any components that need it, and have

>>> the R-134a removed & then the system cleaned out several times with solvent,

>>> R-134a fittings removed, and having new oil and R12 introduced back into the

>>> system.  Not an easy retrofit, but I can't handle another summer of only

>>> mediocre cooling.  My 1987 560SL (still on R12) is excellent in all

>>> conditions.

>>>

>>>  The bottom line is that you'll never get good efficiency from an R-134a

>>> conversion (from an R12 system) unless key components are replaced.  Systems

>>> designed specfically for R-134a (such as that on my 1994 E500 W124) work

>>> very very well (though still not quite as good as an R12 system, IMHO).

>>>  It's 96F outside and I just got home from downtown Houston (30 miles away)

>>> and was nice and chilly in my E500 all the way up I-45.

>>>

>>>  It's a serious consideration for those with R12 systems that have been

>>> converted to R-134a, to change them back now that the price of R12 has come

>>> WAY WAY down and the price of R-134a has gone up.  The difference in

>>> efficiency is truly worth making it worth considering.

>>>

>>>  My two cents.

>>>

>>>  Cheers,

>>> Gerry

>>>

>>>

>>>

>>>

>>>  On Aug 14, 2011, at 11:15 AM, mbcoupes-request at mbcoupes.com wrote:

>>>

>>> Message: 6

>>> Date: Sun, 14 Aug 2011 08:22:36 +0400

>>> From: Yousef <usef4188 at gmail.com>

>>> Subject: Re: [W126 Coupe] A/C Not cooling

>>> To: Mercedes Coupes Mailing Lists <mbcoupes at mbcoupes.com>

>>> Message-ID: <A5B63E26-49EA-408A-9634-0A612B4719A2 at gmail.com>

>>>

>>> Content-Type: text/plain; charset="us-ascii"

>>>

>>>  Yup runnin at 134a..

>>>

>>> Sent from my iPhone

>>>

>>> On Aug 14, 2011, at 2:00 AM, Jonathan Hodgman <jhodgman at gmail.com>

>>> wrote:

>>>

>>> ya'll running R134a??

>>>

>>>

>>>

>>>

>>> The MB Coupes Website!

>>> W126 SEC Mailing List

>>> Postings remain property of MB Coupes, L.L.C.

>>>

>>

>>

>>

>>

>    The MB Coupes Website!

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>

>

>

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> Postings remain property of MB Coupes, L.L.C.

>

>

>

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-- 
David Zatz
310-940-6457
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