[W126 Coupe] A/C Not cooling

[Dick Spellman]

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 

> <mailto: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 

>> <mailto: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

>>     <mailto: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 <mailto: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

>>>         <mailto:mbcoupes-request at mbcoupes.com> wrote:

>>>

>>>>         Message: 6

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

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

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

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

>>>>         <mailto:mbcoupes at mbcoupes.com>>

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

>>>>         <mailto: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 <mailto: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!

>> W126 SEC Mailing List

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

>

>

> The MB Coupes Website!

> W126 SEC Mailing List

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



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