[W126 Coupe] A/C Not cooling

[mavris2 at gmail.com]

The other issue with the cooling system is if you have never cleaned the condenser that also plays a factor in performance. 
Jason 
Sent from my LG phone

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>

>> 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>

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

>>>

>>> Message: 6

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

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

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

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

>>> mbcoupes at mbcoupes.com>

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

>>> 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>

>>> jhodgman at gmail.com> wrote:

>>>

>>> ya'll running R134a??

>>>

>>>

>>>

>>>

>>> The MB Coupes Website!

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

>>>

>>

>>

>>

>>

>

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