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What I Have Done To Get Good A/C Cooling

Started by bolbol, 16 September 2008, 12:12 AM

bolbol

Hi board, its been a while since I was here, but have been very busy for all boards.

I think all know that I go to extreme measures to solve issues that are weak in the W116 design. One of those issues is the A/C AC. Even for those who claim that the A6 compressor set up is adequate, I will state that with an R12 its just OK but to get a better cooling her is what I did:

1. weather you are using an R12 or R134A, what I would change first is the inner AC/Heater Fan. Yes, I believe  the Fan is the weakest point in the system. It just does not blow enough air to cool the big Saloon of the W116. I have fitted a bigger fan from a W126 in place of the W116 fan, the result Major improvement. Its better to get more air at 12C central vent than 8C with not enough air flow.

2. I have replaced my A6 troublesome compressor with a 10P17C Neppo compressor. NOW pay attention, if  your A6 compressor is running fine then you will get better cooling by upgrading the blower fanonly . if not and you don't want to replace your compressor with an A6, then the second best alternative is to go to a rec yard find a 89-91 560SE, SEL, C and then you can get the compressor and mounting bracket, YES , The mounting bracket will fit our V8 block,Walla.
Note: 10p17c can be found on Accuras, Toyota's, VW, Audi of that time also but then you will have to buy or custom make a bracket.

3. What I have done, but I will not recommend is: I have changed my original condenser with a parallel flow condenser and two auxiliary fans that came off an S500 W140. I truly believe that our condensers are more than adequate for R12 and R134A, don't fall for the hype of parallel flow condenser, "there are so many reasons why I am sure of this", just find a way to install either a bigger Aux. fan or two fan set up which I have done.

There are so many things I could state in this post, but I will wait for your questions.

Best regards
bolbol

WGB

Is the 126 fan a straight fit or does it need a change of blades/motor/mounting panel.

Bill

scraf

While doing an engine transplant I just removed the AirCo from my 450 SEL, it wasn't working, and was empty as it goes. Three reasons.....

#1 I live in the Netherlands, so it doesn't really get hot enough to warrant it. Happy with working windows and an open roof.
#2 Quite a good chance I will get better fuel economy, and maybe better performance without the engine having to turn the pump
#3 When a guy I knew took a look at it ( a chap from Cuba who's trade was once automotive air conditioning ) he told me that the system I had was illegal in every country in the world, due to emmissions, I guess.

bolbol

WGB, you will need to custom fit the new motor to the existing motor housing, not a hard job at all.

bolbol

TJ 450

Hi scraf,

There's no chance that the system is illegal at all, however charging with R12 is illegal in a lot of countries. R12, or Freon contains CFC's, allegedly responsible for breaking down the ozone layer.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

pez

I'll add my two cents....
while not totally related to good a/c function, this relates to both a/c and general engine cooling issues:

I have added a simple on/off switch beneath my ignition barrell [mounted on the knee bolster beneath the dash] to control my aux fax.  The fan will still kick on at 100C [which I think is just too damn high...but that's what the engineers intended], although I can manually force it to turn on anytime I want to.  This was accomplishes by simply routing a [negative] wire to the switch from the coolant temp sensor, and then routing it back to engine block for ground.  When the switch is thrown, it completes the negative ground loop, which is all it takes to cause the fan to run.

I will run the aux fax when the a/c is on and I am in traffic [not needed for driving steady over about 35mph], and I can report that the additional airflow past the condensor does make the a/c much cooler.  As for engine cooling, I can't really say, becuase my car runs at a steady 85C most of the time, except for the hottest days [over 40C ambient] in traffic, it will run up to 90C.

It took all of 30 minutes to wire the switch in a professional manner. I highly recommend it.