AC troubleshooting help, please? - Page 2 - PeachParts Mercedes-Benz Forum

Demothen · #16 06-05-2016, 10:11 PM

Thanks! Just to confirm since my phone can't open the online FSM, I need the blue Nylog, right? That seems to be universal according to thr review you posted.

leathermang · #17 06-05-2016, 10:56 PM

You are using 134a .....blue....

Nylog Blue

FE240D · #18 06-05-2016, 11:24 PM

My '82 240D ac --with r12-- chugs along nicely with an r4 compressor going on 34 years now, they can't be that bad...

May want to clean the evap while you are at it, the system lacks filtration so gets dirty in time & air doesn't move over the cooling coils nicely. The blower motor comes out easy peasy and you can squirt some foamy evap cleaner in there -even home depot carries it. Also used a pump up garden sprayer with water, reach in with the plastic wand and spray away. Make sure your ac drain is a-ok before cleaning.

leathermang · #19 06-05-2016, 11:35 PM

I already challenged him to clean the evaporator...
and he claims he already has...
it can make all the difference...
as most people who do start to clean it will find they are the very first to do that in the life of the car....

Demothen · #20 06-05-2016, 11:38 PM

Yup. I cleaned mine while I had the dash out. Though I wasn't the first one to pull the dash, and I suspect that a previous owner had changed it, since my evaporator was surprisingly clean.

leathermang · #21 06-05-2016, 11:45 PM

Quote:

Originally Posted by funola

The temp switch comes on at 52C 125F IIRC. You could test it in warm water / thermometer and an ohmmeter to make sure it is working. Did you feel the dryer if it was getting warm? If you have the manifold gauge set, why not diy? You can rent a vac pump from Autozone. That's what I just did to charge my 85 300D with R152a Dustoff and it is colder than R134a. Time will tell if it is longer lasting than 134a, which does not last in mine and AC performance gets weaker with time (months). This is with the original non barrier hoses.

It is not legal to have retrofitted that 154a into your car with out upgrading to the barrier hoses... among other things....

It makes no difference if it is colder as long as the refrigerant keeps your car cold as adjusted by the ' pilot ' ( YOU ) controlled switch.

HERE IS WHAT is really important.... if you have an R4 compressor... it has NO OIL RESERVOIR ... Thus THE ONLY LUBRICATION YOUR R4 GETS IS THE OIL WHICH IS CARRIED BY THE REFRIGERANT....

So the " OIL miscibility " Is a critical factor for longevity of your system... the ability of your particular refrigerant to dissolve and carry the proper oil to your compressor makes all the difference when dealing with an R4....

BillGrissom · #22 06-06-2016, 02:11 AM

You should stop pining for a Sanden. I put one in my 1985 and it hasn't materially improved my life, nor the AC. The R4 in my 1984 works about as well. People say a parallel-flow condenser (of same area) is 30% more efficient. I haven't tried.

Both cars cool marginally when idling long at a stop light and it is hot outside. But, I noticed that was true in our 2002 T&C on a current trip when we were stuck in slow LA traffic on a 99 F day (unusually hot for them, normal in Sacramento). Once moving 30 mph, it cooled well. In that case, you are limited by physics. If your AC system can reduce the temperature by 60 F, that is fine on a 90 F day (hot on East Coast) since you get 30 F air out the vents. But, on a 110 F day in CA, you get 50 F from the vents, which isn't enough to fight the outside heat plus sun, so is simply "better than nothing". We resort to wet towels, and tinted windows are de rigur here.