A/C R134a pressures too high. I'm lost. Ideas? - Page 4 - PeachParts Mercedes-Benz Forum

lorainfurniture · #46 07-10-2012, 02:21 PM

Having just complete a w124 evap+ vacuum pod job, I can say that it is not as bad as people make it out to be. I took a roll of painters tape, and marked all of the wires that I disconnected.

It does take time, in fact, I started a couple of weeks ago, and am still not 100% finished. I have been waiting fo a new condensor to arrive.

The hardest part is just starting the job.

ps2cho · #47 07-10-2012, 04:57 PM

I did a complete pod replacement along with the evap on my 260E 2 years ago so I'm familiar with what needs to be done.

In fact, my dash is cracked, so its on the list to replace it anyway. I don't want to touch the evaporator this time though. The evaporator has no signs of leaking, so I see no reason to touch it. I remember I got the dash off in about 2hrs first time around.

From --> http://w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/Climate/83-620.pdf

1: Recirculation Air Flap <-- dead
2: Recirculation Air Flap <-- dead
3: Footwell Flaps <-- GOOD (and I know they work anyway...)
4: Center Nozzle Flap <-- almost dead?
5: Defroster <-- GOOD
6: Diverter <-- dead
7: Defroster <-- dead

So yep, looks like I am getting hot air into the cabin at all times right?

lorainfurniture · #48 07-10-2012, 05:27 PM

Interesting enough, I am dealing with a chebby that has somewat of a similar symptom. It has a dead condensor fan, making the pressures spike in to the stratosphere.

Is your shroud in place? I bet it is, but worth asking.

You cant add much freon because your car cannot disperse the heat quick enough resulting in higher pressures. Also, I read somewhere in this thread that you put the can in chilled water? The can will tolerate a significant amout of heat. I usually wedge it near the radiator hose. The warmer the gas=more gas boiling=more pressure.

Having working recirc will help with cooling the cabin while driving. Do you have your windows tinted?

ps2cho · #49 07-10-2012, 06:18 PM

Just got her retinted 4 months ago. 30% front 15% rear and that helped...I think realistically I just need a complete refresh f almost every component

...but I'll start with the pods, duovalve then move onto compressor/condenser and R12.

Air&Road · #50 07-11-2012, 08:21 AM

Quote:

Originally Posted by ps2cho

I did a complete pod replacement along with the evap on my 260E 2 years ago so I'm familiar with what needs to be done.

In fact, my dash is cracked, so its on the list to replace it anyway. I don't want to touch the evaporator this time though. The evaporator has no signs of leaking, so I see no reason to touch it. I remember I got the dash off in about 2hrs first time around.

From --> http://w124-zone.com/downloads/MB%20...ate/83-620.pdf

1: Recirculation Air Flap <-- dead
2: Recirculation Air Flap <-- dead
3: Footwell Flaps <-- GOOD (and I know they work anyway...)
4: Center Nozzle Flap <-- almost dead?
5: Defroster <-- GOOD
6: Diverter <-- dead
7: Defroster <-- dead

So yep, looks like I am getting hot air into the cabin at all times right?

A very wise man leaving the evaporator be!

Air&Road · #51 07-11-2012, 08:22 AM

Quote:

Originally Posted by ps2cho

Just got her retinted 4 months ago. 30% front 15% rear and that helped...I think realistically I just need a complete refresh f almost every component

...but I'll start with the pods, duovalve then move onto compressor/condenser and R12.

You are wise for waiting to do anything more until after fixing the recirc pod. I expect that it is a big part of the problem you're sweating with, pun intended.

ps2cho · #52 07-11-2012, 03:45 PM

These pods are expensive these days boy its up $50 from 2 years ago....Oh well!
Sourcing a new dashboard first since mine has cracks in it. Once I get a new dash in, will do the "podectomy" right away.

gabzor · #53 07-12-2012, 11:35 AM

didn't know you can test those pods!!
sweeet.. looks like my weekends are already planned.. well more than homework

it applies for the m104 AC as well right?

ps2cho · #54 07-12-2012, 12:12 PM

Yep, all the same.

Just bought this dash -- should have it in a few weeks

Should be a very nice upgrade and the wood looks great.

ps2cho · #55 07-12-2012, 12:50 PM

http://w124-zone.com/downloads/MB%20CD/W124/w124CD1/Program/Climate/83-601.pdf#page=1

Found this PDF dug in deep in the climate control section -- its a GOLDMINE!
It shows EXACTLY under which setting WHERE the air is SUPPOSED to come out.

For regular A/C setting with no footwell air....the defroster vents are supposed to be closed -- well I am getting huge amounts of air coming out of them. I bet what's happening is that I am losing 30% or more of air volume because its coming out of the defrost vents instead of at the passengers. Plus, now that I can see my center nozzle flap is barely holding vacuum, its probably not opening all the way either so I am losing air volume there too.

ps2cho · #56 07-12-2012, 04:13 PM

New duovalve in!

I checked operation, and its definitely working as its supposed to. I disconnected the heater core line with engine running and A/C on LOW -- no coolant was flowing out of the unit at all. That issue is now off the list

I then turned on the defroster and I could feel coolant flowing through.
Will report back if it makes any difference right now even with the vacuum pods not working.

platt-deutsch · #57 07-13-2012, 01:21 PM

To see if the duovalve is screwing up , just pinch off the hoses to it.. if the evaporator outlet temp drops then the duovalve is not shutting off complely..

ps2cho · #58 07-19-2012, 03:56 PM

Look what just arrived right now!

Looks like I am gonna be busy today!
1pm right now...let's see if I can get it all the new pods installed by todays end.
Ready...set...go!...well lunch first

ps2cho · #59 07-19-2012, 05:29 PM

Dash off! So looks like it took just over an hour minus lunch time

Dang I am quick at this now

Going to take it slow with the pod replacement and I am also going to spend some time cleaning all the dust off everything too...so far so good nothings broke yet.

ps2cho · #60 07-19-2012, 07:30 PM

Pods done and retested with MityVac to ensure no mistakes or anything. Just reposting so I keep track of the actual time taken on this one.

The pods are a little fiddly...2hrs to do them it seems.
Putting new dash back in I figure 2hrs left.

Oh and the new dash is about a 1/3rd darker than my old one...the Arizona heat really hits the color hard. The fading is quite noticeable side-by-side!

As always I have a ton of photos for a pretty decent step-by-step that I will post later once I am done.