purplegrog

What kind of PSI should I be seeing on my manifold gauges on my high side? On a hot Texas summer day with around 100°F and 36% humidity, I am seeing 55 PSI on my low side and 225 PSI on my high side. Various charts I've found on the internet suggest the low side pressure is normal, but the high side should be more in the range of 315-325 PSI.

I've noticed lately the car seems to take longer to "blow cold" from a cold start, and often, especially when stationary the air coming from the vents will get humid and will not blow as cold.

What is a more likely scenario I'm looking at? an AC system needing additional refrigerant? bad compressor? bad radiator fan?

kajtek1

First testing variable output compressor is tricky as you have to kick it in max output.
That can be done when car is park under direct sun and after starting the engine you have few minutes when AC works at max.
225 psi = 15 bars. Good working pressure should go to 20 and above, while low side should drop to about 2 bars.
If what you measure was at climatronic set to max, your compressor is wear out.
But do another test on very hot day.
Testing is much easier if you have climatronic with REST button, what allows you to do it at 80 mph.
Just for that reason I replaced climatronic on our 2nd W211 that come with no REST button.

purplegrog

Is it as simple as swapping out the controller? I don't have a rest button and frankly it is one of the features I missed most going from the W210 to W211. my previous W211 didn't have a rest button either, but if I could buy a control module on ebay and swap it out to get the functionality, I would happily do so.

kajtek1

About 20 minutes and it is plug&play.
I bought 4-zone climatronic on ebay for $40
I don't care for REST function, but like to know what is happening on my cars.
To top it looks like W211 gauges are "dummy" gauges.
They don't show overheating till the coolant is already boiling, so climatronic will show actual value.

purplegrog

Looking through the owner's manual (link: https://www.mbusa.com/vcm/MB/Digital...550_e63amg.pdf , Page 214) for my model year, it looks like Units with a REST button are Canada Only. The US version has "Max cool." Does anyone know if swapping with the canadian interface will still provide the readings on a facelifted W211? Would swapping the interfaces provide me with the Rest functionality?

kajtek1

One of our US W211 has 4-zone climate and that is the model of climatronic I bought for our 2nd W211
http://www.ebay.com/itm/03-06-W211-M...JWxzwS&vxp=mtr

purplegrog

Right, but isn't that the pre-facelift W211? Did you put it in a post facelift model, and is it forwards compatible?

kajtek1

we have 2004 and 2008 models.
Pre and post lift. The interior seems the same.
The only issue I faced is the loudspeaker cover that took longer to find removing VIS

purplegrog

Thanks for the insight!