here is my dilemma, i live in palm springs and its like 120 degrees right now....and will remain that way until october. i recently (2 weeks ago) had some work done on my 1990 190E 2.6: r12 converted to r134a, brand new a/c compressor installed, receiver dries installed, new alternator, new idler pulley alt, new bearing bracket, new tensioner pulley, new belt, new idler pulley a/c. from my understanding, these mb models only have a/c in the center vents, but even though my a/c works, it doesnt seem cool enough. you know how some a/c if you put your hand to the vent it will damn near freeze your hand. well when i put it to my vent, its cool, but it is far from freezing my hand. if i had to guess, id say its only like 65 degrees, but the car never cools down and if i turn the a/c to max it will blow warm air ( my guess may be distorted a bit since its usually 120 here in palm springs). so my question is there anything to do to make it cooler like a normal a/c or am i just screwed? please advise, i have 90 day warranty for this?

Do a searsh for mono valves or duo valves depending on your set up. Also do a search for "warm air out of vents 1990 190E". Read, follow directions, if that doesn't work, search, read, follow directions....

__________________
If it ain't broke take it apart and find out why.

1983 300SD, 4 speed
1994 C280
1987 300TD wagon
1996 HD Road King

Ride in Peace Eric Peterson, Harley of Macon

Many folks reading your post, will blame the loss of cooling oomph on the conversion to 134. The R12, would've given better cooling.
If you must use 134, there are specially designed evaporators that are supposed to help.

----upon re-reading your post, you might want to check your fuses closely too.

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

(Is the horse dead ,Yet?)

1.Call ACKITS first thing Monday and order a Parallel Flow Condenser.
(You'll have to have some new lines made up ...the PFC's ports probably
will not match the location of the OE condenser.)


1a.Go buy an inexpensive dial type thermometer (less than $5.00 at a Kitchen
Supply Store),then you can stick it in the vents and actually know what temp
the A/C is putting out.

2.(Wait for It)...The only way you're gonna get 35 to 38 degree air out of the
vents with R-134 would be with a Parallel Flow Condenser (Now Larry D's got me scrambling
around the "Net" looking for "Special" Evaporators Also)which is 30% more
efficient at heat transfer than a regular Condenser.
You can get these Mercedes to the "Hang Meat inside the passenger compartment"
with R-134...BUT just changing out the Compressor and
"Converting" ain't gonna cut it.

The two different refrigerants are similar...but R-134 has smaller molecules
AND runs higher pressures AND does not have the heat transfer ratio that
R-12 does.So you have to make physical corrections to "Convert" successfully.

Attached Thumbnails

   

__________________
'84 300SD sold
124.128

Whoops! I posted after an entire day with a most energetic 4.5 year old boy - not only could I not remember "parallel flow", but I also swapped evaporator with condenser (even after looking at the word, trying to rack my brain why it didn't look "right".)

-Larry

__________________
It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

Thank you all

Before throwing more parts at it, I would want to know what the pressures are on the high and low sides. Quite possibly you have a restriction somewhere causing the loss of cooling performance. Also possible that you still have a leak somewhere and are low on refrigerant. Before you spend more money on repairs, you need a proper diagnosis.

I would also try freeze-12 or HC-12a instead of R134

a couple of things about 134..

i don't think it cools quite the same as freon.. i live in florida..

it cools the same as long as you are cruising above 1500 rpm...

stop and go city driving won't cut it..

i find parking out of sunlight is the biggest help.... also drive for a minute with the windows down...and get the inside temperature from 120 to 95..

__________________
1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

first,134 is only 70% as efficient as r12 so you have to replace hard parts to get the efficiency up.as suggested a new parralel flow condensor would be best BUT that will be expensive as a one off installation.almost as good is to remove your condensor plug the pipes and spray it down with mag wheel cleaner[acid]to remove the black paint and give you shiny tubes.this will increase efficiency by about 20%.seeing as condensing is the big downfall of134[when ambient goes above 93f]i would also wire your aux fan[s] to run at full speed whenever the compressor is on.good luck .

__________________
David S Poole
European Performance
Dallas, TX
4696880422

"Fortune favors the prepared mind"
1987 Mercedes Benz 420SEL
1988 Mercedes Benz 300TE (With new evaporator)
2000 Mercedes Benz C280
http://www.w108.org/gallery/albums/A...1159.thumb.jpg

<>

That makes a great difference, specially in stop and go traffic.

I don't know if the A/C vacuum valve arrangement is the same as the 300E, but if it is, the recirculation feature uses a dual diaphragm vacuum arrangement with two valves which either permits 100% or 80% recirculation. If the inner vacuum diaphragm on one of the recirc valves is leaking, you will only get 80% recirc air no matter what. The other 20% is hot, outside air. Also, I get cold air out of my side vents if A/C is demanded. The bad news is that to replace these recirc vacuum valves you have to remove the dash. The defrost valve, if defective, can be replaced by removing the glovebox to gain access.
You might want to have all the A/C vacuum valves checked. My '92 300E with 141,000 miles was recently checked by me and had a bad defrost valve and bad recirc valves for the 100% recirc feature. I ordered the valves and intend to replace them next week.
I know you have already spent a great deal of money on your A/C, but if the vacuum valves are bad, the A/C will not work to its full potential. The 300E has a total of six vacuum valves. Not sure what the 190E's setup is.