Got my AC working! - PeachParts Mercedes-Benz Forum

benfield4 · #1 08-02-2011, 05:20 PM

Thought I would share some good news!

Well I bit the bullet and decided to get the AC going in the 89 300SE. It was not functioning when I bought it and had not worked the whole time the previous owner had it for 5+ years. Last year I took it to a local indi MB shop and had him try to make it work. He was able to charge it but said that I had high preasure on the low side and probably an obstruction. So he evacuated it and I went without AC till the first of July this year. I got the following new parts:

Compressor (Denso Factory Remanufactured)
Expansion Block/Valve (the Eghoff from here)
Receiver/Dryer
High and Low preasure switches on R/D
Set of new O rings for all of the hoses.
New Aux electric fan (ACM brand)

Started by taking off the expansion valve, compressor and opening all the lines. Flushed the Evaporator, Condensor and all the lines (except the run with the muffler). I used the Napa DuraFlush II and got the most of the dirty flush fluid from the evaporator with a few bits of black stuff. A few aluminum shavings from the condensor. Flushed the Evap 6 times with the flow and against. Condensor 3 times and hoses 2 times. Buttoned it all back up with oil in the evap and new compressor and pulled a vaccum on the system without the Receiver/Dryer on it but the lines joined together with a hose. Held that vacuum for 4 hours using the pump. Installed the new receiver dryer and vacuumed that down for another 2. Crossed my fingers and took it back to the indi shop and had him charge it up. He added more oil to it while charging it with R12 and its now functioning great! Cools the car down nicely in 85 degree weather. Our summer has been unseasonably cool here so no 95 degree plus test yet. Over all I am happy with it and its very nice to have it work.

Over all it was not too bad getting the expansion valve off the W126. Its just tight. You can almost do it without crows foot wrenches but its hard to do. I used some chineese wrenches and the shape of them is wrong. You need a more rounded head instead of a traditional open end wrench shaped head. I took about 2 weeks to do the job with ordering a few more parts including a new belt. Took my time on it instead of rushing. If you have been putting this job off and can spend the money on I encourage you to do it yourself. This was my first AC job and while I did not charge (yes I chickened out) it I did most everything else and saved some $$ on labor. Did a lot of reading on the forum and would like to thank everyone that has contributed to the forum for the help!

crs82 · #2 08-02-2011, 09:12 PM

About how much did you pay in parts alone?

benfield4 · #3 08-03-2011, 12:49 AM

I bought some of the parts last year and some this year

Compressor (Denso Factory Remanufactured) $395
Expansion Block/Valve (the Eghoff from here) $22
Receiver/Dryer $50
High and Low preasure switches on $16
Temperature switch $18
Set of new O rings for all of the hoses. $17
New Aux electric fan (ACM brand) $90 ish
Mineral oil 4 - $6

3 Quarts of flush at $39 each

3 LBS of R12 at $60 per lbs. This is where I chickened out. Could have saved some $$ by getting certified and doing the charge myself. The shop sells the R12 for what they bought it for.

So its a bit of coin to get it going with the worst offenders being the pump and the R12. The old fan was making a racket while running so if yours is good then you can save there.

Hurts a bit while spending the $$ but with the dark brown interior and a hot day in the sun at the parking lot at work it beats a sweaty back after the commute home.

benfield4 · #4 08-03-2011, 12:56 AM

By the way. The compressor was my decision to replace. It showed no clear indication of being bad but since I was removing it to do the flush and it had not been used in so long I decided to replace it. Its a bit of a job to R and R the compressor but nothing like the expansion valve!

Hirnbeiss · #5 08-03-2011, 07:49 AM

Isn't the correct title "Got my Mojo Working"?

Also, you should finish your list of prices with:

"Arctic breeze in my face on a 95 degree day, priceless:"

crs82 · #6 08-03-2011, 10:45 AM

That's actually not that bad for a complete overhaul of the system. I know it stings in the wallet, but like Hirnbeiss says, "...priceless..."

benfield4 · #7 08-03-2011, 10:59 AM

LOL True on the Mojo and Arctic Breeze. I have not felt buyers remorse yet so it must be ok! Heck even mama (my wife) will ride in it now and even commented on how nice it was. She has not been a fan of the Benz purchase. I like the car even more now that it keeps me cool. The only thing that is not functional now is the cruise control. No plans at this time to resurect that. I mainly commute in the car and never use CC.