What is john woods saying? I don't have time to watch 40minute videos.

John Woods is saying he learned the trick from his older Mercedes mechanic mentor. By using the newer switch it allows for more efficient cooling under the hood.

__________________
85 300TD (169K)

ok... BUT HOW???? What does this switch do?

The switch triggers the auxiliary fan to come on sooner rather than later thus helping the diesel engine from getting hotter than it should with the AC on. This switch which is from another Mercedes gives the auxiliary fan a heads start at reducing under the hood temps.

__________________
85 300TD (169K)

Please dont use vacuum for leak testing...
This is a mobile system with permiable rubber lines and a weep hole designed in on the compressor...

Leak test with a dry gas. Co2, argon, nitrogen or helium.
Vacuum out the gas, and charge quickly.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Greyish powder is residue from a failed compressor.
Keep flushing...

Yes, if you disconnect the small line from the bottom of the condenser coil, and route it into a liquid line filter, you can get additional cleaning of the refrigerant leaving the condenser coil.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Folks - thanks for everyone's input, I appreciate it.
I flushed everything several more times, and got it all very clean. Put it all together, added the proper oil, and vacuumed it for 7 hours.

I then charged it, and I am getting good vent temperatures and pressures.
However, my brand new AC Delco compressor is making a loud "shhhhhhh" noise regardless if the clutch is activated or not.
Perhaps it's a pulley bearing? Maybe the belt is slipping? It's not chirping or squeaking though. Belt tension felt correct to me, but I still need to play with that.

Just wondering if anyone else experienced something like this. It's not the typical marbles in a can noise that these compressors can make. Rather a constant loud hiss/whoosh noise, but no leaks or refrigerant issues.

Thanks!

Remember Gütentight is the new tight!
What brand belt is on the compressor?


Check out post #15 from this thread:
How Tight should the AC Compressor Belt be?

__________________
85 300TD (169K)

Thanks Toran, how tight did you end up making your belt then? I have heard from other folks that these ac belts need to be “excessively” tight

Tight, as in Gütentight!
LOL

I loosened the three 19mm compressor bolts and began tightening the 10mm compressor adjustment screw. The belt was tight as in very little deflection. Tightened the 19mm compressor belts and I was on my way to the center dash mod.

In terms of the belt it needs to be Gütentight!, if not than it sounds like Gute nacht to the compressor.

__________________
85 300TD (169K)

Okay, you've got my undivided attention, I'll watch this thread 'till it dies .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

I'm glad to be of service Nate!

Update: this noise does sound to me like a dry bearing. Happens if clutch is engaged or not. What's odd is that it comes and goes. Upon startup, it's quiet, then the noise starts 5-10 minutes later, then if I shut down the car and re-start, it will quiet down again. It's weird!

I tried adjusting belt tension with no luck.

Took a video of the noise, listen for the "shhhhhh" in this video. My old worn compressor did not make this noise.

https://www.youtube.com/watch?v=LaJkmsN_mLw

I don't know what to make of that .

Your idle speed sounds odd, like it's surging .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Kind of does sound like bearing noise. Do you remember spinning the pulley by hand? How did it feel?