I have conquered w124 Air conditioning. Now kneel. - PeachParts Mercedes-Benz Forum

lorainfurniture · #1 07-17-2012, 06:34 PM

New evaporator, new dashpods, condenser, o-rings, txv,compressor, filled with ester and a whopping 3 full cans of r12. (12oz).

I vacuumed and charged with nitrogen 3+ times.

My aux fan is humming, my sight glass is clear, and have a 30 degree temp drop vs. ambient at the vent at idle.

This was my third attempt. finally got it right. My advice to others: If you are not going to do it 100% correct, you are just wasting your money.

It is 95 degrees, and I cant wait to get in my car again.

Thank you all for your valuable help. I would have never been able to do it without the knowledge of this site.

ps2cho · #2 07-17-2012, 07:40 PM

Get some driving temps!
With my crappy r134a and broken pods letting in ambient air I can pull 40-50F drop while driving depending on ambient. 115F outside I can pull 65 from vents, 90F outside I can get 40F....

....so with that great refresh you've done, you should be able to get really, really cold.

Did you use the 15cc or 17cc compressor?

lorainfurniture · #3 07-17-2012, 07:54 PM

Quote:

Originally Posted by ps2cho

Get some driving temps!
With my crappy r134a and broken pods letting in ambient air I can pull 40-50F drop while driving depending on ambient. 115F outside I can pull 65 from vents, 90F outside I can get 40F....

....so with that great refresh you've done, you should be able to get really, really cold.

Did you use the 15cc or 17cc compressor?

I changed the compressor last year, I'll double check, but I Believe 17.

It was about 95 degrees today with blazing sun, and I was able to reach 38* after driving for about 10 minutes with the blower still on full blast.

I really need to get it on the freeway and drive it for 20 minutes or so to get it to cool down proper. I'm sure at speed, and if I lower blower speed, I'll reach the fabled 34*.

Air&Road · #4 07-18-2012, 09:57 AM

95 Ambient and 38 vent in ten minutes indicates a properly performing 124 a/c system.

DieselJim · #5 07-18-2012, 11:27 AM

Nice Job! Nothing better than success. That one has a lot of labor

Air&Road · #6 07-18-2012, 12:43 PM

Quote:

Originally Posted by DieselJim

Nice Job! Nothing better than success. That one has a lot of labor

Yep, that wasn't a repair, it was a PROJECT! Good work!

JamesDean · #7 07-18-2012, 02:52 PM

Amazing numbers!

I wish my 201 was as good at idle! Jealous.

All my equipment is still stock. Probably should be all changed over as well.

RobertFini · #8 07-18-2012, 09:14 PM

The only problem I have with the A/C in my '94 W124T is when the car is sitting still and the aux fan is not running - the outlet temperature goes WAY up. Everything is fine, as long as the car is moving or the aux fan is on. Have any suggestions?

Best Regards,
Rob

JamesDean · #9 07-18-2012, 09:18 PM

Perhaps it is undercharged? I had the same problem in my 126 420SEL. Now its nice and cool at idle and at speed, maybe a 5 degree difference.

lorainfurniture · #10 07-19-2012, 12:06 AM

Quote:

Originally Posted by RobertFini

The only problem I have with the A/C in my '94 W124T is when the car is sitting still and the aux fan is not running - the outlet temperature goes WAY up. Everything is fine, as long as the car is moving or the aux fan is on. Have any suggestions?

Best Regards,
Rob

The aux fan should turn on within a few seconds (give or take). Your problem is that the aux fan is not running all the time.

It is activated by pressure, so an inadequate charge could do it.

lorainfurniture · #11 07-19-2012, 12:14 AM

After driving 30 plus miles, I find myself setting the thermostat dial at about 78*. That causes the heater valve to release, allowing some heat to mix with my a/c. It is COLD.

I am also enjoying properly working cruise control. (thanks James dean)

It's been a good week for the Mercedes.

ps2cho · #12 07-19-2012, 01:54 AM

You make me really look forward to my plans to refresh. Basically, exactly what you did.
Only change I may do is put the larger condenser in from the later models, BUT I have to deal with making or getting different hoses to reach the different location that is on the larger condenser...makes me consider not bothering.

lorainfurniture · #13 07-19-2012, 02:50 AM

Quote:

Originally Posted by ps2cho

You make me really look forward to my plans to refresh. Basically, exactly what you did.
Only change I may do is put the larger condenser in from the later models, BUT I have to deal with making or getting different hoses to reach the different location that is on the larger condenser...makes me consider not bothering.

I considered doing the same after reading your dual fan thread. Cleveland is generally milder, so I figured it would be a waste of money and effort.

It is my opinion that the 300e a/c is adequate. We have had temps in the 90's with extreme humidity, and the cabin still cools nicely.

One bit of advice: don't look at your pressures when charging, charge by weight.

I charged 3 12 ounce cans In the system. That puts it slightly under the factory charge. The last can took a long time to go in, I had to get the can very hot, and had to raise the idle to about 2k for quite some time.

ps2cho · #14 07-19-2012, 03:24 AM

Thanks. I get the opposite here, very dry, but temps ~115 in summer.

It seems everyone says with r134a charge by pressure, but with r12 charge by weight.
Kind of odd

I just do as I am told

engatwork · #15 07-19-2012, 09:15 AM

Mine is still in the shop waiting to be re-assembled. I knew that if I tore it down I would be swamped with customers cars and that is exactly what happened which is a good thing

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