1982 300TD R134a conversion with parallel flow condensor update!! - Page 3 - PeachParts Mercedes-Benz Forum

dmorrison · #1 07-20-2004, 06:20 PM

Want to keep everyone updated on the R134a conversion I did in my 1982 300TD. This update is provided by the 100 degree day we experienced here in the DFW area

This was the "conversion" which consisted of a complete rebuild of the AC system. All new components-- Compressor, evaporator, hoses, orings, expansion valve, paralell flow condensor, R134a and synthetic oil ( good for R12 and R134a)

The posts.

The plan and comments.

Review of my plans for the AC system, comments welcome

Parallel flow condensor

parallel flow condensor installed in a W123

Synthetic oil and why I used it. Because the system can now go between R12 or R134a WITHOUT FLUSHING.

Ac system rebuild-- synthetic oil R12 to R134a

The new compressor vs. old
Some techs I trust said to never use a rebuilt R4 compressor. 90% of the time they fail after 1-2 years.

Installing the dash
Remember I had a leaking evaporator which started all of this.
Notice the amount of crud blocking the evaporator in the pisture about half way down. This may have a significant effect on your conversion.

Order for installing evap box in a W123.

Compressor seals and hoses.

AC rebuild one step forward-two steps back.

Sooooo hows is it going. The other day it reached 100 Degrees here in the DFW area and I will tell you that the car is very comfortable. I posted that I would like to compare it to a 123 R12 system, but Larry Bibles is not working. I got my daughters 240D system working. Its R12. was low on R12 and after adding a can I could not find a leak with my sniffer anywhere in the system. I spent 2 hours searching and no leak. I have added dye with the last can added to bring the pressures up to normal operating limits and so far no dye in the evaporator drip

So to compare the 2 lets discuss the differences. The 240D has no tinting. I run R12 in a standard system with pressures of 22 low and 265 high. The 82 300TD has R134a. A NEW evaporator as well as everything else. tinting, legal tinting, and a parallel flow condensor. R134a and the aux fan is on all the time. I'll try the system with it in the normal mode.
I think the 240D r12 system cools just a little better, may 5% better. My temperature guage for the vents, I think is wrong. But by driving both cars I think the rebuild to R134a is a success.

BUT here are the caviots.(sp)

I have a NEW evaporator, The blockage of the old one was significant. What is the blockage on the 240D, I do not know. Air movement is good, as good as the 300TD? It seem so. What is your cars evaporator like, That may be a consideration. I wish there was a way of checking them without a boroscope or taking out the dash.

So the conclusion, Go with a parallel flow condensor if you are thinking of a R134a conversion. I will get a new thermometer and post the 240D and 300TD temps.
Use synthetic oil after the flush. If you are not happy with the R134a then converting back to R12 only requires an evacuation and recahrge. No flushing.

I hope we can get someone to post who has done the conversion WITHOUT the parallel flow condensor.

Yes I am very happy with the vent temps, Idle speed temps and the results I have gotten. All comparing it to the 240D With R12.

Dave
7709

Let the posting begin.