Proper R134A Conversion for 124? - Page 2 - PeachParts Mercedes-Benz Forum

JamesDean · #16 05-22-2013, 12:43 PM

Yeah, the OM603.970 was the only diesel to get the 10P17C. All other cars eventually got it it looks like. I wonder why the other OM60x series diesels never got it...

JamesDean · #17 05-22-2013, 12:52 PM

According to the PDF charts :

At 80F ambient, vents will be 43-59 F (40% - 90% humidity)
At 85F ambient, vents will be 47-66 F (40% - 90% humidity)

Humidity is in the 60%s right now.. so I would be a just a bit left of the middle..so.. maybe 50F if 80F ambient, 55F if 85F ambient.

Damn, that just seems crappy. Why did they not give this poor engine the bigger compressor?

I wonder if my 190E has a 10P17C on it... The motor was a transplant from a 300SEL...

lorainfurniture · #18 05-22-2013, 01:40 PM

my 300e has the 15 compressor and is very cold. Only when stuck in traffic on a 95+ degree day does the ac system become marginal. Even then, its ok.

Are those temps based on 134?

lorainfurniture · #19 05-22-2013, 01:46 PM

I have conquered w124 Air conditioning. Now kneel.

Here is the thread. Corrections are: I do have the 15 compressor, and I charged with nitrogen to 200psi.

JamesDean · #20 05-22-2013, 01:51 PM

The numbers came off the charts in the PDF. I would believe they are for R12.

lorainfurniture · #21 05-22-2013, 01:56 PM

You have to realize that when the car is running it starts to recirculate already cooler air. Reading back on my old thread, 30* drop is what you would be looking for.

Zulfiqar · #22 05-22-2013, 02:05 PM

by reading here, it seems that the only different bit is the condenser fans, I know my car is R134a, has twin fans at the front and I get numbed fingers from the cold - so much that I have to dial it down to 78F to be comfy.

As our condensers arent worth it, I believe it would be mighty beneficial to use a multipass condenser or even a refrigerated dryer (seen that in porsche once)

Air&Road · #23 05-22-2013, 02:42 PM

James, it would be MUCH more time and cost efficient to simply reverse convert to R12. Just get a new receiver drier and an o-ring kit. Break all lines and flush them all. If you don't have a flush gun use brake kleen. Blow out the lines thoroughly, preferably with an inert gas, but compressed air if you have nothing else. Rinse the compressor with mineral oil, not solvent.

When you put everything back together distribute the oil in several components and put the r/d in place as the very last step and be ready to evacuate as soon as the r/d is in place. Then charge with R12.

I've reverse converted a number of vehicles with great success. With R12 prices being as low as they are these days, this is a very practical thing to do and will not only save the cost of all those parts, but offer less chances for problems.

Hope this helps.

Air&Road · #24 05-22-2013, 02:43 PM

Quote:

Originally Posted by Zulfiqar

by reading here, it seems that the only different bit is the condenser fans, I know my car is R134a, has twin fans at the front and I get numbed fingers from the cold - so much that I have to dial it down to 78F to be comfy.

As our condensers arent worth it, I believe it would be mighty beneficial to use a multipass condenser or even a refrigerated dryer (seen that in porsche once)

There are other differences including the higher capacity 10P17 compressor. The 124 cars designed for 134 seem to work well, retrofitting an earlier car is not a good plan. It is a very poor candidate for 134 conversion.

JamesDean · #25 05-22-2013, 02:47 PM

Quote:

Originally Posted by Air&Road

James, it would be MUCH more time and cost efficient to simply reverse convert to R12. Just get a new receiver drier and an o-ring kit. Break all lines and flush them all. If you don't have a flush gun use brake kleen. Blow out the lines thoroughly, preferably with an inert gas, but compressed air if you have nothing else. Rinse the compressor with mineral oil, not solvent.

When you put everything back together distribute the oil in several components and put the r/d in place as the very last step and be ready to evacuate as soon as the r/d is in place. Then charge with R12.

I've reverse converted a number of vehicles with great success. With R12 prices being as low as they are these days, this is a very practical thing to do and will not only save the cost of all those parts, but offer less chances for problems.

Hope this helps.

I agree, a properly done R12 conversion seems to be the best approach. Proper being everything resealed, thoroughly cleaned, flushed, evacuated etc.

Quote:

Originally Posted by Air&Road

There are other differences including the higher capacity 10P17 compressor. The 124 cars designed for 134 seem to work well, retrofitting an earlier car is not a good plan. It is a very poor candidate for 134 conversion.

I was looking into these 134 cars. According to the EPC, the 95 E300D and my 91 300D share the same, evap, condenser and compressor. It would seem MB did not really do much in the way of 134a (at least on the E300D, I didnt look at the rest of the cars)

I do like the quick-connect ports though

will miss them when its converted back

Air&Road · #26 05-22-2013, 04:34 PM

There were three different compressors used on the 124 cars, two 10P15's and one 10P 17. You never know what you're gonna get. I think that most all the late cars had the higher capacity 17's while very few early cars had anything except the 15's.

JamesDean · #27 05-22-2013, 05:38 PM

Based on what I saw in the EPC. The diesels all got the 15. Im not sure what the difference betwen the 10PA15C and the 10P15C is.. but I know all the diesels except the 350 got the 15. The 350 got the 17.

The 17s made it to the gassers..later on i think. not sure who or when.

Im about to leave work, we'll see how it does! Thanks for all the help everyone! 80F / 70% humidiy!

JamesDean · #28 05-22-2013, 10:24 PM

Best I got was around 53-55 at the vent or so. 85 degree ambients...which is OK performance. It falls in the range according to the chart..

Tomorrow I'll drive the 190E which is charged with ES-12A (not Larry's favorite but I was in the middle of suspension rebuilds and really didnt have the funds/time for a proper install. I think if I ever get around to it..I'll mate the 10P17C compresssor for some extra headroom

But I'll get numbers and see. I am going to bet it will do better than 134a. I know it does ****ty at idle..

cbc atl · #29 05-26-2013, 01:18 AM

Proper? You make the call, but for ten bucks worth of refrigerant you can evacuate, refill and chill.

No replacing anything else: no new seals, no new dryer, no new oil---nothing.

Next year, add another can; mine was done Feb 2012 and just added another can last week.

Did the research - see:

Propane(R-290)&Isobutane(R-600a) 60/40

My posts:
AC compressor will not engage after evacuation - Benzworld.org - Mercedes-Benz Discussion Forum

Charging with propane...how? - Benzworld.org - Mercedes-Benz Discussion Forum

A very sad day indeed - should I keep it or sell it at a low price - Benzworld.org - Mercedes-Benz Discussion Forum

Well its that time of year again! - Benzworld.org - Mercedes-Benz Discussion Forum

Not my posts:
Charging with propane...how? - Page 2 - Benzworld.org - Mercedes-Benz Discussion Forum

R-12 vs Propane vs R-12a (time to recharge A/C) - Benzworld.org - Mercedes-Benz Discussion Forum

Using propane instead of R-12 for A/C - Benzworld.org - Mercedes-Benz Discussion Forum

AC problem solved with propane- Did I plan for suicide - Benzworld.org - Mercedes-Benz Discussion Forum

Other stuff
And apparently you do not have to change the drier with this either

Pasted from

This gives charges of approx. 40-45 % of R 22, R 12, R 134a or R 404A charge in grams, according to the data from table 1, which also corresponds with empirical values.
hydrocarbons21.com

Per ghg: [60% propane / 40% isobutane works better.. pressures are correct

Pasted from

To evacuate or not when going from R-134a to R-290 & R-600a? Yes.
Per ghg - paraphrasing of course: there is a possibility of the R134a breaking down to acids when exposed to moisture. Since propane could have moisture then it seems necessary to evacuate. If not evacuated then moisture level should not exceed 10-20ppm; however, if it is evacuated the moisture level can go up to even 1,000 ppm.

1100 grams R-12 - - that is what our w124's call for. And then I calculated the rest:

38.8 oz. R-12
40 - 45 %
15.42 - 17.46 oz.

And @ 60/40 by weight
Propane/Isobutane (oz.)
9.25/6.17 - 10.47/6.98
If 8 oz. of Giga then 1.2 oz. Propane + 6.8 oz. of Iso-Butane
Need additional 9 oz. Propane

• GigaPower Fuel 110 Gold - This is the one I chose and your calculations may differ based on the refrigerant you choose.
Giga 250 grams = 8.818 oz. Then 1.3 oz. (R-290) + 7.5 oz. (R-600a)
Need to use 7 oz of the R-600a and then an additional 9.2 oz (R-290).

Can (GP250G) is acutally 7.76 oz. --- only need 7oz and then 9.2 oz of (R-290).

Thanks,
cool in atl

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