Convert to R134 or stay with R12 freon for AC unit? - PeachParts Mercedes-Benz Forum

jbach36 · #1 06-26-2012, 06:25 PM

My car is low on freon due to a leak. We can find the leak and stop it, and probably just add more R12 freon, and be done.

However, my general mechanic is saying this might be the time to convert to R134. He said to do so, we'll have to change out some part, suck out the R12, and put in the new stuff. He also said he's not had good luck with R134 on Mercedes; it could cool worse than my R12 that is currently low on freon. As we all know, the Mercedes a/c system is not a good one to begin with. He said the gas Mercedes have it even worse, as some of the freon is diverted to cool the fuel line. Thankfully, I have a diesel and it doesn't need that.

So, what's the best thing to do, and how is R134 cooling your Benz?

Also, has anyone tried the R134 Synthetic AC Booster? It says up to 18% cooler than any other freon (including R12). Autozone has it, it's $35 can, vs $15 for the regular R134. I wonder if it works, and if it can be mixed with regular R134.

Jeff
1991 300d, 175k

engatwork · #2 06-26-2012, 06:57 PM

and charge r12 to spec and be glad it works as good as it does.

jbach36 · #3 06-26-2012, 07:33 PM

Quote:

Originally Posted by engatwork

and charge r12 to spec and be glad it works as good as it does.

Soooo, what are you saying, exactly?

lorainfurniture · #4 06-26-2012, 08:37 PM

Yes that's exactly what he's saying. The best your ac will ever be is with a
Properly filled, well running r12 system.

In defense of Benz, the ac usually works pretty well until it hits 95+ and you get stuck in traffic. The one or two times that has ever happened to me, I just put the car in neutral and raised the idle.

Bio300TDTdriver · #5 06-26-2012, 08:41 PM

Quote:

Originally Posted by jbach36

Soooo, what are you saying, exactly?

If you spend a few seconds searching on this site you will find plenty of members that are unhappy with the R134 conversion.

Fix the leak and keep the R12. You can thank us later.

vstech · #6 06-26-2012, 10:40 PM

the 91 124 can function fine on 134, IF the conversion is done properly. AND IF it does not exceed 100F temps, outside, and you maintain speed, not sit at idle.

the 124 is FANTASTIC cooling with R12, but if you get ahold of a dual fan setup from a 93+ 124, get the fans AND the resistor behind the driver's headlight. get the condenser as well if you can. you will have nearly perfect a/c with 134.
if you clean the coil, lube the bearings in the current fan, fix the leak and charge with R12, you will have ice cubes blowing out the vents. it'll be even better if you tint the windows!

jusme · #7 06-26-2012, 10:54 PM

Nice to hear John!

I haven't finished my 87 300TD, and was worried about cooling the whole cabin. Nice to know it's well suited for the job.

Quote:

Originally Posted by vstech

the 91 124 can function fine on 134, IF the conversion is done properly. AND IF it does not exceed 100F temps, outside, and you maintain speed, not sit at idle.

the 124 is FANTASTIC cooling with R12, but if you get ahold of a dual fan setup from a 93+ 124, get the fans AND the resistor behind the driver's headlight. get the condenser as well if you can. you will have nearly perfect a/c with 134.
if you clean the coil, lube the bearings in the current fan, fix the leak and charge with R12, you will have ice cubes blowing out the vents. it'll be even better if you tint the windows!

vstech · #8 06-26-2012, 11:08 PM

My 87TD has had 134 in it the entire time I've had the car. it cools FRIGID air on my hands... up to about 93F outside temps at idle... above that, I've got to be moving to keep cold air out the vents. I have the newer condenser, but still have the original aux fan. I also CLEAN my condenser every year. it's so easy to clean the evaporator, it's a good idea to do it on the 124 regularly. just pull the wiper, and the blower housing, and vacuum out the coil, then gently wash it out. pow, nice cool air and strong clean flow!
I also have a NEW fan clutch, but the original aluminum fan... I will upgrade to the 606 turbo fan/clutch before it gets too hot this year(supposed to hit 100 this week...)