Does anyone out there happen to know what the R134a capacity is for the 83 300d Turbo?

I need to evacuate my A/C system so I can replace the expansion valve and ETR. Finally, refill the system with R134a.

Secondly, is there a way to flush out the A/C system?

Thanks in advance,

BG

I had good results with 80% of the R12 amount on the label under the hood.

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

Have you ever had any issues with your A/C not blowing cold air?

My system:

83 123
Running R134a
New compressor
New Dryer
New rebuilt Mono Valve
New blower motor
About to replace the AC Expansion valve & ETR
New rebuilt AC control unit
Replaced all of the vacumm elements inside the cabin.

Am I forgetting anything that might need to be replaced? is there a way to completely flush out the system?

Symptoms are:

1. When it is hot out, AC only blows room temperature air even when compressor clutch is engaged, Aux Fan is running, and also after a new charge of R134a.

2. AC hoses in engine compartment do not get so cold that they start to sweat.

Thanks in advance,

Really stumped and sweaty..

BG

You need some gauges. Post the pressures for the low and high sides with the clutch engaged.


There is pretty much no toher way to diagnose the problem.

use the search feature, there is lots of info here on how to deal with AC failure.

You can flush the whole system....should replace expansion valve and drier and all o-rings, then you have to refill the system with oil.

If you want to DIY you will need said gauges, vacuum pump, and a flush gun (runs off shop air or a compressor). All those tools cost about $300 if you go cheap. Solvent to flush the systen is $40, o-rings are really cheap, oil is really cheap, drier and expansion valve are available at Fastlane...not too expensive....

good luck! There is a pretty steep learning curve (again search is your friend) but once you learn it, it's not too bad...

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

Is it best practices to always replace the drier when doing this type of task?

Spend some time, search, and read. I did and concluded that the best amount of 134a in a 123 is zero. I stayed with R12 and I'm glad I did.

__________________
Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/mercedes-benz-cars-sale/296386-fs-1-owner-83-mb-300d-turbo-rebuild-parts.html

I hear ya... However, The conversion was done before I bought it.. Is it possible to go backwards without TOOOO many issues?

YES! And I promise you that you will be well satisfied. My '87 124 was converted to 134a by a previous owner & after suffering through one summer of way-less-that-cool AC I re-converted to R12.

As suggested above, use the search function. Also, as recommended above, you WILL need a set of gauges. Keep in mind that the gauges for R12 are different that those for R134a (I think). They can be had for minor $$$ from EBay, Craigslist, local pawn shops, etc. The set I bought for $15 is worth its weight in gold to me.

Posts by LarryBible, VSTech are the most informative & accurate. Be aware that there are a lot of "shade-tree" AC repairers out there that may lead you astray. But those two guys have forgotten more about auto AC systems than most remember. There are also a couple of other guys that give good info, but can't remember them right now.

R-12 is not as expensive as many people think & it is what your car's AC system is designed to use. If you just want to get by for the rest of the summer, use 134a. But plan on "upgrading" to R12 as soon as you can. There is no way I would ever go back to R134a - I would almost as soon do without AC (might as well, it's performance is about the same).

__________________
1987 300DT
2002 Ford F-250 7.3 Crew Cab Short Bed

Thanks for the info.. I will convert back as soon as it starts getting a bit cooler.

BG

My$.02:
My 240d blows 42* from the center vent at idle on a 105* day

It has.134a in it

Ymmv

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

134 can work fairly well with a good compressor, a clean condenser, a fully flushed set of coils, a new expansion valve, a new reciever/dryer, and an EXACT amount of oil in the system.
fairly well means up to about 90F outside and driving in a lot of shade, on the highway, you will get decent cooling from the vents. it'll take a LONG time to cool a car in hot sun, with no tint on the windows, at idle. If your area sees 90+F high humidity days regularly, you should strongly consider using R12.
you still need to flush the coils, and clean the condenser and straighten all the fins, and change the reciever/dryer and the expansion valve, and add the exact amount of oil, but the efficiency of the refrigerant will net you 40F temps at the vents on HIGH in 95degree days in high humidity, and cooling will be far superior.
it'll still be hot on super hot days, the 123 a/c is poorly designed, get used to it if you live in the ultra hot areas. and tint the windows. it'll help!

__________________
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!

a flush gun is a pretty simple device. basically it's a can you pour solvent into that has hose connections to connect to your manifold or straight to your coils and lines in the car with a blow gun connector with a rubber stopper. the above advice is good (especially the one recommending me and Larry!)
where are you located? update the user CP above, and put it in so we'll know where you are!

also, I don't recommend using compressed air for the flush process, it has moisture in it, I recommend only using a dry gas, like Nitrogen or Co2... craigslist is your friend in looking for a/c service tools and nitrogen tanks and regulators.
keep the questions coming!

just remembered that AZ (probablu any Mcparts place) rents flush guns.

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

I'm out here in Spring, Tx just north of Houston where it gets pretty hot and balmy.

I typically do computers so I would be willing to barter on the work. I'd pay for the parts...
www.systempros.net / Computer Services