AC 'refresh' on SD - Options? - PeachParts Mercedes-Benz Forum

ck42 · #1 05-29-2014, 11:03 AM

I'm looking to see what options there are...or recommendations, for refreshing the AC system on my SD.
From the reading I've done so far, the main improvements to a system seem to revolve around PF condensers and better/more efficient compressors. (understanding that the rest of the system is already in good shape, and no leaks)

As it is, I still have the original Harrison compressor.
1) Is it worth looking into a newer/better compressor model?
2) Would adding a PF condenser to a stock and properly functioning 'stock' R12 system make it work any better?

TheDon · #2 05-29-2014, 12:10 PM

A PF would give you more surface area for the condenser to work but a more efficient compressor will be the beignets and best improvement.

ck42 · #3 05-29-2014, 12:25 PM

Okay! So if I continue to use an R12 system, are there any recommended compressors, in terms of it being considered an 'upgrade' ?
Any models/types I should avoid?

[EDIT]
So it looks like an SD model Sanden compressor is pretty much the way to go. From there, it then appears to be a matter of getting the mounting hardware and the lines done.

charmalu · #4 05-29-2014, 04:42 PM

Haven`t you read any of ROLLGUY`s threads?

http://www.peachparts.com/shopforum/diesel-discussion/334249-gen-ii-616-617-sanden-style-c-compressor-mounting-kit-sale-install-inst.html

Then this one about a dual condenser set up. It is all about surface area to cool the Freon to make it more efficient.

http://www.peachparts.com/shopforum/diesel-discussion/355005-dual-condensers-w123-results.html

Charlie

Graplr · #5 05-29-2014, 04:51 PM

If you are going to use R12 I wouldn't worry about changing the compressor to a Sanden. If you do anything add a second condenser. vstech is currently exploring a kit for 123s and the original poster in the dual condenser thread has successfully added two PFCs.

If your system is currently working and on R12, I'd leave it alone. Is it underperforming? Why do you feel you need to do anything? What are the pressures and temperatures? You may spend a lot of money for little improvement. Most that do all the changes do so because they are running a refrigerant other than R12 and are trying to bring the performance of those refrigerants up to R12s level.

Phillytwotank · #6 05-29-2014, 04:59 PM

With a stock system with everything in working order and r12 should be plenty chilly

vstech · #7 05-29-2014, 06:02 PM

If the 126 ac isn't cooling well the frost stat may need adjustments or replaceing.

ck42 · #8 05-29-2014, 06:35 PM

Thanks, guys.
Since posting, I've certainly read a few more threads regarding PFC's and kits being offered.
As for my system, it works...but I've never felt that it worked well enough. I'm in Georgia, so on the hottest days and with the high humidity, it seems to barely keep up. YEARS ago, I did test the vent temp...and as I recall, the delta seemed to fall pretty close to being in line with what it should be - so, it just seems to me that it just needs to work a little better than stock. So, wondering if maybe a better compressor or PFC might actually help this.

vstech · #9 05-29-2014, 09:19 PM

You could also have the fresh air flap stuck open, and on hot days it cannot keep up with the influx of humid hot Georgia summer air...

Graplr · #10 05-29-2014, 09:54 PM

Quote:

Originally Posted by ck42

Thanks, guys.
Since posting, I've certainly read a few more threads regarding PFC's and kits being offered.
As for my system, it works...but I've never felt that it worked well enough. I'm in Georgia, so on the hottest days and with the high humidity, it seems to barely keep up. YEARS ago, I did test the vent temp...and as I recall, the delta seemed to fall pretty close to being in line with what it should be - so, it just seems to me that it just needs to work a little better than stock. So, wondering if maybe a better compressor or PFC might actually help this.

You need to diagnose the system before contemplating any upgrades. You can get a pair of cheap gauges for about $50 from Harbor Freight or maybe score a good deal on Craigslist. Might as well pick up a pocket thermometer for a couple bucks when you are there to leave in your vent permanently (so you can monitor system performance while driving...I leave them in all my cars).

It makes no sense to look at upgrading when you may get the results you want with a simple fix versus spending a bunch of money only to be in the same boat (I'd say ask me how I know but I'd rather not admit to most of my mistakes!) Check into the things mentioned in this thread and address them first.

Caseyc · #11 05-29-2014, 10:41 PM

I'm keeping a close eye on this...
I want to get the coldest option possible before I move back to Florida.

Graplr · #12 05-30-2014, 09:50 AM

Quote:

Originally Posted by Caseyc

I'm keeping a close eye on this...
I want to get the coldest option possible before I move back to Florida.

What do you currently have as far as the operation of the system and what refrigerant and how much do you want to spend and how much work do you want to do?

cjbrown · #13 05-30-2014, 12:49 PM

Quote:

Originally Posted by Phillytwotank

With a stock system with everything in working order and r12 should be plenty chilly

This.

I just went thru this as well. Found local 'pro' with R12 with the right gauges and test equip, freon on hand. He found a defective (leaking) schraeder valve, replaced it, evac'd, and recharged the system - it blows 45deg at the center vents.

That said, I don't drive the car if it's over about 90deg. The newer cars just blow a lot more cold air. After all, it's a 35 year old benzo this year.

vstech · #14 05-30-2014, 01:58 PM

for florida heat... I'd recommend COMPLETELY cleaning the evaporator and the condenser, to get the most heat transfer surface, then replace the blower motor... yours may be running slowly, bypass the fresh air flap to get maximum cool when you need it, then verify the freeze stat is not shutting off the compressor too early.

fresh R12, and the system will FREEZE YOU OUT OF THE CAR... really... you will have to direct the vents away from your body, and reduce the blower speed, or add in some heat.

Caseyc · #15 05-30-2014, 05:01 PM

Quote:

Originally Posted by Graplr

What do you currently have as far as the operation of the system and what refrigerant and how much do you want to spend and how much work do you want to do?

Well, I just got this new to me 83 240D, and the AC isn't blowing cold at all. The car is in excellent shape and is 95% original (After market battery, driver window switch, wiper blades, and headlights are the only non OE components I could find) .

I just dropped it off today at my local Benz shop to get all preventative maintenance done. AC recharge with 134 is on the list. I asked about converting it over to R12, but the shop owner said he doesn't carry it as it could result in a hefty fine. He looked my system over and noticed it has been converted over to 134 by the PO. He plans to diagnose for leaks and/or faulty components. The fan seems to blow surprisingly hard, and the heat works exceptionally well, although there is a slight leak coming from the heater valve.

How hard it it to check or clean the evaporator? My condenser looks great from what I can see. I don't mind spending a lot when it comes to the AC in this car as long as it does what it's supposed to. The R12 sounds very appealing, but how do I go about finding some without incriminating the shop? If it's illegal to use here in Colorado, I would suspect the individuals that have it, keep it for themselves or select high paying customers.

I fully intend to keep this car till I'm long gone, and will little by little work towards a full restoration while using it as my daily driver. By the way, thanks for all the help.

Kind regards,
Casey

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