Does anyone know for sure if there are any differences between a R12 and R134a condenser for a W124 wagon?

I'm trying to extract the most A/C efficiency, and was wondering if the differences between the two are great enough to warrant a swap.

Thanks,
:-) neil

PS: also any caveats when changing out the condenser? Fitting changes, hoses, etc.?

I don't think there is a difference. I recently changed over to 134a in my 380SL and all I did was replace compressor and drier (and of course flushed out the system before vacuum and recharging). I replace the compressor only because it was weak. Now the car is ice cold.

Hello..i went thru the same dilemma a few years ago..asked everybody..got all kinda answers..the bottom line was that i would have to spend a fortune..or replace things so a shop can refill my R12....my car was an 88300E...so i didnt really wanna spend all that money in just to get cold air..so i just bought the adapter niple a few cans of R134 some oil..released the old gasses.filled it with somke oil and 2 cans of R134..released it(flushed it) refilled it again ...and it worked works ever since...

I didn't include some important information.

I have already changed over to R134a, only because the compressor from a 1995 C36 was already R134a.

However, at temps above 105-farenheit, the air wasn't particularly cooler.

Hence, to *complete* the change over to R134a, I am contemplating replacing the condenser IF the R134a does a better job than the R12 condenser.

Thanks,
:-) neil

One Thirty Four A will not get as cold! In my R12 cars I get 34 degrees at the vent. With the 134a maybe 48 degrees. Major benefit in favor of 134a is it cost $4 to $5 a pound as opposed to $30 to $50 in the case of R12 if you need a recharge. Find the V-Kool Dealer in your area to put on the invisible window tint to drop the heat load and be $$ ahead with R134a.

In all fairness I am a V-Kool Dealer in Kansas City ( 4th largest in the nation ) but spent 20 years in the HVAC business and still keep my license. We do not do cars here, only residential and commercial.

In many major markets there are automotive ( curved glass ) dealers. I do have it on all of the windows ( including the windshield ) of my Axiom and it passes the stringent Missouri inspection because it is simply invisible while blocking 55% of the heat through the glass.
I love my "new 1984 380 SL."
Best Wishes,
John,
Licensed HVAC Master Mechanic

I have always been told that since R134a is not as efficient at cooling as R12, newer cars with R134a have larger condensors to allow the car to cool better.

My 1993 300E (3.2) came from the factory with R134a, and it has the coolest a/c I've experienced on any car I've ever owned, which inlcudes a large assortment of American and Japanese cars (and one Audi ).

I have always assumed that the condensor on my car is different than 300E's with R12.....

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

I own two 124 cars - one with R-12, the other with factory R-134a. The R-134a car actually has much better air conditioning - it cools down faster and stays much cooler in stop-and-go traffic. I agree with Paul, the 1993 has one of the more powerful a/c systems I've experienced.

The condensers between the two cars are not identical. However, only the connections for the refrigerant input/output are different. The condensers themselves are pretty much identical in terms of size, design, and construction. So it appears the factory did not radically change the condenser design when converting to R-134a.

- JimY

Interesting.

If the difference is just in the fittings, then I wonder why cars that are converted from R12 don't cool as well.

There must be something else different, then.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Jim -

Actually, thats not correct. While the condensers in your vehicles may appear quite similar in appearance, there is a significant difference in their design and construction.

The R-12 system uses the old-style tube and fin condenser whereas the R-134a system uses the parallel flow style of condenser. The PF condenser is superior in cooling performance to the tube and fin design but is more expensive to manufacture and quite difficult to thoroughly flush in the event of a compressor failure.

To the best of my knowledge, M-B factory fitted all '80s and '90s decade USA R-12 equipped vehicles with tube and fin style condensers, with the exception of the '91 350 SDL, which used a PF style condenser (126 830 29 70). This condenser can be used as a replacement for the R-12 condenser 126 830 27 70 by those looking to improve R-12 cooling performance or R-134a refrigerant conversions in W126 vehicles. The 29 70 is equipped with mounts for dual auxiliary fans, which greatly aid AC system performance.

I've done some checking and learned that the W124 400E and 500E got R134a from the factory in 1992.

300E (3.2's) and 300E 2.8's got R134a in 1993.

I don't know about the W124 diesel models.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

The diesel model 124's got 134 in '92.

Yes if the system is designed originally for 134 there is no reason that it won't cool as well or better. The 124 cars that came originally with R12 will NOT cool as well with 134. I fully expect that if you could find the condensor, aux fan and all necessary components from a later 134 equipped car, you could make it work as well as Paul's.

Before you do that, however, let's do some very simple math. I would guess that to change condensor and all associated parts assuming you perform the labor yourself would cost a bare minimum of $300 if you found what you need in the salvage yard and I think that is a LOW number. Then you need to fix whatever leak or other problem you may have regardless of refrigerant choice.

Okay, now, R12 can be had for $15 to $25 a can on ebay and it will cost you $15 to take the online test to get your 609 certificate to buy it. You would probably need only three cans for a 124, but let's say you need 4. Four cans at $25 is $100.

So you're going to spend $300, so you can save about $80 on refrigerant. I'm an older fellow and learned my math before what was called "New Math" came along. But, I fully expect that even with "New Math" you will find changing to 134 will cost an extra $220.

R12 is the least expensive component in your air conditioner. Repair what needs repairing, charge with R12 and enjoy being cool. It absolutely blows me away to see some of the incredible trouble and expense people go through to save $50 or $75 on refrigerant. It's like they refuse to do the simple math that is involved.

Good luck,

Allright, I'll take a closer look at the condenser in the 1993 300E. But I'm pretty sure it's a dual-path serpentine tube & fin, just like the 1987 300TD. I can get some photos of the two if we're really interested.

- JimY

Jim,

Does your late series 124 have a dual aux fan or does it still have a single like the early models?

Have a great day,

My '93 has the dual aux fan.

Both fans run at the same time, whether at the slow speed or high speed.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Dual fans on my 1993, same as Paul's. The dual fan cars also have a plastic shroud which forces all the air through the condenser. The early single fan cars just have a fan mounted in front of the condenser - no shroud to direct the airflow. I suspect that has something to do with the better a/c performance of the factory 134 cars.

Of course the 1993 gasoline car has a larger Nippondenso compressor than the 1987 diesel. That likely has a bunch to do with the better idle and low speed a/c performance - the low side won't climb to 45PSI at idle, like it does on the diesel.

- JimY