A/C Performance-W124

[lkchris]

Anyone have experience with Smart Vov? Read about at http://www.aircondition.com/vov/main.htm
Our 300E seems to have fairly poor performance around town--needs some revs, it appears, and promotional material for this device makes it sound like a potential solution.

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Kent Christensen
'88 300E (wife's)

[Benzmac]

I guess it would be cool IF you had an orifice tube in your car.

Your car uses an expansion valve that is variable already. No orifice tube here.

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

[jeffsr]

You need to top up your charge. The 300E system with R12 is one of the coldest A/C systems I have ever experienced. My '89 will generate frost on the center vents on a humid day. Check the sight glass (right front engine compartment) on the receiver/dryer. I'll bet you see those "tiny bubbles"..

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Jeff Lawrence
1987 300e
1989 300e
1987 BMW 325

[JCE]

I was just told that the AC on my 87 300E has a very small leak - the air didn't seem as cold as usual and it took 2 lbs of r12 to bring it up to full. The measured temp at the center duct was 42F!!! the tech added a little dye, and the next day traced the leak. When I fix the leak at the end of summer I will probably convert to 134A, but I agree the AC is plenty cool when full. I was told that the system is a little slow to cool a hot car when first turned on, but that this was fairly typical for w124s. I compensate by leaving the sunroof cracked open while parked, rolling down the windows to flush out some of the heat when I start up, and then running on recirculate for a few minutes. It's true - frost on the center vent on a humid day!

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JCE
87 300E, 65k miles
Smoke Silver

[This message has been edited by JCE (edited 06-18-2000).]

[Zoni]

Just finished a 250 mile round trip and A/C on my 91 300E was great (very cold). Started up this morning and it sounds like the bearings are going. Local mechanic advised that if we couldn't recover the R-12 would have to convert the system (about $1,500). Is it true that R-12 is not available any more?

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1991 300E

[Crowe]

R12 is no longer being mamanufactured in the US, but it is still available, it is just expensive! Since 1993 to purchase Freon in containers holding less than 20 pounds, the EPA has required the purchaser hold a 609 Motor Vehicle Air Conditioning (MVAC) Technician Certification. Any shop doing AC work now should already have a recovery system.

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Tony

1988 300E Metallic Blue Black/light Gray MB-Tex leather interior

MBCA Member

[Zoni]

My shop has a recovery system but they are suggesting that if the compressor needs replacement it's agood idea to convert from R-12........any opinion on this stance would be appreciated.

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1991 300E

[Crowe]

I have done a lot of research on AC problems and issues with the 300E recently. The consensus seem to be that the refrigeration efficiency of R12 is better than R134A, everything else being equal. The Nippondenso compressors used in your vehicle have pistons coated with Teflon and during failure, the resulting mixture of burned oil & Teflon can form a coating throughout the system. Another problem you may expenience is the 300E is prone to leaks in the evaporator. This is a very expensive repair. The question of coversion to R134a depends upon the nature of your repair (how extensive) and one of personal preference. I personally prefer to stay with R12 for as long as possible.

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Tony

1988 300E Metallic Blue Black/light Gray MB-Tex leather interior

MBCA Member

[ctaylor738]

I would suggest you search on "A/C conversion". There is a huge amount of opinion on this. The consensus AS I UNDERSTAND IT is that the following MUST be replaced if you convert:

Compressor and clutch $425 - $1200
Drier and switches - $100
(You will need these even if you don't convert)

Expansion valve - $50

MOST recommend the replacement of the manifold pipe - $353 - $684

SOME (Benzmac) recommend the replacement of the condensor. - $250 - $350.

ALL PRICES ARE PARTS ONLY!

You will also need to flush the evaporator and condensor if you don't change it.

The benefit is that you will be environmentally responsible and won't have to pay $50 per pound for freon.

My advice - if you are going to keep the car for several years, do the upgrade.

Otherwise, buy the rebuilt Behr compressor/clutch for $400 from PartsShop, add the drier and switches and stick with R12.

WHATEVER YOU DO, DO NOT ALLOW THE COMPRESSOR TO SEIZE! WHEN THAT HAPPENS YOU RUN INTO A WHOLE ADDITIONAL LEVEL OF PROBLEMS BECAUSE YOUR SYSTEM WILL BE FULL OF TEFLON COATED GOO!

GOOD LUCK.

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Chuck Taylor
Falls Church VA
'86 300E 5 speed
'95 C220 (wife's car)
'98 Porsche Boxster
Past: '79 280E, '82 300D (18 yrs), '77 240D,
4 250C's

[Zoni]

Thanks Chuck....so far I haven't run the A/C and have disconnected it so someone else can't run it either......been waiting to hear opinions on this. Car has 128K on it (originally sold in Canada) and other than this problem car is in great shape and I see no reason to get rid of it.

[JCE]

If I understood my tech correctly, he said if the compressor had not failed, the MB bulletin he read rcommended changing several items (sorry, I can't remember which ones, but he said it was not necessary to replace the compressor if it hadn't failed) and flushing/evacuating the system with r12 several times before final evacuation and filling with r134a. His ballpark estimate for repairing the leak and doing the conversion was about $400. He said he has done a number of cars following this procedure with no problems. Any input or comments would be appreciated. (BTW, he charges a little under $40/lb for r12).

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JCE
87 300E, 65k miles
Smoke Silver

[This message has been edited by JCE (edited 06-19-2000).]

[Crowe]

JCE, if you can get your AC system repaired and converted to R134a for $400, write him a check today. If your leak turns out to be the evaporator or any number of other items, the bill could run as much as $2000. The conversion itself will require some new parts regardless of the leak.

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Tony

1988 300E Metallic Blue Black/light Gray MB-Tex leather interior

MBCA Member

[J.HIDALGO]

Well, recently I replaced basically the whole system in my 86 300E. I had the same dilema so, I did a lot of research and decided to keep R-12. Among the reason:
1. R-12 more efficient that r-134
2. R-134 molecules smaller than r-12, more prone to leak.
3. If flushing not done correctly for conversion, may cause some problems in the future.
4. Age and mileage of my car (even for a MB).
5. If the job is done right, you will not have a leak. So, does it matter if you have R-12 or r-134. What are you saving? About $100 on r-12 (current prices). We all know, labor is where you are going to get hit the most.
Just my .02
J.Hidalgo

[Crowe]

Good general discussion of R12 vs 134a and conversion at the following website: http://www.allpar.com/eek/ac.html

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Tony

1988 300E Metallic Blue Black/light Gray MB-Tex leather interior

MBCA Member

[ctaylor738]

The whole point of converting to R134 is that R12 is going to get more expensive and difficult to find in the future, and is actually illegal in some locations. A one-year fix is one thing, but the a long-term keeper should probably be converted.

Zoni -

I don't know what your mechanical competence is, but to change the compressor, manifold hose, expansion valve, and drier/switches is not rocket science. You can do this yourself and then take it to a good AC shop for flushing and charging.

Good luck.

Chuck