Hi there.
Today I bought a r-134 retrofit kit for my 420 sel. the car has a Nippondenso compressor. The kit came with three fittings (two red and one blue) two caps and some ester oil compatible with r-12 and r-134a. What should I do next, I don't have the proper equippement to clean or charge the system. Can I change the oil myself, where to put the fittings and what should the shop do on the car?

Thanks

Mike

Step 1, take back 134 kit.

Step 2, take car to technician that knows how to make system stop leaking, then use r-12.

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Benzmac:
Donnie Drummonds
1991 GMC Syclone
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Step 1.Determine how much car is worth
Step 2.If cost of repair,it can run into thousands of dollars sometimes,is more than/almost near the car 's worth,determine whether AC is worthwhile in Canada,where it's needed for less than 2 months per yr max.
Step 3.By all means try anything if you dont want to spend further money on car/or if you dont mind messing up your AC in the process.

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Tom 1992 300E 2.6

I too was tempted by one of those $30 kits at my local BJ's wholesale club. I passed. I got my leaking expansion valve, 4 O-rings, and 3 lbs of R12 done on Friday. Cost was a bit less than $400. Today it was +31 deg C. and humid, and it was nice to have COLD AC.

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Robert W. Roe
1984 300SD 170K mi

I have a few vehicles, a Benz being one of them, that I have changed over. I have a vacuam pump, guages, etc.

That said, I agree with Benzmac. If you can fix the leak and stay with R12, you will be much better off.

From previous posts and online conversation with Benzmac, it's obvious that he has massive experience in both changing systems over and repairing them to stay with R12. These are real "words of wisdom" you're getting from him. Their very valuable words of advice, but you're getting them for free.

Good luck,

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Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

I definitely agree with Benzmac. Most Benz A/C systems are marginal at best, and converting them to 134 only compromises them further. An R-12 system with no leaks should work well and hold charge for a long time. My '82 Volvo has very cold R-12 A/C and was last charged 3 years ago.

Cost of repair:
For those of you who have followed my experiences with my 180K 300E, here is another chapter. I am not complaining, but in sharing this, I hope that others will learn of the complexities, expense, and pitfalls of the 124 AC system.
When I bought the 300E in April, it had a frozen compressor, and no power to the compressor. I decided to convert it to R134 since I really enjoy the car and want to keep it around for a while.

Here is a summary of what I spent and what happened.

Parts:

From Partsshop:

Rebuilt Behr Compressor (incl clutch) - $465
Drier bottle and switches - $110

From Performance Analysis

Manifold pipe - $400

From dealer

Expansion valve, oil, seals - $120

My plan was to install all of the new components, and take it to a shop for flushing and servicing.

I replaced the compressor, after following the directions to add oil. The Behr unit is shipped without a speed sensor, or manifold pipe connector, so I installed those from the old compressor. Installed the compressor to make the car driveable. So far so good.

With the parts installed, the car was ready to go to Silver Star Motors for flushing, evac, and charging. Shortly before took it there, I discoved that the compressor had leaked a quantity of oil. The shop determnined that this was caused by an improperly installed speed sensor. The result was that the shop R/R'd the compressor, drained the oil, and refilled it. In the course of doing this, they discovered that the belt tensioner, and shock absorber were shot, and replaced them. They also replaced the hose from the condensor to the drier. Then they flushed the system until they quit getting metal out, installed the expansion valve, evac'd it, and refilled it with R134.

Total bill at Silver Star - $1127 ($630 labor, $497 parts and misc.)

Total cost for entire job - $2,342.

Not complaining or feeling screwed. Just want to make others aware of what they are getting into when they undertake major repair to a 124 AC system. I could easily have added $1000 to this total by using all Mercedes parts.

Lessons learned -

Be damned careful to get the compressor speed sensor on correctly and make sure it does not leak before installing the compressor.

System now works great - good luck to all who attempt this.

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Chuck Taylor
Falls Church VA

Cautionery tale for Ontarians:
Well, after several years of ownership of two 124s, I have come to regard these (so-called) "climate control systems" with a mixture of frustration and fear. It's not as poetic as it sounds...
Although I've received help on this topic before (thanks Benzmac and MBDOC), I have some more details to add, so I hope you'll bear with me.

The AC was inoperative when I bought the car (mistake #1). I took it a friend of the family with an AC shop (mistake #2). After having invested about $1000 in parts with this guy and dozens of hours in diagnosis, I let him "finish" the job. Eventually, the compressor, condenser, receiver/dryer, and the pushbutton control unit were all replaced. The AC had the habit of cutting out and not reengaging until the car was restarted (difficult on the highway...). Thought I had that one solved with the relatively recent replacement of the belt tensioner damper, but no. Well, here are the symptoms, and I apologize for the length of this post.

At any ambient temp, car stationary:
-the compressor cycles normally when idling
-compressor cuts out if revved momentarily to ~2000rpm and stays off for ~10 minutes before reengaging.

At moderate ambient temp (~21degC), while driving:
-AC operates fine, even though 2000rpm is frequently achieved

At higher ambient temp (~25degC), while driving:
-AC cuts out indeterminately (read: I can't always judge when), and then stays off for 5-15 minutes while I lose 5-15 liters of sweat.

I'm at my wit's (and wallet's) end with this problem. The belt tension seems fine. I should add that the compressor is aftermarket and that the pressures have been checked by a MB dealer. Really appreciate any and all input from you kind souls. Will mail cheesecakes.

Regards,
Nick

[This message has been edited by Nick Jamal (edited 05-08-2000).]

[This message has been edited by Nick Jamal (edited 05-08-2000).]



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Tom 1992 300E 2.6

Chuck and petaling,

Thanks very much for sharing your experiences. Seeing your historys could prove very valuable to me someday. I cross my fingers every time I start up my 300E. I have nightmares about having a serious AC problem. I love the car so much, and would really hate to go through such a nightmare.

Chuck, you are a patient man.

Thanks to both of you,

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Larry Bible
'84 Euro 240D, 523K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Petaling, what you describe with your A/C sounds like an excessive pressure situation which will trip the high pressure cutout switch. The compressor will stay off line until the pressure drops and the switch closes. The fact that at speed and at a lower ambient temp, it works indicates that it is a combo of heat and pressure working against you. Again, it will stay off until the system cools enough to let the high side pressure come down. You've got either too much freon or one of the system sensors is malfunctioning. Make sure they check the high side pressure at idle and under increased heat. I'll bet it will be above spec.

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Jeff Lawrence
1987 300e
1989 300e
1987 BMW 325

[This message has been edited by jeffsr (edited 07-12-2000).]