AC speed sensor vs pressure in the system - PeachParts Mercedes-Benz Forum

Piotr · #1 07-31-2002, 12:14 PM

I finally put in (i.e. the mechanic put in) a rebuilt ACcompressor in my 1985, 190 D (2.2 l). Oh, they also converted and flushed the system (and, yes, installed new receiver dryer). Guess what-it did not work. turned out that the factory assumed that SOMEBODY will know to replace the speed switch at the back of the compressor (Nippondenso 10P15C) from the old compressor to new one. Well, nobody did and the new compressor is now installed and the system is pressurized and it does not work. Both the garage and the re-builder claim that replacing the switch will release the entire refrigerant from the AC system. However, the switch does not appear to be designed to hold the pressure of the refrigerant. Moreover, when taking out the switch from the old compressor (after it was out of the car), I released a little bit of pressure behind it. It seems that whatever refrigerant was behind the switch, it was not connected to the rest of the AC system. So, the question is, do I have to have the system evacuated before replacing this (*^&%$# switch???
Thanx

#2 07-31-2002, 02:17 PM

You did not contaminate the system because it was under pressure. When it was leaking it was leaking OUT, nothing was coming back in. If when you're finished you have lost some refrigerant, simply add a little more.

Good luck,

Piotr · #3 07-31-2002, 03:18 PM

Thanx, I understand this (they converted from R-12 to R-134a, so they had to flush the system, although I know of a couple of people runing mix of both refrigerants with no ill effects!), bit the question is:
If I remove the plug from the installed new compressor and install the switch, will I discharge the system (and have to completely recharge it again)?

Thanx again

psfred · #4 07-31-2002, 09:58 PM

The shop should do this for you without charging you, since they left it out in the first place. I would have refused to accept the car as finished and refused to pay for a job half done.

I don't know if you can do this your self, but I would be hesitant. If it does indeed seal refrigerant in, you risk having it spray in your face -- this can freeze your corneas and blind you, and even safety glasses may not completely protect you.

I'd go fight with the shop and demand that they finish the job -- they should have noticed that there was nothing to connect the wire they took off to before they charged the system!

Peter

Piotr · #5 07-31-2002, 11:03 PM

Thanx, Peter (incidentally, my name is also Peter, but in Polish). Unfortunately, these guys mean well, but are really from the "backwoods" of Delaware i.e. if-I-look-at-it-i'll-probably-will-figure-it-out sorta guys. They try, but sometimes... well... Besides, they charge me only 1/2 of what certified MB guy does (the ONLY one in the northern Delaware), so I don't mind too much. I'm just ticked, because it's just a 10- minute job with the system discharged. Oh well, back to the garage we go...

190D22 · #6 07-31-2002, 11:39 PM

Half price or not they should correct their error free of charge and recharge the system free of charge as well. You took it in for proper repair and for the damn thing to work, it didn't work so therefore they didn't do their job.

Piotr · #7 08-02-2002, 10:58 PM

bad news. The compressor has to come out. (**^*&$^$%##@1

Well, we all learn on our mistakes, I guess... worse, phones were down, they could not contact me, so the car will be ready Tuesday. Double)((*&^*^%.

leathermang · #8 08-03-2002, 10:21 AM

Why did the compressor have to come out ?

JHZR2 · #9 08-03-2002, 03:45 PM

(off topic)

could you tell me more about this independent place that you take your car to? Are they a MB or european car specialist, or just a local garage? I live in Bear, and take my car to MB of wilmington for stuff that I dare not do myself, but Id love to find an independent around here to save some $$$...
Thanks

JMH

Piotr · #10 08-04-2002, 12:08 AM

My God!! You don't mean... DEALER, do you??? I called them once asking for service department. They told me nobody was there. I asked if they were an MB dealer and if they actually fixed MBs. They hung up on me.

For stuff that I cannot do myself and to diagnose problems I take it to Ezio's garage on Union street near the dealer. he is the only registered MB garage south of the PA border. He charges dealer labor ($91/hr) but has good mechanics and is really honest.

For little stuff I take it to the precision tune on Rt 301 just before Middletown. These guys are all Americann, but are willing to tackle any job, and don't mind putting my (internet) parts in the car. Example- Ezio quoted $1200 to fix the AC. even with all the problems, this job will cot me $600 from precision tune

leathermang · #11 08-04-2002, 03:44 AM

Why did the compressor have to come out ?

Piotr · #12 08-04-2002, 10:59 PM

The backwoods boys claim thay don't have enough space to replace the switch. they claim even with four mounting screws off, they still don't have space. I looked, and I disagree. But, with the 95F weather I want this thing done and over with. I just never thought that replacing an AC compressor will be such a hassle.

Piotr · #13 08-04-2002, 11:04 PM

JHZR2 - The independent guys (it's Precision Tune II- not affiliated with the others) will be tickled to death to work on your Chevy (they LOVE my wife's Stang). But, unless its something really simple, go to Ezio's (I live in Lea Eara Farms over the Canal and everybody here with an MB goes there) Auto Care . If you do, tell him that Mr. 190 Diesel sent you, and that I'm working on screwing up my car again, so he can fix it. A private joke.