2003 MB E320 W210 R/D missing

[erubin]

Hi, First time here and hoping to get some advice.

I just picked up a super clean MB E320 with 120k miles. Fixed a few simple things like the leaking driver door lock actuator and radio amp. Now ready to take on the AC. I've done AC work on my cars in the past and own manifold set, vacuum pump, and hand tools.

The car was maintained beautifully except that it was involved in a small accident a few years ago and the RD was removed and the two pipe going to it were cut off and not capped.

I will make this assumption: AC was working well before the accident. Car was owned by a wealthy man in Palm Springs but with his dementia he could no longer drive and the car remained mostly parked for several years. I've been driving the car daily since I bought it for $3,500 4 weeks ago and all is well.

I have ordered a new RD, the RD temperature sensor and pressure sensor, the hose going from the RD to the condenser and the hose from the RD to the expansion valve. That will take care of the missing/damaged parts.

My question: Bolt it all back together, with new lubed o-rings, run vacuum pump for an hour, let sit overnight and run vacuum pump another hour. Load R134 and see how it goes?

Or am i surely going to have contaminated oil in the compressor that needs to be drained and refilled? If so must I remove the compressor and drain and refill?

[bohica2xo]

That car has the direct drive compressor. No clutch. An electrically operated control valve de-strokes the pistons wen cooling is not needed.

So it has been turning since the day the R/D was cut out of the system. Hard to say what the compressor condition is at this point.

There is a shear ring on all of those compressors. If it seized, the shear ring lets the pulley break away from the compressor shaft so the belt does not break and you can still drive the car.

I would not bet on that compressor. Was the condenser damaged in the accident too?

[JohnHere]

Adding to what has already been said, I would worry about the oil as well. I don't know what type of oil MB originally put in it. If it was double-end-capped PAG, I would be somewhat less concerned. If it was the single-end-capped variety, that oil type is much more hygroscopic, meaning that it absorbed at least some moisture from the air that entered the system. Not knowing which type it has, I would just clean-out all the old oil.

My question: Bolt it all back together, with new lubed o-rings, run vacuum pump for an hour, let sit overnight and run vacuum pump another hour. Load R134 and see how it goes?

You could do as you suggest and take a chance that it will work. But you should also be prepared to do the job over—replacing the compressor, condenser, receiver/dryer (again), and flushing the rest of the components—if it doesn't.

My references for your car list 35 ounces net weight of R-134a and 7.0 fluid ounces of PAG-46.

[tony1963]

The factory engineered the compressor to run constantly. MB found that compressors sitting idle for long periods contributed to lack of lubrication and failure.

A control valve controls the angle of the swash plate and percentage of capacity of the unit. As a result of this technology, compressor failures are very rare.

You likely have a code in the system for low refrigerant which will inhibit the compressor from working until cleared. You can disconnect the battery until the 2024 election and the code will still be there. It must be cleared.

As a licensed dealer for 20 years, I bought a lot of these vehicles that were low on refrigerant only to find the code in the system for low refrigerant. We would recover the remaining charge, install a new receiver/drier, add oil and refrigerant, then cash in on the vehicle.

I'm not retired in Florida, thanks to a very generous business and will gladly share my knowledge.

[erubin]

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The condenser is not damaged. Not sure what kind of accident would lead to what I'm looking at...the receiver dryer is like torn out. The aluminum pipe part of the hoses near the RD are broken off as though it was in an accident. The open ends are relatively protected under the hood but are not capped from atmosphere.

I should mention that my car is a 2002 and not a 2003, oops. I can spin the nose of the compressor by hand with the belt attached. So that means I have a clutch on my compressor. So if that's the case (and its not a sheared ring) I can assume the compressor is not constantly running and sucking in atmospheric air through the busted pipes. Check out the clutch equipped compressor photo and description my vendor shows for my car. BTW, my vendor shows a clutch on the 2003 model as well.

I could be game to drop and drain the compressor. Then what? flush it? slosh/spin it around with a solvent and dump it out a few times? or just drain and add new oil or don't bother removing it, just give it a shot of oil when it comes time to charge with r134. I really don't want to start pricing out a replacement compressor likely over $300.

The AC system has been open to atmosphere for a few years. Not sure from one of the comments if MB used different compressor oils and if that matters cause one type might be more hygroscopic than another type. I always evacuate the air out of an opened system with my little 2.5cfm pump believing that most/all the moisture is boiling out. But will atmospheric moisture likely already lead to unreversible acidity and corrosion in the compressor? And what about the bit of residual oil sitting in the condenser and evap. I don't like the idea of messing with the exp valve and flushing out the evap. And on top of that taking out the condenser to either replace it or at least to flush it "hors du corps".

I'm generally fine w/out AC by opening my windows and cursing a bit about the weather for a few weeks/months in the summer. And no efficient windshield defrosting on humid nights. Fixing or installing my cars' AC provides me with a luxury but not a need. The time it takes to fix it and for a slightly less important reason, the component costs often leads me to give up this creature comfort. The truth though is that I'm sitting on $175 of parts (the RD and the sensors on it and two new hoses) so I'm going to do at least something.

[JohnHere]

The condenser is not damaged. Not sure what kind of accident would lead to what I'm looking at...the receiver dryer is like torn out. The aluminum pipe part of the hoses near the RD are broken off as though it was in an accident. The open ends are relatively protected under the hood but are not capped from atmosphere.

Someone before you ripped out the R/D and lines for unknown reasons and just left the lines hanging. Now we have to determine the best way to get the system back into operation.

I can spin the nose of the compressor by hand with the belt attached. So that means I have a clutch on my compressor.

From what I've been able to determine, both direct-drive and clutch-equipped compressors were installed on these cars when new. To be sure which one you have, look closely at the wiring that goes to your compressor. Both types of compressors will appear essentially the same except that on the direct-drive compressor, the wiring from the controller goes to the back of the compressor and to the control valve instead of to the front of the compressor as on the clutch-equipped unit.

So if that's the case (and its not a sheared ring) I can assume the compressor is not constantly running and sucking in atmospheric air through the busted pipes.

That is correct. But the system is still open to the atmosphere.

I could be game to drop and drain the compressor. Then what? flush it? slosh/spin it around with a solvent and dump it out a few times? or just drain and add new oil or don't bother removing it, just give it a shot of oil when it comes time to charge with r134. I really don't want to start pricing out a replacement compressor likely over $300.

I suggest removing and flushing the compressor, but don't use any kind of solvent for that purpose. Use PAG-46, either DEC-PAG (check with the site's sponsor), or SEC-PAG. The procedure is to drain whatever oil is in there now, refill with new oil, rotate the mainshaft by hand about a dozen times (using a socket wrench if necessary), and repeat three or four times or until the oil comes out clean.

The AC system has been open to atmosphere for a few years. Not sure from one of the comments if MB used different compressor oils and if that matters cause one type might be more hygroscopic than another type.

If you can get the double-end-capped PAG oil (DEC-PAG), I would use that instead of the single-end-capped variety (SEC-PAG), the former being much less hygroscopic than the latter.

I always evacuate the air out of an opened system with my little 2.5cfm pump believing that most/all the moisture is boiling out. But will atmospheric moisture likely already lead to unreversible acidity and corrosion in the compressor? And what about the bit of residual oil sitting in the condenser and evap. I don't like the idea of messing with the exp valve and flushing out the evap. And on top of that taking out the condenser to either replace it or at least to flush it "hors du corps".

Evacuate down to at least 29.9 In.Hg. (Inches of Mercury) for at least one hour and preferably longer. To look for internal corrosion, check inside one or more of the lines that you take off with the aid of a strong light, looking for signs of corrosion. Hopefully, you won't find any. Flushing-out the other components with an approved solvent will take care of removing the old, contaminated oil.

I'm generally fine w/out AC by opening my windows and cursing a bit about the weather for a few weeks/months in the summer. And no efficient windshield defrosting on humid nights. Fixing or installing my cars' AC provides me with a luxury but not a need. The time it takes to fix it and for a slightly less important reason, the component costs often leads me to give up this creature comfort. The truth though is that I'm sitting on $175 of parts (the RD and the sensors on it and two new hoses) so I'm going to do at least something.

Most people consider A/C in their vehicles a necessity in today's world
Since you have the parts on hand, I would go ahead and make the repairs necessary to get the system going again.

[erubin]

Thank you John. Here are photos of the compressor. You can see that the wire goes to the middle but when I look up the Denso number it says clutch.

[erubin]

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above.jpg

Here is a view from beneath the car with missing RD. You can see some damaged metal with a few sloppy welds. Amazingly its the only sign of damage. The radiator support is perfect and factory original and the fender looks original with no paint overspray anywhere to be found. Its as though the damage only destroyed the RD and the car frame holding it. The second photo is taken from above. The electrical connector for the RD mounted temperature switch is intact but the RD mounted Blade type; 3-prong electrical connector is missing. I do se two sets of wires dangling in there, one is a green and a brown wire and the other severed wire pair is red/white and blue/brown stripped. Maybe I need to keep looking for the pressure switch 3-wire if it's not these?

[erubin]

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[erubin]

You wrote "I suggest removing and flushing the compressor, but don't use any kind of solvent for that purpose. Use PAG-46". How do I flush with PAG-46. That is the oil not the flush. Maybe you are suggesting not to use a flushing agent in the compressor but rather fill and drain with Pag-46 oil a few times to allow it to carry out some of the residual stuff.

"Flushing-out the other components with an approved solvent will take care of removing the old, contaminated oil." Can I skip that for the evap and the condenser? Assuming I see no corrosion in any of the pipes? It's hard to flush out completly the solvent when the condenser and evap are in the car. I really dont look forward to removing them from the car.