This is on my friend's car. 1997 e320 (W210) with 145,000 miles. He was driving along and heard what he calls "a loud noise" followed by what he thought appeared to be smoke coming from under the hood. He immediately pulled over and turned the car off. He waited a bit, then started the car again. The A/C was now blowing warm air (was cold before the incident). So he turned the A/C off and has been driving without A/C for several days.

He brought it by my house today after work. With the car idling, I turned the A/C on and a second later heard an abnormal grinding noise followed by a belt squeal, and then nothing (noise stops). About a second later, it starts again; grinding noise, belt squeal, stops. And the cycle continues. I only let this go on for about 5 to 10 seconds and shut it off.

He's going out of town in a couple days and leaving the car with me at which point I'll be better able to diagnose the problem. I plan on hooking up the gauges as well as turning the clutch and hub to get a better feel for what's going on. But I'm betting it will need a new compressor and dryer. Should I just go ahead and order one from FastLane?

Also, any inside tips or tricks I should know? For instance, I know some of the earlier compressors tend to leave "black death" spread throughout the system - will I need to remove all the hoses and parts in order to flush? What about metal shavings - will a compressor failure send those circulating through the system? Also, what type of oil and how much should I add to the compressor when replacing?

Finally, in the event that I'm too busy to do this for him (I'm still deciding), how much should a job like this cost him at a dealer or reputable indy?

Thanks in advance to all the helpful people on this board!

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

BUMP. Also, I noticed the A/C compressor is not available on FastLane. I went ahead and did the quote request, but can anyone tell me where I can get a good OEM quality A/C compressor? Dealer or aftermarket?

Thanks everyone!

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

most definitely sounds like a/c compressor. if fastlane can't help you, try 1-888-392-0333. jensen auto. they sell remanufactured compressors. i purchased one and was very happy. i think i dealt with brian lowe.

__________________
"the simplest answer is usually the correct answer"

1991 190e, 2.6 (helga)
91,000 mi

Before replacing the compressor, you must break all a/c connections and THOROUGHLY flush all debris out of the system. When a compressor fails in this way it strews debris all through the system. If left in place, it will destroy the new compressor. Replacing the filter drier will not catch much of this stuff because it is between the condensor and evaporator. There will be plenty of stuff that the filter drier won't catch.

You also can get an aftermarket suction side filter to put in the line just before the compressor to help catch this compressor destroying junk.

Good luck,

Thanks for the feedback. And thanks for the reminder Larry, I must have read a dozen threads where you emphasized the need to flush, flush, and flush again, and then flush some more. I get the point and agree with your reasoning. I was thinking of using brake cleaner along with my compressor to blow it out - do you think that's a good idea?

As for the inline filter, could you recommend somewhere in the Dallas area where I can get one? Is that something they can install in the line in one day? Also, while I am a huge fan of the inline filter concept, how do you change it out when it gets "clogged" with debris? Will you have to open the system necessitating another receiver drier and evac/recharge?

So as it stands, I will have to call around and price a new or reman compressor along with a receiver drier. Any suggestions would be greatly appreciated. I plan on doing it Thursday or Friday evening and then going into this weekend, so I need to be able to get the parts within a day or two.

One last question while we're on this topic - I have a venturi-type vacuum pump that I have used in the past. I know, I know, the vane-type is the best, but venturi is what I have to work with. I recall viewing a chart not too long ago indicating that with the recent ambient temperatures of about 96 to 98 degrees I should be able to boil out any moisture even with the somewhat meager vacuum from the venturi pump, especially if I leave it on there for 1/2 to 1 hours. Any thoughts? Know of any places that will rent a vane pump?

Thanks again to everyone here!!!

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Oh, one other thing for the experts (I'm sure Larry knows the answer):

How do I flush the evaporator when it's buried inside the dash? Do I need to take the dash apart and remove the evap?

Also, where can I find a table like the one I talked about, temperature/pressure for R134A as well as vacuum effect on boiling water from a system?

Thanks.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

For parts, both Larry and I like McCain's in Richardson. It's on Floyd Circle, behind TI at Central & LBJ. 972-669-0669. I've found their prices competitive, no issues with quality. They have everything you might need, from parts to o-rings to refrigerant oil to refrigerant to gauge sets - you get the idea.

To flush an evap you need to remove the expansion valve. At that point you are left with just inlet and outlet tubing to the evap. Flush it both directions, and blow it out both directions. Unfortunately, I don't know where the expansion valve resides on a 210; never had to go looking for it...

I've got a collection of temp/pressure stuff buried away somewhere; will go looking for it and post later if I find anything of value.

- JimY

Thanks for the tip, that is very helpful. Would you by chance happen to know if they will sell or rent out a vane-type vacuum pump? I've got the venturi type and am thinking even with meager vacuum it might be effective with the extreme heat these last few days, especially if I leave the car idling while vacuuming. The extra heat will help boil out the moisture. I've also read of others tapping into the manifold vacuum while idling and using that to help vacuum moisture.

I've been eyeing the manifold gauges at Harbor Freight, so I'm covered there.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

I posted a chart showing the boiling point of water at various vacuum levels back in this thread: Review of my plans for the AC system, comments welcome Looks like you need to pull 28" of vacuum, given our current weather patterns.

Others have said that Autozone will lend you a vacuum pump. You put down a deposit equal to the cost of the pump ($200), then return it for a refund when done. Can't vouch for this deal, as I've never used it.

I'm sure McCain's has vacuum pumps for sale. Don't know what price range - he usually seems to have some deals laying around.

- JimY

The car was left with me earlier, and today after work I moved it into my garage. Just for kicks I hit the a/c button again (don't ask me why as I don't even know). Anyway, the a/c appeared to run for a few seconds. I *thought* I could hear the compressor kick on and it appeared that the clutch engaged and everything was spinning, albeit not very smoothly (at least "something" was going on under the hood). Then I heard the "grind" sound again and I quickly shut it off. Again, don't ask me why, but I did that a second time just for confirmation, then shut it off for good. When I got out of the car, there was a strong smell resembling burnt brake pads. Could this indicate that the clutch is not "grabbing" and is slipping after being engaged for a few seconds? I guess I'm hopeful that it's the clutch and not the actual compressor. I plan to loosen the belt tomorrow after work and attempt to spin both the outer clutch pulley and the center hub in order to determine resistance.

Oh, and by the way, I don't think the compressor would have stopped had I not turned the a/c off from the control panel. I thought there was a sensor that detected compressor speed differential and disengaged the clutch if any slippage or lockup was detected? This system didn't appear to behave that way. Is that further sign of some problem?

On a side note, I noticed that the headlights and dome light, etc. all have a very obvious "flicker" to them, almost as if they are going from bright to dim to bright to dim, etc. all in some sort of rapid cyclical fashion. It was very noticeable since it was night time and I had the car running in my garage with the lights pointing forward to the wall. Can I assume the alternator is not properly rectifying the voltage so that it is sending partial alternating current through the system? If so, could this have something to do with the possible a/c clutch problem i.e. the a/c clutch isn't getting the proper voltage so it won't hold for very long? That would be great if a new alternator or voltage regulator would solve the problem.

Any thoughts anyone?

Thanks in advance for your help!

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

What you smelled is likely the compressor clutch slipping. I expect the compressor is locked up. When you engage the a/c, the clutch activates, but just slips on the pulley, which continues turning.

These cars do not have the aggravating speed comparison circuit, so there is no instant cutout. I can't recall the details of what has replaced it - some type of heat sensitive circuit which eventually burns out. I think SteveB or MBDOC described it at some point in the past.

I fully expect the compressor needs to be changed out.

Can't address the flickering lights - might be time for a regulator?

- JimY

Well I crawled under and attempted to spin the front (center) portion of the compressor and it won't budge. I had my wife turn the a/c on while I watched, and it looks like the clutch tries to spin the compressor but can't. It doesn't even grind anymore, I just get the burning clutch smell. The grinding must have been the clutch trying to turn an already seized compressor as everyone guessed it probably would be.

I picked up the R134A gauge from Harbor Freight for $49.99, and it really is pretty nice! On a side note, I hooked up my venturi vacuum pump and it registered over 30" HG so I don't know exactly how accurate the gauge is. Either that or the gauge is accurate, but I'm only vacuuming the hose (as opposed to the much greater volume in the sealed a/c system). In any event, I think with the high 95 to 100 degree heat and an idling engine, this venturi vacuum pump should pull enough vacuum to boil out the moisture.

By the way, where is the high side port on the W210 E320? I looked all over and gave up, embarrassed - I can't find it!

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280