I bought a stem remover from autozone yeterday, specifically designed to remove those schrader valve cores. Well there is nothing to remove. its not a normal schrader valve. The auzone AC expert guy came out to look andhe said that its the first time he sees a non-removable schrader valve core.

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'95 E300 Diesel, 264,000 Miles. [Sold it]

The EPA looks the other way regarding the leaky evaporator issue, don't they.

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2012 E350
2006 Callaway SC560

Arthur, I just topped up my AC system with 1 can (12 oz) of R134. Most of the bubbles are gone, but fan still didn't come on. Then again the ambient temperature is only 18 C (65F). So its probably too cold for the preasure switch trigger them. I'll wait for a warmer day.

Yesterday I went to Autozone and bought from them a tool to remove AC schrader valve cores ($.99). Went outside to try it, (I though at least that I can try tightening it) and found out that there is nothing to tighten or to remove. These are not normal schrader valves. The AC knowledgabe guy at autozone didn't believe me and came out to look. He said that its the first time that he sees a non removable schrader valve core.

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'95 E300 Diesel, 264,000 Miles. [Sold it]

[QUOTE=pberku;1505489]Arthur, I just topped up my AC system with 1 can (12 oz) of R134. Most of the bubbles are gone, but fan still didn't come on. Then again the ambient temperature is only 18 C (65F). So its probably to cold. I'll wait for a warmer day.>>

OK. Now you prob just need some ambient temp.
As you can see, there is a very fine line between the requirements for aux fans to get triggered ..the reason for this is they do not want to have to use the fans until there is a High Thermal Load condition.. that's all they are there for .. as an aux aid to the system when needed. I am confident you will prob find them to trigger on a hot day .specially at idle in the same spot for a few minutes...
I do want to say that the correct way to really check this out is with gauges to monitor the high side , but for the diy guys here, I know they do not have the proper equipment , so I do post with that consideration in my BarnYard techniques ..but they work.
Anyway, this fine line for fan cut-in is so fine that many times one can add as little a 2 ounches of refrigerant and get the high side back to fan cut-in specs..but the ambients needs to be there before doing so...[some guys put cardboard in front of condensor the simulate that condition, but they know what they are looking for , so i don't recommend that for you.].wait for a hot day..you will see.

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Yes , it is true..they are factory sealed into the line...
The reason I mentioned for you to give yours a quick jab is b.c when a tech is removing the test lines and tap from a valve , it does not get that quick Snap action to seal it..it is quite common.. the reasoning behind this is that the sealing off of the valve is actually done by the pressure from inside the system pushing the valve closed ..by snapping it shut, it seems to immediately seal from it's seating better than if it is slowly released , which is what happens when the charge line tool is taken off/removed. I always snap them shut.. even a few little taps on the side will help seat one that is not completely closed...and then make sure the cap is tight , even though the caps funtion is a dirt cap, not a pressure seal..

Arthur, you have been of great help with this post. One last question. Am I ok with one working auxiliary fan, or do I absolutely need both. I just changed one of them about 1 months ago, and now the other one went. This car is driving me broke.

Again Thanks

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]

Being up North, you will probably get away with it...
My recommendation would be for you to put a parallel resistor mod on the High Fan sensor to drop that cut-in down to 100c or so..[ from 107] ..that only cost about $1 or $2 to do and that would give you the protection if you did run into a hot summer for a few days. Realize that this is a backdoor approach ..the correct way would be to have both fans funtioning. If I were down to a single fan, I would also be sure to clean out both the radiator and condenser fins for max flow/efficiency..
Remember . the fans are most important when the vehicle is not moving ..down a highway, they are not even needed..so , if you are stuck in a City somewhere , I would fix that other fan before it fixes you....
I use that 100C resistor modification for coolant sensing down here in Fl. but never had to in NH.. as a matter of fact, the reason I have the experience with low fan cut-ins and ambient temps is b/c I came from NH and unlike here in Fla, there were many a day my a/c did not call for aux fan just b/c of the Northern climate .
Many guys down here never experience a no a/c fan as normal operation b/c it is usually high enough ambients to be called for all the time. ..so they just do not see that condition.......

Same deal with the high fan .. we always see post where the posters complaint is he never sees a high fan in operation..[this is usually after he has read some post about someone having a legit complaint about his fan circuit, by the way]....well, the question is " Does you temp ever get up to 107C.. if not , don't expect your fan to come on..it may NEVER come on...
it doesn't HAVE TO come on. it is not being Called For , it may not come on as long as you own this car... it is an AUX device ....now go back to your room....

PBERKU.

I see you're from Montreal.
Where about are you in Mtl?

If you were already at AutoZone, why didn't you rent the gauges there? I rented gauges from AutoZone when my personal set were out on loan, so I know they have them. It won't cost you a dime. Charging by sight glass is guessing at best - you really need to know actual pressures before you can further diagnose your high pressure switch problem.

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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've always thought that using the sight glass was perfectly adequate. Else why would it be there.

What the system wants is a steady stream of liquid refrigerant coming from the drier, thru the sight glass to the evaporator. The sight glass gives you that info.

Yes, if you are wildly overcharged or undercharged the sight glass can be misleading.

The reason systems with accumulators don't have sight glasses is because there are always some bubbles in those systems. Hence, the sight glass would be misleading in that case and the gauges would be the only way to go.

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2012 E350
2006 Callaway SC560

I have on 3 or 4 occasions "thought" that system charge was correct using the indications from the sight glass, then shortly thereafter discovered that they were way off after hooking up my manifold gauges. In researching both at this site and elsewhere, I have found that I am not alone, and most techs now say the PROPER way to charge is by weight. This is now the way I do it - put the correct weight in, and forget the rest. I still of course do this through the gauges.

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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 agree that the best way is probably to charge by weight.

However, you must start with an empty system to do that. Most people here do not have the means to evacuate their systems.

Not meaning to be difficult, but in your first post you said "you really need to know actual pressures." In your next post you said to charge by weight.

They are not the same.

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2012 E350
2006 Callaway SC560

>>However, you must start with an empty system to do that. Most people here do not have the means to evacuate their systems.
>>

Many do not realise that some of these answers we give are NOT the best bet way to do things, but they are more geared to the poor diyer guy who can get to charge his own car w/o having state of the art equipment.
Yeah, you can use some common sense and a sight glass. and yeah, retrieving codes with a Radio Shack $2 led is not to be compared to a HHT Benz Scanner...etc . , etc.... but be reminded that many a car get fixed with simple tricks here and that makes up 1/2 of this group..
It's easy to jump on backyard technique as being crap, but there are many a car that get fixed here with them...give me a little info, a few jumper wires and some common tools , and you would be quite amazed at how fast I have fixed many a mechanical/electrical problem, be it a car, tractor, computer, or what have you...
There is a litle Mcquever [ or whatever his name was]in all of us..
Info is the rule...

Okay, you guys are right - everything is relative. For clarification, let me state that there are several ways to determine state of charge. Some are simply more accurate than others. In order, from most accurate to least:

1. Charge by proper weight with gauges attached and thermometer in vent
2. Gauges, maybe with thermometer
3. Sight glass

Again, I say that the sight glass does not tell the whole picture. What if there is an obstruction somewhere in the line causing the pressures to be excessively high? You wouldn't see that without gauges. And if your high pressure switch is defective, you may just be damaging something.

Really, I don't think my suggestion was way out of line. Like I said, Autozone has the gauges for free rental, putting their use well within the scope of the average DIY'er - me included (I am not a pro). With free gauges, there is no reason NOT to hook them up and provide a reading which can only help diagnose the problem further. Now if they have tried to get gauges and can't, that's another story. But telling them to just go by the sight glass when there is a perfectly viable alternative is misguidance in my opinion. Kind of like telling them to measure tire pressure by the bulge of the sidewall - it is somewhat accurate, but why not hook up a tire gauge especially if one is freely available?

__________________
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

Arthur, You were right. The ambient temperature today was 20C (68F). I turned the AC on, let the engine idle, and after a few minutes my single working fan came on. So that's good. I guess I was low on R134.

I do however want to charge the system properly by my Indi, but am paranoid of him attaching anything to my high pressure side schrader valve, for fear it will start leaking again. Can a vacuum and recharge (by weight) be done to the system through the low pressure connection only? Will additional oil be needed?

__________________
'95 E300 Diesel, 264,000 Miles. [Sold it]

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BS.. what do you think a sight glass is for ??
I have been doing refrigeration for years and years...There is no mis-guidance here.
As a matter of fact , the misguidance on this post was right from the get-go He was told he needed a new hose for an unseated high side valve..but a quick tap to seat of the valve fixed that right off, like they always do..then he was told he needed a high pressure sw ..well, the old sight glass and a little info from this Forum took care off that, too..[ I have seen only two bad switches in all time ..one had a leak and the other was shorted closed , resulting in constant fan]
Any working A/C Tech will tell you on a "no low fan complaint" that if the fan works when the sw is jumpered , the most likely problem is low refrigerant..not the sw. Take note that I said "Most Likely"..
So, we solved this little birds nest of problems quite easily with some common sense and very little $$$$. So forget about Misguidance ..if anything..Excellent guidance would be more appropriate..
Topping off a system with the aid of the sight-glass is perfectly acceptable .
..and if you re-read any of my post , you will see that I mention gauges as being the best bet, so I am not giving eyesight preference..I am just giving good info of the variable ways it can be done considering ones circumstances..Not Misguidance my friend, that's for sure..