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  #241  
Old 06-23-2006, 07:47 AM
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http://www.aircondition.com/tech/questions/19/What-are-the-Benifits-of-Leak-Testing-with-Nitrogen%3F

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  #242  
Old 06-23-2006, 10:14 AM
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Quote:
Originally Posted by James L
a 40 degree drop or difference between ambient and vent temp is normal and anything more is asking for alot out of any a/c. measure vent temps/ambient in any central home hvac unit for an example.

all this talk about 38 degree vent temps...the fsm says 48 degree vent temps and anything lower than 41-42 they say to check the evap temp sensor for proper function so as not to freeze up or flood the evap. the ets is supposed to signal the comp when evap temp gets too low to cut off. the fsm also says at 104 ambient 68 vent temp is normal (of course humidity plays into this also). on low fan the vent temps drop cause evap has chance to build up. at high fan speeds air is moving accross faster and it is playing catch up.
Laws of Physics are difficult to get around but it seems that fish strories, fuel mileage, and vent temps often manage to do so.

There is a direct correlation between low side pressure and evaporator temperature. Check the vapor/pressure chart and read about subcool and superheat. At any given pressure there is a corresponding temperature at which the refrigerant changes from a liquid to a gas.

Higher outside temps mean higher condenser temps and higher pressures. Higher pressures mean higher evaporator temps.

I checked my vent temps yesterday against the outside air temps (94F). On high fan it ran 48-54. On low fan it hit 45 mometarily but I think that was just due to lag when I changed the fan setting. This was not comfortable, I wanted to turn it down, I was cold.

My car had been parked in the shade all day and it rained a little in the afternoon, cooling the car even more. When the sun shines on your car all day the temps inside are probably 120-130. The pavement is probably just as hot. You can't expect the AC to catch up very quickly.

I have had thoughts of running a total loss irrigation system for my condenser in extreme high heat. Instead we are packing to go back to Maine after the 4th.

Last edited by TwitchKitty; 06-23-2006 at 10:21 AM.
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  #243  
Old 06-23-2006, 10:17 AM
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Quote:
Originally Posted by TwitchKitty
I have had thoughts of running a total loss irrigation system for my condenser in extreme high heat. Instead we are packing to go back to Maine after the 4th.
Pump the water from the evaporator up there.
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  #244  
Old 06-23-2006, 11:09 AM
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Quote:
Originally Posted by TwitchKitty
Laws of Physics are difficult to get around but it seems that fish strories, fuel mileage, and vent temps often manage to do so.
That's the truth. Six months ago, I had 20 degree air coming out of my vents. In the "EC" mode, no less. Claims of low vent temps are meaningless when not accompanied by ambient temperatures. And even then, they are subject to the "fish story" phenomenon.
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  #245  
Old 06-23-2006, 02:45 PM
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Leatherman

The old york compressor, like in my W115, you say has an oil sump? If so, is there a drain and filler area? Where would this be? Also, I've heard these yorks a a lot more heavy duty than the delco R4 in the W123. Dealer told me these old yorks have no problem running R134 if I ever wanted to go that route. Any truth to any of this?
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  #246  
Old 06-24-2006, 08:11 AM
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Kyle, One of the advantages to manufacturers of using the Delco pancake compressor is that it can be mounted in any position...
The York can only be mounted in two positions...
The MB AC manual for our cars shows how to make a bent DIPSTICK for measureing that sump oil... it is a rod with markings on both ends... one end for horizontal mounting and one upright...
It is my impression also that that York P piston is much stronger than our Delcos... whether that comes from always having the oil available from the sump I don't know... but certainly with anyone using other than R12 the oil movement is suspect for the Delco.
The disadvantage is that they are much rougher due to the weight and movement of those two pistons together rather than four smaller pistons with the movement spread out over the full rotation. It is also my impression that the York takes more HP to run...
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  #247  
Old 06-24-2006, 07:06 PM
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I am looking at a complete rebuild of my system. I am not going to get a liscence so that I can buy the r12. So would this york you're mentioning work in place of my delco?

If I am going to have to use the r134a, I want a compressor that I wont have to change out every couple of years.
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  #248  
Old 06-25-2006, 02:21 AM
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The York is usually mounted top front right on the MB's that I have seen it on...
It has a heavy mounting weldment.
If you are good enough at fabricating and hose building to be able to mount the York then you could easily mount one of the more standard type round compressors which are the size and shape of starter motor... this would provide the extra strength without the excess size and vibrations associated with the York... in other words... there are valid reasons why everyone switched over from the York 2 piston type to 4-6 piston swash plate style compressors....these later styles have oil sumps but fit along the engine with less hassle than the York style.
Changing out the compressor style would be 1000 times more work than taking the OPEN book $20 epa test so you could just buy and use R-12.
Do you feel you could not pass the online test ?
If you change to the other style compressor I hope you will take good pictures and notes and post them... a lot of people would like to do that.
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  #249  
Old 06-25-2006, 10:56 AM
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Quote:
Originally Posted by leathermang
Do you feel you could not pass the online test ?
Sure I could, it's the principal of the issue.

I shouldnt even own a $1000 benz if i cant pass the test. Otherwise, I'ld better be extremely well off to afford to have a shop do everything for me.

One other question, What are the compatibility issues of R12 and R134a? is it that the Lubricants react? Do the refrigerants react with the others lubricant? I understand the Legal and ethical reason (I have read this entire thread) but what keeps one from flushing an R12 or R134a system, to then use Synthetic lubricant and the refrigerant of choice? It seems that if the synthetic is non reactant with either refrigerant, just increasing the air flow across the condenser and using a parallel flow condenser would allow one to use R134a with cooler results (pun intended).

I know its like re-engineering the system slightly but it might be a better alternative to using "ozone depleting" (BS) R12 or using the toxic sludge R134a, depending on how you feel about it.
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  #250  
Old 06-25-2006, 11:23 AM
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Yes, the lubricants react ( as far as I have read ).... seem to make a nice glob.

My control c-control-v keys are not working so I can not paste to here...and it wont let me use apostrophies either.. brings up search feature at bottom of page in Firefox.

Essentially there is nothing wrong with the course of action you describe. Take out all the R-12 lube, put in a good R134a lube , upgrade either fan or condensor or both ( and clean the fins on the evaporator inside your car )...
IF you use a synthetic which the R-134a will take around the system to keep your Delco lubed ( given its dependence on the oil movement due to lack of sump ) then ALL you have to worry about is the HIGHER head pressures... which MAY only affect worn Delco compressors.
Installing something like the Nippon or GM compressor would be a nice upgrade...

Since it appears that you do not consider the R-12 Ozone depleting why dont you just follow the rules about its use and have a car which is cool and comfortable at the least amount of work and money ?

If wanting to re engineer stuff was objectionable I would have been thrown out of several forums already.
Most things sold in this world have a balance between perfect and cost..which the manufacturer decides the line on... where I live I need a little more cooling than they did in Germany... and things get old... that is the time to put the extra into re engineering.. when you are already going to have the hassle and expense of replacing something anyway...
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  #251  
Old 06-25-2006, 01:10 PM
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I have had the same problems with Firefox. I have found that if I double click the field in which i want to insert text, after the FF search bar come up, I am able it input the text in the field that I want to use, instead of the FF search bar. It is aggrevating to me, too.

On the R12, I believe that R12 may in fact destroy ozone molecules (or whatever we can derive to simulate them) but our releases are no comparison to the amount of ozone created by the various methods found in nature. I would be more willing to believe that the reduction of the earths' magnetic field is more a culprit than the miniscule amount of cfc's(when compared to the volume of the earths total atmosphere) released by the automotive industry.

I also have it on good authority that the Air Force used R12 as a parts cleaner for sensitive aircraft parts in open hangers, long after the EPA ban. My friend who personally did this, believes that it still practiced, as it was considered the best option. If it was so bad, they would have been the first to stop using it, right?

I wont use 12 because I believe that thier should be no Govenmental ban on such an item. Agreeing to participate in the process make me nausious, as it is really more or less just another way to control a free people through environmental legislation. Without giving a lecture on government, I will just say that this issue is only one of many caused by the same cancer of the current eco-economic-world-government philosiphy that is preached as necessary and sadly enough being recieved as truth by the masses.

So as long as refrigerants dont react with each other I will use synthetic lube and rebuilt parts, simply to lower the total cost of a complete system rebuild.
Maybe later down the line(no pun intended) when that rebuilt comp goes out I will fab up a weldment to change compressors.


Thanks for your advice and knowledge.
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  #252  
Old 06-25-2006, 01:44 PM
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I agree with your second paragraph... many things are larger contributors of several of the world climate problems including Cow Emissions... and I am not kidding..

However, with regards to R-12 , since our old cars were made to run with it, I prefer to think about the larger problems while cold air is blowing in my face from the center vent. LOL

All my other vehicles use R134a and have plenty cold air conditioning. If I had the time and money to put a GM 6 piston compressor and P-Flow condensor into my 240 I would use R-134a myself.

In the past it was usually R-11 which was used for flushing ... but individuals can mess up... or declare an emergency ( some times just in their own mind ) with regards to military missions ...and stuff like that happen.
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  #253  
Old 06-26-2006, 04:48 PM
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still smells...how to proceed...??

Well, now I've read some of the "threads" about Mold. And, now I've done some priliminary search on products which may be used to de-contaminate a moldy evaporator. The methods described (or not) remain a "tad" ambiquous(sp?) in my opinion. My 1992 W124 does not have a drain problem....I have two water trails on the ground from two sources at approximately the same location directly below the evaporator area.

The aroma smell is still a frequent situation so I'm thinking about a product and a procedure which might give good results. I see some "Freshener Kits"...which include hoses and spray cans with special chemicals (high priced) used to treat the evaporator from outside the airvents.

ref: http://www.airsept.com/PRs/ACOSCEstaterPR_082405.doc

Should a reader have any experience with these or similar products please advise

Thanks

ron_of_orange 1:50 pdt
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  #254  
Old 06-26-2006, 05:15 PM
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Ron, perhaps you missed my posts on this.. I suggest you try CHEAP and simple first.. get a can of Lysol antiseptic aerosol.... turn on your AC and find where it is taking air into the evaporator.... and spray into that area...
Also a good chance of fixing the situation is a bottle of FEBREEZ....
Also turn your dials to heat during this to be sure the heater fins are sprayed...
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  #255  
Old 06-26-2006, 11:53 PM
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Hey if all else fails try a weak bleach water solution, each day of the week for one week. No so much that it drips, unless you plan on having a white towel down to protect the carpet.

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