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A/C evaporator ICES UP

boatmoter on Thu July 05, 2007 6:01 PM User is offline

Year: 93
Make: SATURN
Model: SL2
Engine Size: 1.9
Refrigerant Type: R-134-A
Ambient Temp: 96F.
Pressure Low: 33
Pressure High: 178
Country of Origin: United States

HI, if I run the blower on low or medium,about 15 minutes later the evaporater will ice up and will have no volume thru the vents untill I turn the compressor off and let the blower de ice it.. it has the recommended amount of freon,it has been installed by weight >> it takes about 3 minutes,on med. hi or hi to deice >> on med hi or hi it does not freeze.. >> have new compressor > dryer > tried (3)expansion blocks > changed the pressure switch from another saturn,still have the same problem..but this a/c system kicks butt when its not frozen.. any suggestions appriciated...

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Glenn //

Dougflas on Thu July 05, 2007 8:35 PM User is offline

So then assuming it works on high speed and I did not see an evap sensor in the schematic, I would venture to say that maybe the airflow thru the evap is low. Possible a dirty evap coil?

boatmoter on Thu July 05, 2007 9:49 PM User is offline

thanks.. I'll check that...

-------------------------
Glenn //

JJM on Fri July 06, 2007 12:54 AM User is offline

The compressor control valve is stuck or otherwise defective, and the compressor is not destroking... look at those pressure readings.

Replace the control valve. Also, your system is low on charge for 96F ambients.

Could also be the wobble plate is jammed, less likely, but also a possibilty. Unless you're versed in rebuilding compressors, best to replace it if that's the case. But replace the control valve first.

Note this cannot be done with the system under pressure; refrigerant must be recovered, and system must be evacuated and recharged to spec after repairs.

Joe

bohica2xo on Fri July 06, 2007 2:47 AM User is offline

Actually Joe I believe that refrigerant control valve is externally adjustable on the '93 SL2. There was a 1995 TSB on evaporator freeze-ups on that car.

It is a moot point however, since this was an R12 car from the factory. I would recomend putting 36 ounces of R12 back in it for proper performance...

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

JJM on Fri July 06, 2007 9:56 AM User is offline

Good catch Bohica - on both counts - that system was factory R-12 and the compressor control valve being adjustable. Damn you're good!

I knew the oddball compressors on these things weren't typical V5 units. And I did find that GM TSB: 95-T-48 issued in October 1995 exactly as you noted. Gotta love how GM loves to make things complicated though... like hooking up a Tech 1 just to maintain 2,000 RPM during the procedure. I guess holding the throttle open with a screwdriver is beneath them.

Joe

boatmoter on Sat July 07, 2007 5:12 PM User is offline

you say the expan. block is adjustable?? which direction should it be turned and which does it need to do,less hi side, or more hi side? I take it its going to be less pressure but I would like to hear it from you guys.. and to save time,where is the adjustment at on the block?

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Glenn //

JJM on Sat July 07, 2007 5:39 PM User is offline

You don't adjust the expansion block, there's an adjustment on the back of compressor. Only on www.ackits.com do you get this kind of valuable information:

GM TSB 95-T-48

What other A/C sites give you this kind of valuable information?

Please note it's absolutely imperative the initial charge is PERFECT before you attempt any adjustments - no shortcuts here.

Joe

bohica2xo on Sat July 07, 2007 5:43 PM User is offline

Hey Joe:

What is a PERFECT charge for a 134a conversion on a vehicle that the MFG. says should not be converted?

Better polish up your crystal ball... you know that will be the next question. LOL


B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

JJM on Sat July 07, 2007 5:50 PM User is offline

Crap! I don't know why R-134a is stuck in my head for this vehicle, when you've correctly pointed out it is indeed factory R-12.

Bottom line I suppose is to just get the low side pressure up enough by trial and error then - as best as possible.

Joe

boatmoter on Sun July 08, 2007 4:30 PM User is offline

Im waiting on a reply from the website you give me for more info on the adjustment,and I have a scale,I will weigh it. I'll let you guys know how it comes out..

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Glenn //

JJM on Mon July 09, 2007 12:31 PM User is offline

Quote
I'm waiting on a reply from the website you give me for more info on the adjustment

Do I have to click on the GM TSB 95-T-48 link for you???

*** CLICK HERE!!! ***

Bird is the word! (PENGUIN birds)

Joe




Edited: Mon July 09, 2007 at 12:35 PM by JJM

bohica2xo on Mon July 09, 2007 2:06 PM User is offline

Can't breathe.... LOL

Joe you are killing me here. I just had to clean a cup of coffee from my monitor.

Thanks for that one, I needed a laugh this morning.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

boatmoter on Mon July 09, 2007 8:50 PM User is offline

Hey guys.. theres directions on that there link.. if that link was there before then Duhh!!
Thanks guys.. if you guys need any tech info on fords.. I have the ford o.e. disc from 96 to 2001 for cars and trucks.. even covers body and jacking intructions. great evtm's too.reading the article on the saturn. it says to hook up a scanner to it,being a obd-1 I don't recall too much info from it with out useing a tech 2.. I only have access to a modis.

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Glenn //

JJM on Tue July 10, 2007 4:52 PM User is offline

I am totally friggen confused... can you see the three page TSB or not?

What do you mean "there are directions on that there link"? It's just a link to an Adobe PDF file. I assume you have the free Acrobat Reader installed, and if so the link should open a separate window with the TSB in Adobe PDF format.

The only reason for hooking up the Tech 1 scantool is to maintain engine RPM. You can accomplish the same thing with the old fashioned screwdriver wedged the throttle mech, pulling a vacuum hose (or hoses), or having someone sit inside with their foot on the gas... just keep it at 2,000 RPM during the procedure.

You can see all three pages of the TSB, correct??? If so, we're good to go. Let us know how you make out.

Joe

boatmoter on Tue July 10, 2007 9:04 PM User is offline

yes,I have already saved it to my computor.. Three pages.. Thanks.. I never seen this one before on mitchal on demand. and I see the scanner is just for the rpm increase.

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Glenn //

boatmoter on Tue July 10, 2007 9:06 PM User is offline

oh yeah.. I mean the procedure to repair the issue on the a/c. I'll be doing it this weekend.

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Glenn //

boatmoter on Mon August 20, 2007 7:34 PM User is offline

JOE, Did the Gm-tsb-95-48 procedure on my 93 saturn.. before I started the pressures were 48 and 255.
but puts out cold and ices the evap.. I evacuated and weighed in the 36oz. of R134-A , run for 5 min. at 2000 rpm, pressures were 19 and 200, turned adjustment clockwise in 1/8 increments and each time ran at 2000 rpm for 5 min. untill the low side reached 26.5, // highside 200, not very cold out the vents///
drove it and not satisfied.. shut engine off and put gauges on and opened the valves to equalize while I put the adjustment back where it was originaly, overcharged it again to the same readings I was getting before, which took 6 oz. and back to freezing me out again,purchased a thermostatic switch from tim and going to install that to cure the evap from iceing up..been overcharged like this for 3 years,hope it goes another 3.. puts a little more drag on the engine,but Im not sweating.. also plan to put a switch on the throttle body to open the clutch circuit at 50% to 100% throttle for getting into traffic and passing..
its a twin cam,but its not a nascar...

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Glenn //

Edited: Mon August 20, 2007 at 7:39 PM by boatmoter

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