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Old 04-11-2007, 01:30 PM
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dannym dannym is offline
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Join Date: Oct 2004
Location: Deltona, Florida
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Quote:
Originally Posted by 1981_300sd View Post
My 82 240d needs an ac recharge - at first had 5 psi low side. Had already been converted to r134. So I picked up some refrigerant, started the car, jumped the compressor,
Why on earth would you jump out the compressor? It would have started on it's own as soon as the pressures came up.
Quote:
Originally Posted by 1981_300sd View Post
......So I get in the car, and now have cold AC.......
That is meaningless without knowing the temperature of the discharge air.
Quote:
Originally Posted by 1981_300sd View Post
My 2 part question is, should the pressures change that much by revving the engine? And since I have no tachometer on my car, can I just assume when I hit 1500 rpm and be safe at 35 PSI?
What's the temperature on your chart at this pressure? What temperature does water freeze at? Are you running the risk of making your evaporator a big ice block at this pressure???
Quote:
Originally Posted by 1981_300sd View Post
Details of the system:

Ambient Temperature is 85 degrees - my chart shows that I should have a 30-40 PSI low side charge at that temperature.
Your not comparing apples to apples here. The outside temperature has nothing to do with the discharge temperature inside the car. It would help a lot if you knew what that temperature was.
Quote:
Originally Posted by 1981_300sd View Post
My car reads:

About to die 45 PSI
Revved up to what I assume is 1500 RPM is 35-36 PSI
Revving the engine to higher RPM's goes down to 20-25 PSI
AC off completly shoots up to 100-110 PSI

Thanks for the feedback.
It sounds to me like your undercharged but you can't really tell without knowing the head pressure and discharge air temp inside the car.

Also be warned that if you leaked refrigerant you leaked oil too. At this point you don't have any idea how much oil you have in the system.

You also know you have a leak and you did nothing to find and fix it.

There's a right way and a wrong way to do this. The right way would be to find the leak and fix it. Then flush out the system and put a known amount of oil and refrigerant in.

Danny
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