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Ac drier-should I replace

1K views 13 replies 9 participants last post by  Ears 
#1 ·
I bought a NEW ac drier from a friend along with other parts.
My Ac blows between 43 and 45 currently.
Do you think there is any advantage to use this new part ?
I do not know what the driers LIFE expectancy is ---do they go bad or routinely need replacement or should I keep it on the shelf for future use along with a new compressor I bought?
 
#4 ·
I would think 43 - 45F out the vents is pretty much as good as its going to get.
Are you using R12 or R134?
 
#7 · (Edited)
I too have a 1983 380SL.
I replaced my Compressor with the new design more efficient aluminum
Compressor, replaced the Drier, and charged it with Enviro-Safe freon.
Right after all this, at highway speed I got 24F, and 39F at idle.

My pressures were 26 Low, and 150 High at idle.
Conversely, my 560SL with its original Denso Compressor and Drier is 41 Low and 225 High
and doesn't cool as well.

I need to check it now that its been 3 years.

Still, yours at 43F with R134 is not bad at all.

And what's really important is what is the differential between the outside Air Temperature
and the cool air coming out of the Vents.
 

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#6 ·
I agree with others as long as the suction and discharge pressures are within acceptable range. The drier primarily removes moisture/water from the circulating refrigerant system. It can also trap other debris. A little moisture is not so bad. The moisture can affect cooling if in sufficient quantity but mostly can generate a damaging acidic condition. If the system has never been opened to the atmosphere for more than a very brief period, no significant leaks and was properly evacuated after any work, then the drier should be fine. Usually the drier is only replaced after a compressor or other significant component change. But on occasion they can plug up which would result in abnormal pressures.
 
#8 ·
Usually you don't want the evaporator much below 32deg F or it will ice up, reducing air flow and therefore interior cooling. Occasionally drier dessicant bags will break open, releasing dessicant ganules into the system, clogging the expansion valve or orifice tube. This produces very poor cooling, there may be frosting just downstream from the expansion valve because of very low pressures there.
 
#11 ·
Took my 380SL out for a spin this morning.
My digital thermometer measured 49F out the AC vents with
the outside temperature measured as 90F. 41F differential.
 
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