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Hi all,
Looking for expertise in A/C on the older 240s.
Last summer I converted the system to r134. I did do a proper conversion, flushing, oil change, new exp valve, orings, new dryer, and new high pressure line, vacuumed and charged while monitoring high/low pressures. The system was OK, held up well over the harsh winter, and still performs as it did last summer.
By "OK" I mean it cools nicely on the highway, but not well in traffic or not good ability to cool the interior in extreme heat/humidity or at idle (i.e . the vent temp is not too low but sorry no measurement to provide).
Charge amount is good, as verified by presusres at ambient temp. Compressor cycles as expected. I can;t recall ... but on the very hot day I had something like 40ish at low and 230 at high side. This was with approx 30 oz of r134.
When in traffic with A/C ON, the engine temp starts to slightly get too high. When I turn off the A/C, the engine cools down within 30-60 seconds.
Not a problem with heater control valve, I verified and it does completely close the coolant to the heater core. I have tried blasting the condenser with the garden hose, still similar performance.
Due to all these characteristics, one can deduce that the problem lies in :
1) the efficency of the evaporator;
2) a problem with the cooling of the condenser (accounting for trafic/highway difference).
I care not to tackle item 1) above. Therefore I would like to consider improving air performance to the condenser.
Question#1: How can I tell of the fan clutch is operating properly? Note the engine never overheats without A/C, cooling system recently flushed with new tstat (stock temp). Is the clutch supposed to tighten as temp increases?
Question#2: If I convert to an electric fan, should I add another fan in front of the condesner, to have one for the rad, and one for the condenser?
Question#3: Should I keep the stock fan (for rad cooling) and just add a fan on the condesner behind the grill for condenser cooling only, and wire that one to the A/C switch?
Question#4: Anyone tried doing such A/C performance mods?
Let me know, Thanks!
Greg Mustang
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