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a/c in wheel loader cool not cold

ctkiteboarding on Sat August 03, 2013 3:38 PM User is offline

Year: 2005
Make: case
Model: 321d
Engine Size: 4cy
Refrigerant Type: 134
Ambient Temp: 85
Pressure Low: 27
Pressure High: 230
Country of Origin: United States

struggling with this loader, system was blowing warm, oem calls for 38.8 oz, did a 24 oz recharge (ambient 85* ) to get the low to 30 and the hi to 215, still the vent temp was 58*, cleaned the evaporator and a new cab filter, then brought it to the local garage ,he put it on the machine (coolaire) and pulled it down , he said i had exactly 38 oz in ,an hr later 27 and 225 but still only 56* at the vent.

so decided to change the receiver dryer and the expansion valve as these where inexpensive and original , had the guy evac the 134 and took it home , replaced the parts re -checked the evaporator to be sure it was clean , put the vacuum on it to -30 for 40 minutes , held this vacuum for 30 minutes, added 12 oz ( first can with dye) at a time ,compressor kicked in, got to 36oz and had 30 low and 240 high ( ambient 82*), did my best to add just a tad more as to not over charge it , still 56* at the vent, compressor has never cycled, just stays on when the a/c switch is on and turns off if the switch is turned off, new belt is tight but is squeals for about 20 seconds when machine is first started then its fine my guess is pulley need replacement, any ideas? help?

mk378 on Sat August 03, 2013 9:37 PM User is offline

Fully charged and 27 on the low side, the air should be colder than that. Check for reheating from the heater or freeze-up of the evaporator.

Off-road machines tend to clog up the fins of the condenser / oil cooler / radiator stack. The first thing to go will be A/C performance, long before it gets bad enough to cause the engine to overheat.

ctkiteboarding on Sat August 03, 2013 9:48 PM User is offline

i put a shut off inline to stop any heat into the cab... il look into the radiator clog thing makes sense. ..... lots of water dripping off the machine from a/c drain also ran cold water from a hose over the evaporator ( in cab radiator) to see if the pressures would drop and vent temps but nothing changed

Edited: Sun August 04, 2013 at 9:37 AM by ctkiteboarding

ctkiteboarding on Sun August 04, 2013 6:20 PM User is offline

ok stack was /is clean , ambient temp was 77* connected the gauges 78low 85high, vent temp reads 80*

start machine up, a/c on high ,windows open ,at idle ,low side 22 high 200 vent reads 60*

set engine at 1300 rpm, low side 27 high 260 vent temp lowers to 52*

decided to spray stack with hose just for data low side 18 high 157 vent temp stays at 52*

drain is constantly dripping water


Porkchop on Tue August 20, 2013 10:15 PM User is offline

I was wondering if you'd figured out what your problem is yet? I have a very similar problem and readings as you.

Dougflas on Tue August 20, 2013 10:31 PM User is offline

Possibly the heat load is too high for your AC system. Did it ever cool better?

Leggie on Tue August 20, 2013 10:36 PM User is offline

Originally posted by: ctkiteboarding
i put a shut off inline to stop any heat into the cab...
I would not do this. Some designs control heat by an inline valve on the heater core, but designs that only control by the means of air handler may use the heater core as part of coolant bypass which allows coolant to circulate within the system when the thermostat is closed and it may lead to hot spots that can damage the engine.

If you must, use a plastic nipple to bypass the heater core, or use two tees and two valves if you want to have the ability to bypass/use without opening the cooling system.

Constantly dripping water indicates your system is closed system is working well and your pressures are reasonable. Large amount of water means a significant portion of capacity is allocated to latent capacity.

if ambient is 85 and humidity is 85% and it is cooling the outside air, what you describe is perfectly normal. If the plastic and foam parts intended to keep out air from engine compartment is leaky, it would further aggravate the complaint you're describing since the A/C takes in humid air that's been heated up by the engine.

If you have it in recirculation mode, check to make sure that air flaps are not off track or jammed.

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