an AC question
Thread Starter
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i ain't rite
Joined: Mar 2005
Posts: 65,447
Likes: 5,517
From: Marlboro Mental Hospital.
an AC question
i posted this in the heating and cooling forum, and only got one response telling me my system needed to be properly evacuated and recharged by a professional after changing out the receiver drier, expansion valve, and orifice tube..
since i know how ac systems work, and do my own ac work, it is obvious i am not paying any attention to that post.
truck is an 02 superduty diesel.
low side pressure is 35 psi, high side is 174 at 82 degrees outside air temp.
dash vent temp is 53 degrees at idle on max air. bring idle up to 1500 and vent temp drops to 48-50 degrees.
take it out on the road at 45 mph and vent temp drops to 44-46 degrees. this sounds like a bad fan clutch, rite?
since i know how ac systems work, and do my own ac work, it is obvious i am not paying any attention to that post.
truck is an 02 superduty diesel.
low side pressure is 35 psi, high side is 174 at 82 degrees outside air temp.
dash vent temp is 53 degrees at idle on max air. bring idle up to 1500 and vent temp drops to 48-50 degrees.
take it out on the road at 45 mph and vent temp drops to 44-46 degrees. this sounds like a bad fan clutch, rite?
Senior User
Joined: Jul 2004
Posts: 150
Likes: 0
From: Nevada,
Im going with low refrigerant charge. 174 high side is actually low for a 134 system. And increasing the RPM increases compressor speed as well as fan speed. But if the fan was bad, both high and low pressures would be high at idle.
just my .02
Good Luck!
just my .02
Good Luck!
Postmaster
Joined: Apr 2006
Posts: 3,524
Likes: 2
From: CA Bay Area
I would ditto low refrigerant. How the pressure looks at 2000 rpm?
Than there is more to clima system that AC. I was surprised to find out that our SD have no heater valve and the core is hot all the time. Slight air leak on the mixer door, the door malfunction and the AC is no match for heater output.
I have valve installed.
Than there is more to clima system that AC. I was surprised to find out that our SD have no heater valve and the core is hot all the time. Slight air leak on the mixer door, the door malfunction and the AC is no match for heater output.
I have valve installed.
Senior User
Joined: Jul 2004
Posts: 150
Likes: 0
From: Nevada,
The book also states that you have to add refrgerant oil to the system for each part replaced. As well as evacuating the system to remove all moisture. both of these could also be contributing to your symptom. find the specs for the proper oil charge and do a complete evac and charge with oil. Is 42oz the minimum or maximum charge?? Out here in the dry desert we have to charge to minimum for best performance, Under minimum on some imports. If there is humidity, and cooler temps (under 100) you may have to put the charge to the maximum.
Thread Starter
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i ain't rite
Joined: Mar 2005
Posts: 65,447
Likes: 5,517
From: Marlboro Mental Hospital.
the system was evacuated and charged last year. it worked fine at close to the same pressures. last year i had 42 to 44 degrees at idle, and would get temps in the high 30's while driving.
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