A/C help needed
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New User
Joined: Oct 2015
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A/C help needed
Hi Guys, I dealt with this problem last year and couldn't figure it out. When I first start the truck (79 f150) a/c blows ice cold for as long as I don’t shut it off, went from Pittsburgh to Virginia with no issues last year. Shut the truck of and go into the store for 10 minutes and it only blows cool. I get full volume through the vents so I don't think its freezing, stuck my hand in there also and feel no ice. The system is a hybrid sort. The evaporator is 79, the comp, cond and dryer are from the donor truck, 1990 f350. Running a expansion valve from the 79 and a pressure switch from the 90. It does cycle on and off and the freeze thermostat is not wired in.
Any suggestion will help
Thanks,
Chet
Any suggestion will help
Thanks,
Chet
Laughing Gas
Joined: Nov 2013
Posts: 1,207
Likes: 60
From: S.E. Louisiana;so far USA
Hi Guys, I dealt with this problem last year and couldn't figure it out. When I first start the truck (79 f150) a/c blows ice cold for as long as I don’t shut it off, went from Pittsburgh to Virginia with no issues last year. Shut the truck of and go into the store for 10 minutes and it only blows cool. I get full volume through the vents so I don't think its freezing, stuck my hand in there also and feel no ice. The system is a hybrid sort. The evaporator is 79, the comp, cond and dryer are from the donor truck, 1990 f350. Running a expansion valve from the 79 and a pressure switch from the 90. It does cycle on and off and the freeze thermostat is not wired in.
Any suggestion will help
Thanks,
Chet
Any suggestion will help
Thanks,
Chet
FTE Legend
Joined: Nov 2015
Posts: 30,935
Likes: 4,123
From: Angier, NC
I had the same issue with my 02 Durango factory system. Yep first start of the day was fine till you shut it off unless off most of the day like work.
Also found if you were in town traffic stop n go, it could run warm too.
My fix was when the compressor blew up.
The shop doing the work said the evaporator was bad, crap inside it. They replaced it, compressor and the 2, front n rear, expansion valves and dryer and has been working better than when truck was new.
So if the evap was used you may want to replace it and the expansion valve maybe even the dryer.
Dave - - - -
Also found if you were in town traffic stop n go, it could run warm too.
My fix was when the compressor blew up.
The shop doing the work said the evaporator was bad, crap inside it. They replaced it, compressor and the 2, front n rear, expansion valves and dryer and has been working better than when truck was new.
So if the evap was used you may want to replace it and the expansion valve maybe even the dryer.
Dave - - - -
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New User
Joined: Oct 2015
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Thanks for the reply.
First the comp does run when the truck runs cool. The expansion valve and dryer receiver are new. I did clean out the evaporator and cond but they are original. Compressor also is used, perhaps I,ll start with a new comp and condenser as these are a lot easier to replace then the evaporator.
First the comp does run when the truck runs cool. The expansion valve and dryer receiver are new. I did clean out the evaporator and cond but they are original. Compressor also is used, perhaps I,ll start with a new comp and condenser as these are a lot easier to replace then the evaporator.
FTE Legend
Joined: Nov 2015
Posts: 30,935
Likes: 4,123
From: Angier, NC
Thing is if there is any junk in the system you are only going to push it into new parts turning them in to junk then too.
Flushing does not get it all out.
I know it hurts to have to replace it all but that is the best way to do it.
Dave - - - -
Flushing does not get it all out.
I know it hurts to have to replace it all but that is the best way to do it.
Dave - - - -
Cargo Master
Joined: Nov 2009
Posts: 2,364
Likes: 117
From: starship enterprise
there are a lot of old systems out there still running well. I would ask do you have a manifold set? If not look into getting one bought or borrowed. Hook up when running cold and look, hook up again when running warmer, and log pressure differences. Do this before opening system up. I have seen farm tractors do this, it is often from too much oil, the system only holds so much, and by adding a bunch of oil, the system capacity is diminished by volume of oil. If you installed used parts, the compressor might have had oil in it, the other parts might have oil, = too much oil. A weak compressor or a weak valve could sure cause this, works ok on start up then once everything is hot, clearances go too far out. Good luck.
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