Ac questions!
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Fleet Mechanic
Joined: Sep 2011
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From: Albuquerque
Ac questions!
Ac just quit completely, blowing hot air , I put some dye in it and see the dye all over the high side , went to change out the hose assembly from the back of the compressor, started busting things loose and there seems to be a lot of pressure still in the system?? It that normal? Holding some pressure just not enough to operate?
Logistics Pro
Joined: Aug 2009
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From: Arizona
Ac just quit completely, blowing hot air , I put some dye in it and see the dye all over the high side , went to change out the hose assembly from the back of the compressor, started busting things loose and there seems to be a lot of pressure still in the system?? It that normal? Holding some pressure just not enough to operate?
PS I sent you a PM about I-40 road conditions West of ABQ.....
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Fleet Mechanic
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From: Albuquerque
Ok working on the diagnosis, i just hot wire the compressor , the clutch engaged, again i put a can of dye in the system and for it all over the high side, i picked up a compressor and the lines , time to get it done, got a trip to lubbock i need to take the end of next week I sure don't want to do that drive without ac!
Logistics Pro
Joined: Aug 2009
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From: Arizona
Ok working on the diagnosis, i just hot wire the compressor , the clutch engaged, again i put a can of dye in the system and for it all over the high side, i picked up a compressor and the lines , time to get it done, got a trip to lubbock i need to take the end of next week I sure don't want to do that drive without ac!
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Oh yeah, mine doesn't blow cool at all right now unless it's cold soaked from sitting overnight...it's plugged up with either shavings or oil (or both), but there is still enough pressure in there to be dangerous. Resting pressures on both sides with the system off can be up in the 90-110 psi range depending on how hot the engine bay is. I've made the mistake of poking at one of the schrader valves with a screw driver...luckily had eye protection on.
Fleet Owner
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Fleet Mechanic
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From: Los Angeles, Ca.
Oh yeah, mine doesn't blow cool at all right now unless it's cold soaked from sitting overnight...it's plugged up with either shavings or oil (or both), but there is still enough pressure in there to be dangerous. Resting pressures on both sides with the system off can be up in the 90-110 psi range depending on how hot the engine bay is. I've made the mistake of poking at one of the schrader valves with a screw driver...luckily had eye protection on.
I've had a few where the compressor clutch only worked when cold, re-shimming to reduce the air gap cured them. As the clutch wears and the clearance (air gap) gets bigger it gets harder for the magnet to pull it closed. Since electrical resistance goes up with temperature, they can manage to work cold, then stop working as they heat up.
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Being clogged up is fairly uncommon, being low on refrigerant is much more common. Running it with gauges hooked up will tell.
I've had a few where the compressor clutch only worked when cold, re-shimming to reduce the air gap cured them. As the clutch wears and the clearance (air gap) gets bigger it gets harder for the magnet to pull it closed. Since electrical resistance goes up with temperature, they can manage to work cold, then stop working as they heat up.
I've had a few where the compressor clutch only worked when cold, re-shimming to reduce the air gap cured them. As the clutch wears and the clearance (air gap) gets bigger it gets harder for the magnet to pull it closed. Since electrical resistance goes up with temperature, they can manage to work cold, then stop working as they heat up.
2nd Gear
Joined: Mar 2008
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I’ve hooked gauges up and have observed its behavior a couple times now at different temps just idling in the driveway. Watched the high side pressure creep all the way up to almost 450 psi before shutting it down…guess rules out the pressure relief valve because it didn’t leak at all. It’s either got shavings from the old compressor going bad, or way-way too much oil in there from the Ford dealer putting back together wrong, or possibly even both. The clutch and compressor assembly is a new Motorcraft unit with probably only a couple hours of run time on it. Shop drew it down and put 2.5 lbs back in it and it still puked out the pressure relief valve with the engine bay hot, so the pressures are just too damn high for whatever reason when the engine is hot and cooling goes nonexistent. Does still work and blow cold on a cold start in the am, so I am leaning more towards too much oil trying to shove its way through the orifice tube causing pressure to spike.
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Fairly certain so, but I really wish now I hadn't let them touch it. Bad experience, bill was too high, and who knows what they did or didn't do.
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Mine is doing the same thing. Just replaced the entire system last year and started to have this problem. I was tired of chasing the issue so I replaced all but the lines and evaporator but flushed them well. Unfortunately I’m still having the same issue. So I must have an airflow issue. Now I’m leaning towards a clogged up radiator, I know the fan clutch is good.
2nd Gear
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would it be enough to raise the pressure enough to have it exhaust out of the relief valve?