A/C blows hot randomly
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3rd Gear
Joined: Sep 2024
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A/C blows hot randomly
Howdy everyone!
I have a 2002 Ford F-350 Super Duty 7.3L diesel and i have a problem with the AC
It blows nice and strong and cold say in the morning, in fact sometimes i turn it down because i'll get cold, but in the afternoons it seems the compressor kicks off. The compressor is almost brand new, a friend who has a great reputation as a mechanic installed it, purchased from RockAuto. Less than 2 years ago. Sometimes it shuts off when I accelerate (the blower starts blowing hot) but other times its just random. Is the compressor already bad again?
Also, i noticed the control panel for the Climate, when i adjust settings like switching the AC off or on, i hear a hissing noise like pressure being released when i turn the **** (not sure where it's coming from). This also isn't consistent, so i haven't been able to recreate it as it doesnt happen all the time. Does the control panel just need replaced? I live in West Texas, is the AC just being taxed meaning I need an additional AC fan? would appreciate any help, thx!
I have a 2002 Ford F-350 Super Duty 7.3L diesel and i have a problem with the AC
It blows nice and strong and cold say in the morning, in fact sometimes i turn it down because i'll get cold, but in the afternoons it seems the compressor kicks off. The compressor is almost brand new, a friend who has a great reputation as a mechanic installed it, purchased from RockAuto. Less than 2 years ago. Sometimes it shuts off when I accelerate (the blower starts blowing hot) but other times its just random. Is the compressor already bad again?
Also, i noticed the control panel for the Climate, when i adjust settings like switching the AC off or on, i hear a hissing noise like pressure being released when i turn the **** (not sure where it's coming from). This also isn't consistent, so i haven't been able to recreate it as it doesnt happen all the time. Does the control panel just need replaced? I live in West Texas, is the AC just being taxed meaning I need an additional AC fan? would appreciate any help, thx!
Fleet Mechanic
Joined: Aug 2011
Posts: 1,570
Likes: 258
When the AC doesn’t want to work, pop the hood and see if the compressor clutch is spinning or not, it is possible that the clutch gap is to far away, when cold the electromagnet is strong enough to pull the clutch in but when hot it isn’t as strong and may not be able to pull the clutch in.
Fleet Mechanic
Joined: Aug 2011
Posts: 1,570
Likes: 258
It is possible the gap was set wrong at the factory, could of been just on the edge of spec and now that it’s worn a bit it can’t engage when hot, spec looks to be 0.013”-0.035”, I would shoot for around 0.020” if you have to adjust it, you can try pushing on the clutch with a piece of wood while it’s running and see if it engages.
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
You'd certainly *hope* so but *hope* ain't much of a troubleshooting plan. Do the check and report results.
Fleet Mechanic
Joined: Nov 2011
Posts: 1,825
Likes: 43
From: Land of Taxes
Or the blend door actuator(s) is leaking, disconnected or the line to it is cracked. If you have dual zone replace both. Fun job.
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Fleet Owner
Joined: Mar 2012
Posts: 26,106
Likes: 4,148
From: Near Cal. Avenue
Most likely the heater blend door is sticking. Put a gauge on the Compressor and test the Pressure of the AC. If it is good, you have an indash problem.
If the pressure is low you have a problem with control or Compressor.
Use the standard AC Pressure gauge set and test it when hot.
Reading the pressure is always the first test. Sure look/test fuse and relay.
Since your problem only happen on a warm days / afternoons cause it may need a can of Refrig. U may have a leak? Maybe a sealer will get you thru till next time.
On those 90 degree trips home RPMs will mess up The AC system too. Ur problem is most likely expensive if a can of "Refrig" doesn't help! But cooler weather / fall
is starting to set in and maybe next spring will work well for the fix.
If the pressure is low you have a problem with control or Compressor.
Use the standard AC Pressure gauge set and test it when hot.
Reading the pressure is always the first test. Sure look/test fuse and relay.
Since your problem only happen on a warm days / afternoons cause it may need a can of Refrig. U may have a leak? Maybe a sealer will get you thru till next time.
On those 90 degree trips home RPMs will mess up The AC system too. Ur problem is most likely expensive if a can of "Refrig" doesn't help! But cooler weather / fall
is starting to set in and maybe next spring will work well for the fix.
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Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
Blend door actuators have nothing to do with compressor clutch operation.
Fleet Mechanic
Joined: Nov 2011
Posts: 1,825
Likes: 43
From: Land of Taxes
When reading the OPs #1 post the first thing that jumped out to me was blend door malfunction. I have seen it 100x and it was not mentioned.
You are right to check the high/low pressures first. Watch the clutch cycle. If its doing all of this right then go toward the control system...blend doors.
Hopefully the mechanic that sucked down the system changed the filter & dryer too?
Trash in the filter can cause this intermittent hot/cold problem which will mask itself as low or high pressure.
.
Many a shade tree mechanic overcharge a system and trash the compressor because they didn't start simple... line pressure & controls.
Also verify:
- clutch air gap
- evap & condenser are clean
- engine clutch fan is engaging/disengaging when it should
- belt tentioner is working and the belts not slipping....thou you'd think one would hear see and smell that.
Remanufactured anything is a large crap-shoot today.
Realedk (lol) why haven't you visited your ace mechanic??
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