AC trouble
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Mountain Pass
Joined: Feb 2004
Posts: 243
Likes: 13
From: Mass.
AC trouble
My 2004 with 5.4L Lariat is struggling to keep me cool. The AC works fine on mild days but when it gets into the upper 80s it works for about 10 mins then goes warm. If I shut down the AC for about 5-10 mins. it begins cooling again.
I first tried a retail charging kit with no improvement. Then I had the system drained and refilled with die to look for leaks, but neither had any immediate impact. So it is not a leak, but something else failing.
What are the next best troubleshooting steps for an AC system?
I first tried a retail charging kit with no improvement. Then I had the system drained and refilled with die to look for leaks, but neither had any immediate impact. So it is not a leak, but something else failing.
What are the next best troubleshooting steps for an AC system?
Hotshot
Joined: Jul 2005
Posts: 11,931
Likes: 180
you need to know the HI side pressure and the LO side pressure of the system and the ambient temp that day. The most common cause of not cooling is low R134 charge. You said you have added gas, but what was the pressure. Then they removed the gas and put in a die... WHY ? Proper pressure is the No 1 cause... that being said, you could have excessive clutch clearance and the clutch would not stay engaged as needed... Look at the clutch when system is "ON"... does the compressor stay engage "MOST" of the time ? If not, then you have low pressure, or clutch problems.
Thread Starter
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Mountain Pass
Joined: Feb 2004
Posts: 243
Likes: 13
From: Mass.
you need to know the HI side pressure and the LO side pressure of the system and the ambient temp that day. The most common cause of not cooling is low R134 charge. You said you have added gas, but what was the pressure. Then they removed the gas and put in a die... WHY ? Proper pressure is the No 1 cause... that being said, you could have excessive clutch clearance and the clutch would not stay engaged as needed... Look at the clutch when system is "ON"... does the compressor stay engage "MOST" of the time ? If not, then you have low pressure, or clutch problems.
The clutch shows no evidence of slipping. It engages when on and disengages when off.
Fleet Mechanic
Joined: Apr 2016
Posts: 1,653
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I would have them replace orifice tube at one point .They are cheap
Could be getting clogged it has screens in it to get wear junk out of sytem.
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Hotshot
Joined: Jul 2005
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which is why you FIRST need the HI and LO side pressures... to figure out WHAT the problem is.
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Thread Starter
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Mountain Pass
Joined: Feb 2004
Posts: 243
Likes: 13
From: Mass.
Yeah that is what I am thinking. They said the pressures were good. I did a youtube search for videos on the sensor change and could not find one, so it can't be that common. There are however several for the Lincoln MKZ and Ford Fusion.
Hotshot
Joined: Jul 2005
Posts: 11,931
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if the pressures are good, and the clutch is engaged, and the fan is running.......... it has to get cool....
another part of the system is the BLEND DOOR... This is a motor operated door that sets by the heater core and ac coil and BLENDS the discharge air to get the temp you want... it is possible the door is broken on the hinge and flopping to the HOT side if you cant control the temp. Check the temp of the ac hoses/ tubes under the hood to verify that you have a COLD line working properly.. I will post a link to a blend door drawing.
another part of the system is the BLEND DOOR... This is a motor operated door that sets by the heater core and ac coil and BLENDS the discharge air to get the temp you want... it is possible the door is broken on the hinge and flopping to the HOT side if you cant control the temp. Check the temp of the ac hoses/ tubes under the hood to verify that you have a COLD line working properly.. I will post a link to a blend door drawing.
Hotshot
Joined: Jul 2005
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