The cooling fan runs continually loud even at high RPMs?

Tiny
JAMESRVANYA
  • MEMBER
  • 2001 FORD EXPEDITION
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 243,000 MILES
When driving with the A/C on the cooling fan runs continually loud even at high RPMs. Turn the A/C off and the cooling fan works as it should. I replaced the radiator thermostat water pump lower radiator hose and coolant reservoir. The fan clutch is only about 6 months old the above reason is why I changed the fan clutch. A/C doesn't cool really well unless the truck is idling. A/C compressor was replaced about a years ago new dryer accum the whole works. Thank you for your help in advance. I am really stumped with this.
Friday, July 23rd, 2021 AT 5:32 PM

21 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good evening,

Can you give me the high and low side freon pressure readings while the engine is at 1,500 RPMs? I want to be sure the system is working correctly. You can rent a set of gauges at a parts store for this test.

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

I want to get the A/C working correctly before the cooling system.

https://www.2carpros.com/articles/how-an-engine-thermostat-works

https://www.2carpros.com/articles/replace-thermostat

Roy
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Friday, July 23rd, 2021 AT 6:10 PM
Tiny
JAMESRVANYA
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Okay, I'll have to go get the gauges I don't have them I'll rent them. What should the Low and High pressure be?
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Friday, July 23rd, 2021 AT 6:14 PM
Tiny
ASEMASTER6371
  • MECHANIC
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Depends on the outside temperature. Give me the readings and the outside temperature.

Roy
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Friday, July 23rd, 2021 AT 9:23 PM
Tiny
JAMESRVANYA
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I did get the gauges I will get the reading in the morning. Thank you
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Friday, July 23rd, 2021 AT 9:29 PM
Tiny
ASEMASTER6371
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Sounds like a plan.

Roy
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Friday, July 23rd, 2021 AT 9:31 PM
Tiny
JAMESRVANYA
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I went out this morning ambient 80F attached 77 PSI Low and 80 PSI High numbers are cold vehicle. Started vehicle ac on High MAX cold at idle 30 PSI Low and 255 PSI High. I increased idle to 1,500 RPMs constant 33 PSI Low and 300 PSI High. *FYI I have a shim that I use to keep the 1,500 RPMs idle so I can be at the front of the truck The fan comes in and the low side goes to 25 PSI and the compressor cycles pressure on the high side comes down to about 150 PSI. It appears to me that the High side pressure switch is not working. I don't know what the High side switch activates at. Would please give that information and this could be the problem. Maybe I'm off base. Please your experience will help me a lot.

Thank you,

James R Vanya
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Saturday, July 24th, 2021 AT 7:22 AM
Tiny
ASEMASTER6371
  • MECHANIC
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Okay, when the fan comes on, the pressure comes down to the correct pressure. The high side should be 2 times ambient temperature plus 15%. 25 when the fan comes on is good. It is a little low.

Both pressures are a little low. Do you have cold air coming out the vents?

The high side switch opens and turns off the compressor when the high side pressure exceeds 375 pounds.

Roy
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Saturday, July 24th, 2021 AT 7:28 AM
Tiny
JAMESRVANYA
  • MEMBER
  • 15 POSTS
Not really it gets about 66 or so idling driving it's about 70. Could the condenser be partially clogged causing the fan to engage more than it should? I have never had this fan run while driving down the road as it does now and the fan clutch is about a year old. My truck does not run hot at all. Perfect temperature no matter how hot it is outside.
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Saturday, July 24th, 2021 AT 8:14 AM
Tiny
JAMESRVANYA
  • MEMBER
  • 15 POSTS
Could low R134a cause the fan to run more?
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Saturday, July 24th, 2021 AT 8:15 AM
Tiny
JAMESRVANYA
  • MEMBER
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I bought the fan clutch at AutoZone. Could the activation temperature be wrong on this fan clutch? I am going to check on a Motorcraft fan clutch.
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Saturday, July 24th, 2021 AT 8:20 AM
Tiny
ASEMASTER6371
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To be honest, I think you are low in Freon. When the pressures come down, they are lower than they should be.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

The fan is doing fine. No need to worry about that.

Roy
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Saturday, July 24th, 2021 AT 9:00 AM
Tiny
JAMESRVANYA
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FYI, I just returned from a trip to the bank about 8 miles one way I have a thermometer in the vent it read 70F driving. When I was in line at the bank it went up to 74F on the way back It lowered to 62F. That's as cold as it will get. How much should I add what should the pressures be at 1500 when it working correctly? Should the compressor cycle on and off it the system is working correctly?
Thank you,

James
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Saturday, July 24th, 2021 AT 9:47 AM
Tiny
JAMESRVANYA
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Thank you for the great link I'm reading it now.
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Saturday, July 24th, 2021 AT 9:53 AM
Tiny
ASEMASTER6371
  • MECHANIC
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You need to recover what is in there first. You cannot tell the Freon level by pressure.

Evacuate the system for 45 minutes and then add the exact amount required.

Fluid Types
A/C Refrigerant. R-134a Refrigerant YN-19
Capacities
Capacity

Without Auxiliary Climate Control. 1.05 kg (37 oz)

With Auxiliary Climate Control. 1.78 kg (62 oz)

Roy
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Saturday, July 24th, 2021 AT 10:08 AM
Tiny
ASEMASTER6371
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Did you respond? I got an email but nothing came through.

Roy
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Saturday, July 24th, 2021 AT 12:19 PM
Tiny
ASEMASTER6371
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Still nothing, sorry.

Roy
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Saturday, July 24th, 2021 AT 1:04 PM
Tiny
JAMESRVANYA
  • MEMBER
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Okay, I replied using my Galaxy S20 and I guess you can't use a mobile device. Let's see if this works. I am going to take my truck and have the ac service as you suggested and when done I will update you with the results. I appreciate all of your help. Thank you James R Vanya
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Saturday, July 24th, 2021 AT 1:31 PM
Tiny
JAMESRVANYA
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FYI, when I replied with my cell and clicked the reply button the screen went blank and no message was above it like it is now replying from my laptop. Thanks again, James R Vanya
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Saturday, July 24th, 2021 AT 1:33 PM
Tiny
JAMESRVANYA
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I figure the 62 oz calculates to 3.875 can at 16 oz per can. My truck does have rear A/C so it's the 62 oz application.
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Saturday, July 24th, 2021 AT 1:35 PM
Tiny
JAMESRVANYA
  • MEMBER
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It will be Monday before I can have it serviced. Have a Great Weekend!
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Saturday, July 24th, 2021 AT 1:36 PM

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