Constantly Running Radiator Fan

[Nick Green]

Hi Guys

I've read all the threads about constantly running coolant systems, however non of them matches my case exactly.

I've got a 2016 mustang ecoboost. No tune, In the past it had some problems with A/C radiator - it leaked freon and became empty by the time, I discovered that suddenly the fan started working all the time from the moment of start (regardless outside temp). It was obvious recharging A/C with freon would solve the problem - but the fan still continues to run all the time after I filled up the A/C system with freon and checked that it does not leak any more. Also an interesting fact - when I unplug A/C system socket( I do not know what to call it) which is on the left of the radiator piping, the system runs normally, the fans only turn on when the engine is heated.

Can anyone help???

Thanks

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[TexasRebel]

Bad Evap core.

 

[NoVaGT]

You know you need to add oil for the air-conditioning system, right?

I keep noticing folks re-charge their system, I'm just hoping they use refrigerant that has the oil in it.

 

[Nick Green]

Bad Evap core.

Thanks !!!

Do you have an idea where I can change it? i do not have an insurance any more

 

[Nick Green]

You know you need to add oil for the air-conditioning system, right?

I keep noticing folks re-charge their system, I'm just hoping they use refrigerant that has the oil in it.

Yep, I made sure he charged oil which was specified for the system, so that's not the cause.

As I've read main cause of such problems is freon pressure in A/C system, the interesting thing is the fan worked constantly even when the A/C system was empty of freon so had no pressure and after I added the freon, it only starts working properly when I unplug the A/C system from the pipe

 

[TexasRebel]

Yep, I made sure he charged oil which was specified for the system, so that's not the cause.

As I've read main cause of such problems is freon pressure in A/C system, the interesting thing is the fan worked constantly even when the A/C system was empty of freon so had no pressure and after I added the freon, it only starts working properly when I unplug the A/C system from the pipe

The system isn't empty. It's charged just enough to put pressure against the blocked evap core. If you have access to OBD2 data, look at the pressures.

As far as replacing the evap core, you have to remove the dashboard. The dealership replaced mine.

 

[Nick Green]

That will be a real headache though What if I do not if the problem, how much will the MPG affected and will it have any other bad effects?

Thanks

 

[sloppymax]

The system isn't empty. It's charged just enough to put pressure against the blocked evap core. If you have access to OBD2 data, look at the pressures.

As far as replacing the evap core, you have to remove the dashboard. The dealership replaced mine.

What is the range of pressure that is acceptable? I see that it will vary based on ambient temp but I cannot locate what is out of range.

 

[scorpion143]

Hi Nick,
I seem to be having the same problem you are describing on my 2017 GT. Did you find the reason?

My ac is blowing hot air, and the radiator fans running from the start. Freyon pressure is normal according to Midas guy. I changed the brakes before it started doing that, but it shouldn't be related!

Any help is appreciated.

 

[TexasRebel]

Hi Nick,
I seem to be having the same problem you are describing on my 2017 GT. Did you find the reason?

My ac is blowing hot air, and the radiator fans running from the start. Freyon pressure is normal according to Midas guy. I changed the brakes before it started doing that, but it shouldn't be related!

Any help is appreciated.

Make him define "normal".
Is he using a high & low side gauge?
Is he using a gauge for R1234YF?

Is a person who marginally understands a braking system qualified to diagnose HVAC?

 

[scorpion143]

He used the high/low gauges. I didn't see the readings, but he said there is pressure in the system. My car uses R134A. I am pretty sure he is qualified, I don't think Midas would have employed him otherwise.

Another thing he noticed, When i start the a/c, the compressor clutch engages, but disconnects rightaway, so he concluded it's electrical, and didn't recommend just flushing and recharging the system. In that case, i think i am better off to the dealer, so he didn't do further testing.

 

[TexasRebel]

My guess. The evap core collapsed (common, see above).

When the compressor kicks on it almost instantly over-pressures the high side (400+ psi was my reading) and it kicks off again. The high pressure is related to a high temperature so the fans kick on as a safety even though there's nothing for them to do. You won't be able to "flush the system." It's blocked.

2018 switched to R1234YF, did he know there's a difference between S550 year models?

 

[K4fxd]

it only starts working properly when I unplug the A/C system from the pipe

Do you think the high pressure switch could be bad? Try checking it. If you don't know how go to an A/C shop, not Midas

He used the high/low gauges.

If he used high low gauges...

When i start the a/c, the compressor clutch engages, but disconnects rightaway,

Cannot read high side if the clutch won't stay engaged.

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