Refilled my AC, now the electric fan is always full speed

[Turbo_Bimmer]

--> 4.8is, 2005: Electric fan on engine, no mechanical. <--

I had only cool air in the left vents and warm air in the right ones.

I hooked up a set of gauges, and found that the low side was only at 35psi whith the engine running and AC at MAX.

According to my chart, it should have been around 48-49 psi for the ambiant temperature of 30°C.
I filled the system with a can of R134A (12oz) and after one can, it was only at 45psi. So I connected another can, and went a bit more near 49psi.

While I was putting more refrigerant, the electric fan speed was gradually going faster and faster. When I disconnected my hoses, the fan was spinning at full speed.

I went for a ride, in the neighbourhood, then on highway, and the fan is always ON at full speed when the AC is ON. If I turn the AC OFF, the speed goes back to normal.

Is this a normal behavior? I find that noise very annoying.
It was not doing that before the refill.

Any 4.8is with working AC that can chime in ?

[Franksauto]

The thing about just adding cans is that you really never know how much is in the system. It could be undercharged which can do damage to the compressor or you could be overcharging it and could potentially damage several componants in the system. I did it that way for years in my shop and had good luck most of the time. When I finally got a machine is when I realized I was doing my customers a dis-service. The only real way to charge an ac system is to recover, vacuum to pull out all contimination, add oil (with uv dye) and charge to the recomended amount. It really does make all the diferance in the world. I will never do the can thing again unless its a temporary fix.

[Turbo_Bimmer]

Franksauto, I agree with you about adding refrigerant by weight being the accurate way of doing it. If I was starting with a repaired system that has been opened, I would go to a shop to have it done this way.

Since my system is operational, but only low on the refrigerant, I choose to do it myself using a set of good gauges.

Just to clarify, after the additional refrigerant, the system works A1, with cold air at every vents.
I'm just not used to ear the electric fan run at high speed all the time and I'm a bit afraid that the motor may fail or the control circuit overheat etc. Since this is the only fan I have on my engine, I don't want to loose it and overheat the engine.

Update:
This morning I hooked up the gauges again, and here are the numbers I got on the gauges: LOW side / HIGH side psi

38/175
35/225
32/270
32/300
32/270

ambiant temperature was 21°C and 77% humidity.

Air at the center vents was 45F

Take a look at the video I made. At a point (49s), you can ear the fan speed going faster.
00102 - YouTube

[SlickGT1]

I was sitting in my car yesterday with my baby asleep, waiting for the wife to come from a store. Good 10 min at idle with AC on. I came out to actually check the fan, I have never really heard it before. It was on. Couldn't say it was on high speed, but it was definitely always on.

[nebilex]

Turbo, I had a similar experience over the weekend while refilling my AC. I literally heard the fan start to spin faster and faster as I was adding more refrigerant, so I stopped. The car drives fine and i think the fan speed sounds normal now. I'll let you know if anything new develops.

[Turbo_Bimmer]

Slick, next time you drive the X, could you please check the fan speed with normal cooling, and then with setting to MAX. Thanks.

nebilex, does your X have a mechanical fan + electric? Does the fan sounds like a jet engine taking off like in my video? Let me know if there is something new. Thanks

[nebilex]

Originally Posted by Turbo_Bimmer

nebilex, does your X have a mechanical fan + electric? Does the fan sounds like a jet engine taking off like in my video? Let me know if there is something new. Thanks

I'm not sure what my X have. I have an 01 X5 3.0...I'll record a video of my X and send it to you so you can compare it.

[SlickGT1]

Will do Turbo. I'll check tonight.

And nebilex, has a 3.0 according to his sig. He has the clutch and aux fans. We only have the one electric fan.

[Turbo_Bimmer]

During the last two days, I paid more attention to the speed of the fan.
I found that it is not running full speed all the time. It depends of the amount of heat transported by the refregerant from the cabin to the condensor.

When the cabin temperature reaches the setpoint, the fan slows down since there is just a small quantity of heat to dissipate through the condensor.

I suppose that when my system was under filled, it was not as efficient as it is right now, so, very little heat was sent to the condensor so the fan didn't have to run at a higher speed to cool down the condensor.

So, I will assume that the high fan speed during the initial cooling of the cabin is normal.

Slick, did you have a chance to try you AC at MAX to see if the fan kicks in high speed?

[SlickGT1]

No not yet. Had to keep rocking the F-150, work and stuff. Will do tomorrow night. I'll run it max from start and update you with the behavior of the fan.