A/C compressor/fan question

[Qsilver7]

Originally Posted by kevinkay

...for some reason it is still my "wild ass guess" that the issue is the front fan, it did not go on all today during the test unless being 50 degrees didn't warrant the fan coming on? ...

In light of using your gauges and discovering that the pressure is low...I'm not sure why you keep giving the aux fan the evil eye.

I don't normally suggest this...but since you have gauges and have fiddled around with the low & high side valves and it doesn't sound like you evacuated to the atmosphere ...you could try one of those R134a refill kits that have oil & leak sealer stuff in it...follow the directions as printed on the can (or paperwork that comes with it)...and see if that gets you through the summer. If it doesn't or the problem comes back a month or so down the road...then you'll know that you have a major leak in the system that needs to be repaired and can't be taken care of by a simple refill kit w/sealer.

And perhaps the information below will help you understand how the aux fan works so that you won't be so suspicious of its operation.

[kevinkay]

THANK YOU.
no I did not evacuate to atmosphere.

I think I might be on to something.....does the dash temp display have any control over a/c air?
Today was warmer, tested pressure
dash said outside temp was 60
low side was 22 and high side went from 190 then aux fan would go on and bring high side down to 150 fan would shut off - it would again rise up to 190 - click fan on, over and over
air seemed cool but not super cold as it used to be.
HERE is the thing, it is actually 70 degrees outside today and I had thought the dash temp has been acting a little weird past week.

I don't think my valves are leaking, I think i was mistaking the "pop" when I took the manifold off the car confusing it with pressure when removing the cap.
I might have screwed up yesterdays low reading on the hight side by not opening the port valve on the manifold completely - I think yesterday as soon as I saw the needle jump I stopped opening.

SO...if the car thinks ambient temp is 60 then my low pressure is good, high pressure fluctuates between range and high

If dash temp has no bearing and ambient temp is 70 then my low side is low - I need a charge? and high side again fluctuates between range and high.

IF my fan would stay on that would keep the high pressure within correct range - so I am still giving it the evil eye....

pressure readings with the car off- low 49, high side 135.

THANK YOU!!!

[upallnight]

If you have any software such as INPA or BMW Scanner 1.4 or even torque for android you can see what temp the DME sees.

[kevinkay]

Yes, I have INPA. Thanks, I will check it out.

Is it unusual for the fluctuation in high pressure with the aux fan going on and off?

[upallnight]

Originally Posted by kevinkay

Yes, I have INPA. Thanks, I will check it out.

Is it unusual for the fluctuation in high pressure with the aux fan going on and off?

If the fan didn't come on, the high pressure sensor will kick in and shut down the compressor. When the fan comes on, is the compressor still engage? The aux fan is there to lower the temperature of the refrigerant in the condenser. By lowering the temp of the refrigerant it also lowers the refrigerant pressure.

[kevinkay]

Tried using INPA, found "air intake temperature" but it was 95.45 celsius which is like 200 degrees fahrenheit, so i must be looking at the wrong temp, this must be heated air into the engine.

Yes the clutch still spins when the aux fan is on or off.

63 degree day and still getting low side at 22-25, and fluctuation with the high side with the fan on or off.

I am all ready to give it a charge as the more I am reading the more I believe that is my issue. I just want to catch a warmer day so the fan stays on and the ambient temp is with in range of the charts I am reading, most of them start at 65 degrees. Chart says at 65 degrees low side should be 25-35, didn't think I am too far off - but read in BMW a little low makes a big difference??

[kevinkay]

Finally a day I could work on it, 72 degrees outside, had 2 digital thermostats plus the car saying 72. Car warmed up, A/C on high, aux fan running, clutch spinning.

according to the charts at 70 degrees low side should be 35-40, high at 145-160.

I was going to shoot for a low side of 40 (figuring it was a little warmer than 70). When I let the coolant flow into the low side the meter jumped high quick - I got scared, shut it down - pressure stabilized at around the 30, then I opened it slowly, I knew coolant was flowing the can got cold and low side rose to 35 and high was at 205.
It would not take any more, no rise on the low side above 35.
My A/C is blowing cold, I am happy with the results

my system is not acting according to the charts, low side is on the low side and high side is higher than the charts. But I am 3 days into a working A/C. Maybe not a permeant fix as I may have a leek but if I had to add a little every summer season - no big deal. (don't tell the EPA)

[upallnight]

Originally Posted by kevinkay

Finally a day I could work on it, 72 degrees outside, had 2 digital thermostats plus the car saying 72. Car warmed up, A/C on high, aux fan running, clutch spinning.

according to the charts at 70 degrees low side should be 35-40, high at 145-160.

I was going to shoot for a low side of 40 (figuring it was a little warmer than 70). When I let the coolant flow into the low side the meter jumped high quick - I got scared, shut it down - pressure stabilized at around the 30, then I opened it slowly, I knew coolant was flowing the can got cold and low side rose to 35 and high was at 205.
It would not take any more, no rise on the low side above 35.
My A/C is blowing cold, I am happy with the results

my system is not acting according to the charts, low side is on the low side and high side is higher than the charts. But I am 3 days into a working A/C. Maybe not a permeant fix as I may have a leek but if I had to add a little every summer season - no big deal. (don't tell the EPA)

I'm sure someone from the NSA has already flagged this thread and notified the appropriate party at EPA..

[Qsilver7]

Originally Posted by kevinkay

...My A/C is blowing cold, I am happy with the results... I am 3 days into a working A/C. Maybe not a permeant fix as I may have a leek but if I had to add a little every summer season - no big deal. (don't tell the EPA)

...thanks for the update...at least you're not sweating it out for now. Hopefully you'll have cool air for at least the rest of the summer.

[kevinkay]

So while I got your attention......Can someone educate me on why my system has a low side reading of 35 and a high side reading of 205 at 70 degree ambient temp and is working perfect although this is imcomsistant with the standard pressure charts??
AND, why did the flow stop at 35lb. With all the concern about "overcharging" , I could not fill it further.
Thanks