X5 E53 Air Conditioning - all systems go but no cold air

[OnewireAT1]

Originally Posted by upallnight

See the comment in this Youtube video

https://www.youtube.com/watch?v=-Lvpdp7NTdY

LMAO

LMAO x2

[OnewireAT1]

Originally Posted by upallnight

Never know the the mechanic skill of some of the noobs that post here. I seen noob connect the hose and forget to turn the knob to open the valve. Pressure on the gauge could be left over from a previous use if the valve for the gauge were closed before disconnect.

Yes I am a noob to AC but NOT a noob to trying logic out troubleshooting and realizing that I need to provide the best input to you wonderful people in order to get good help.

[upallnight]

Originally Posted by OnewireAT1

I was wondering with regards to the Heater Control Valve... I gleened that the heater core is normally open without power. This means that hot water is normally flowing through the heater core and could create a always heat scenario.

However, after thinking about this more .. If the car has not been run today .. and it is 75 degrees here, there would NOT initially be hot coolant flowing through the core.. and if this were the only issue then I should have initial AC of some sort and then it would get hot with the car..

Voting : Agreed ? / Disagree ? / Makes no sense?

I was also reading on how some HVAC systems actually have what is called a "Blended vent system" which is control flaps that separate the heating (heater core) from the cooling (Evaporator). Seems like X5 E53's have a lot of flap valves but I am not sure if it is only for the airflow itself OR if it is truly a blended - in my example I mean ..

A flap which must move in order to allow ether of the following two conditions:
1. heater core HEATED air to enter the cabin
OR
2. Evaporator CHILLED air to enter the cabin

As I am writting this.. I am remembering 2 facts, (1) my gauges are showing LOW Freon @ 37PSI (2) the gauges read same low 37PSI on both the LOW side and the HIGH side... the High side should be reading around 145PSI @ my outside ambient temperature of 70F.

This would suggest a bad compressor; however, the low pressure fill port shows full @ 37 to 50PSI .. so for some reason perhaps something is blocking the Freon from filling ?

IDK

Please feel free to chime in with any additional thoughts or consideration here.

Sounds like you are using one of those hope it get my AC cold in the bottle to add refrigerant to the system. Is the Engine running and the compressor running when you squeeze that trigger? If not that is part of the problem you don't know how to add refrigerant to the system. Engine needs to be running and compressor needs to be running to add refrigerant on the low side into the system. The manifold gauge that you have hookup to the system shows 35 to 37 on both the lowside and high side. That will indicate a low charge. A Static charge should be at least 70. That is with the compressor not running and low side and high side has equalized.

Since you are a noob to the X5, on the center vent there is a thumbwheel that has red dots and blue dots on the wheel. What color dot is showing on the thumbwheel? Is it Red or is it Blue? If it is Blue you have other problem as to why you don't have AC. If it is red that could be your problem. Turn the thumbwheel until you have the maximum number of blue dots showing.

[OnewireAT1]

Ya.. no. I initially tried adding Freon to the low side (no X5) experience needed for that.. however, I took it to a shop to have it vacuumed and refilled..

Yes I am aware that the compressor needs to be running to add from the low side..

I also understand that at off .. (the system may simply be equalized *high and low as the same)

I’m pretty sure that only the compressor needs to be running for the AC and not the engine [gotcha] [levity is always welcome]

I would not post here for the gurus if it was simple


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[OnewireAT1]

I suppose that the real question at this point is why? Why if they filled would my reading be so low.. ?? Humm.. perhaps I need to go back and have them recharge. ... since the system has managed to keep the 37’ish PSI for days I was assuming no leak was present. And I’m supposing that with a high side reporting only 37PSI perhaps the compressor cannot function that low..
I am then puzzled why the compressor clutch would engage if there were truly inadequate pressure in the system.


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[upallnight]

A shop uses a machine to fill an ac system. They will evacuate the system of all refrigerant, and continue to evacuate to boil of any moisture in the system. They will use the same machine to install a predetermined amount of refrigerant by weight back into the system. Hopefully your shop have this type of equipment. Adding refrigerant through the low side port is "Old School" and backyard DIYer.

[andrewwynn]

I haven't measured my system when not running but I'm pretty sure the equalized pressure is a lot higher than 37. Did you have cold air after the refill and have you tried at not idle?

I've seen when the car was idle not making cold but when driving it will. I attribute to a problem with the variable compressor.

If there is no difference in high and low side means compressor is doing nothing. If the clutch engages means there is enough pressure for the low pressure interlock to allow it to kick on.

Were this my car id be pulling off the clutch mechanism for a rebuild but don't think there is enough room to work under the car might have to take out the whole compressor.

If the problem was not compressor related you will get substantial pressure difference.

The cans have about 50 psi full and maybe 30 psi empty. You can't get freon out of the can unless the compressor pulls a vacuum on the low side and drops the pressure.

[oldskewel]

Just some clarifying comments ...

disclaimer - I've never had to do anything on my X5's AC, so this is just from general understanding of AC systems and maintaining my other cars. But I think the R12 or R134a and physics still apply.

On the manifold gauge set, first thing to do before hooking it up is to close both of the valves at the manifold (the brass thing that the gauges and lines connect to). Turn the red and blue knobs right next to the gauges clockwise to close them. With those valves closed, the gauges will still read the pressure in the line, but nothing else will flow - e.g., from the yellow fill line to either side, or from blue to red.

If those valves are both open, the H and L pressures will be equalized within the manifold, which is definitely not what you want. If either one is open, it will connect that line to the output (center, yellow) line, which appears to be plugged in the photo.

Then hook up the lines at the ports. From your description, it sounds like that is done exactly right. You will also want to bleed air from the lines, but that is a secondary factor at this point.

With then engine off and the AC system stabilized (i.e., given enough time after shutdown to allow things to flow and equalize), you should be reading equal pressures in H and L. Looks good.

The pressure you read in this state is mostly an indication that you have (1) gauges hooked up right, (2) freon in the system, and (3) ambient temperature (not the thermometer on the wall in your garage, but the effective temp of the engine bay, specifically the entire AC system). If you are very low on freon, there will be no liquid in the system, and the pressure will be below whatever you would get when you do have liquid in the system. Details follow.

When you do have liquid in the system, it is a saturated vapor, and whether it is overfilled, underfilled, or perfect, the pressure reading will vary the same as ambient temperature goes up and down.

From the numbers you're reporting, if the gauges are hooked up right and your numbers are accurate, it sounds like you are low on freon and do not have a saturated vapor. It is all vapor. No liquid in there. This would prevent the compressor from running.

If you look at the gauges, the red numbers (temperature units) on inner rings are refrigerant dependant - specified as R134a for your gauges, and they assume that the refrigerant is a saturated vapor. In a saturated vapor, changes in volume at constant temperature cause it to condense/evaporate fast enough that the pressure remains constant. So there is a direct relationship between temperature and pressure IF it is a saturated vapor (at the very least, this means that both liquid and gas are present). So these markings on the gauges are doing this pressure-to-temperature lookup for you - valid for a saturated vapor.

Since your pressure numbers are well below what you'd expect at your temp, it sounds like you have only gas in there. Freon needed.

Then, you reported that after running the AC, pressures in both sides increased equally from 31 to 37.
- equal could be explained by the manifold valves mistakenly opened. hopefully not.
- equal and low means the compressor is not compressing. probably.
- the raise in temperature is probably due simply to the ambient temperature rising. Even with your AC belt removed (as an extreme example), running the engine will warm everything up in the engine bay, including the AC lines. This will cause the pressure readings to increase. As the temp rises, those gauge readings will keep going up.

Maybe all that was done correctly already, and was clear to everyone. But if not, hopefully it helps.

[OnewireAT1]

Originally Posted by upallnight

A shop uses a machine to fill an ac system. They will evacuate the system of all refrigerant, and continue to evacuate to boil of any moisture in the system. They will use the same machine to install a predetermined amount of refrigerant by weight back into the system. Hopefully your shop have this type of equipment. Adding refrigerant through the low side port is "Old School" and backyard DIYer.

Thanks upallnight! Evacuation and filling is what they “claimed to have done initially” I’m questioning that from my test results.


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[OnewireAT1]

Originally Posted by andrewwynn

I haven't measured my system when not running but I'm pretty sure the equalized pressure is a lot higher than 37. Did you have cold air after the refill and have you tried at not idle?

I've seen when the car was idle not making cold but when driving it will. I attribute to a problem with the variable compressor.

If there is no difference in high and low side means compressor is doing nothing. If the clutch engages means there is enough pressure for the low pressure interlock to allow it to kick on.

Were this my car id be pulling off the clutch mechanism for a rebuild but don't think there is enough room to work under the car might have to take out the whole compressor.

If the problem was not compressor related you will get substantial pressure difference.

The cans have about 50 psi full and maybe 30 psi empty. You can't get freon out of the can unless the compressor pulls a vacuum on the low side and drops the pressure.

Thanks andrewwynn!

I think the compressor is the culprit at this point. But the shop should have seen this!?


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