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      09-08-2024, 02:17 PM   #1
Trogster
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Mystery Leak - With Pics

Ove the last couple of days, I noticed a puddle developing under the passenger side footwell.

The liquid is clear water....

We haven't seen rain in a month, and I haven't been using the AC.

I did wash the car a week ago.

I also noted that the windscreen seems to be quick to fog-up at times...usually after restarting the car following a drive (ie, car is hot).

Any idea what might be draining into that location? Perhaps the sunroof drain line is partially plugged?

Any ideas would be appreciated.
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      09-08-2024, 02:40 PM   #2
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That looks like water, not coolant or lubricant.,
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      09-08-2024, 02:43 PM   #3
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Quote:
Originally Posted by Dave07997S View Post
That looks like water, not coolant or lubricant.,
Could even be from the exhaust. My F82 used to drip water at the midpipe connection.
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      09-08-2024, 02:57 PM   #4
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Quote:
Originally Posted by Dave07997S View Post
That looks like water, not coolant or lubricant.,
Yes...it's clear water.
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      09-08-2024, 02:58 PM   #5
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Quote:
Originally Posted by ednir98 View Post
Could even be from the exhaust. My F82 used to drip water at the midpipe connection.
Interesting.... but it leaves a trail all the way down my driveway.... and a puddle on the garage floor?
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      09-08-2024, 03:36 PM   #6
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Damn. Was hoping for images of a new model.
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      09-08-2024, 03:49 PM   #7
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I thought this thread was going to be about leaked pics of an upcoming G87 model 🤦‍♂️
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      09-08-2024, 04:15 PM   #8
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Is there a possibility that the AC might be coming on when I have the climate setting to off?

Other than that, I can't explain this fresh-water accumulation.
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      09-08-2024, 07:19 PM   #9
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Quote:
Originally Posted by as7920 View Post
Damn. Was hoping for images of a new model.
Not gonna lie I clicked on this thread thinking the same
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      09-08-2024, 11:25 PM   #10
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i noticed the same dripping. i believe mine is water also but it’s a decent amount and got me a little concerned
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      09-09-2024, 10:29 AM   #11
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Quote:
Originally Posted by Ehloo View Post
i noticed the same dripping. i believe mine is water also but it’s a decent amount and got me a little concerned
I believe I may have solved the mystery..... at least partially.

The water is accumulating exactly were the AC drain is located. So any AC condensation accumulation is expected at that location.

Now the question moves to why is the AC operating when I'm not calling for it?

I learned that BMW uses a Variable-Capacity A/C Compressor suggesting it's always engaged. It does disengage under any of the following conditions:

The system will deactivate the compressor if it detects any of the following conditions:

1. The ECM detects full engine load or aggressive throttle position.

2. The evaporator temperature is less than 35° F.

3. The coolant temperature is more than 245° F.

4. The refrigerant pressure sensor (located in the high side) indicates pressure is too low or too high.

One wonders what the impact to milage may be?
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      09-09-2024, 01:26 PM   #12
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Quote:
Originally Posted by Trogster View Post
I believe I may have solved the mystery..... at least partially.

The water is accumulating exactly were the AC drain is located. So any AC condensation accumulation is expected at that location.

Now the question moves to why is the AC operating when I'm not calling for it?

I learned that BMW uses a Variable-Capacity A/C Compressor suggesting it's always engaged. It does disengage under any of the following conditions:

The system will deactivate the compressor if it detects any of the following conditions:

1. The ECM detects full engine load or aggressive throttle position.

2. The evaporator temperature is less than 35° F.

3. The coolant temperature is more than 245° F.

4. The refrigerant pressure sensor (located in the high side) indicates pressure is too low or too high.

One wonders what the impact to milage may be?
Wow if true.

So I can stop turning the A/C off to maximize power lol?
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      09-09-2024, 02:22 PM   #13
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Quote:
Originally Posted by rlove View Post
Wow if true.

So I can stop turning the A/C off to maximize power lol?
Although the AC compressor clutch may still be engaged, the compressor itself isn't doing much work. Although there may be some parasitic loss.
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      09-09-2024, 02:27 PM   #14
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Quote:
Originally Posted by Trogster View Post
Although the AC compressor clutch may still be engaged, the compressor itself isn't doing much work. Although there may be some parasitic loss.
There shouldn't be significant condensation in this case no?
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      09-09-2024, 04:17 PM   #15
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Quote:
Originally Posted by rlove View Post
There shouldn't be significant condensation in this case no?
You wouldn't think so.

I also noticed that my air-vents blow super cold air when my temperature setting is on "Low", even with the AC disabled. Suggesting that it's not being disabled at all.

BTW, all this craziness started following the last software update.
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      09-09-2024, 06:41 PM   #16
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Quote:
Originally Posted by Trogster View Post
You wouldn't think so.

I also noticed that my air-vents blow super cold air when my temperature setting is on "Low", even with the AC disabled. Suggesting that it's not being disabled at all.

BTW, all this craziness started following the last software update.
helpful work so far. forget about mileage, what are the ramifications on the life span of the compressor?
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      09-09-2024, 11:16 PM   #17
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Quote:
Originally Posted by Trogster View Post
You wouldn't think so.

I also noticed that my air-vents blow super cold air when my temperature setting is on "Low", even with the AC disabled. Suggesting that it's not being disabled at all.

BTW, all this craziness started following the last software update.
By “Low,” do you mean fan speed? If so, is your auto climate set on Dynamic or Balanced? This behavior sounds like Dynamic.

In Dynamic, the fan puts itself into the highest setting until it reaches the listed temp, then the fan speed defaults to the fan speed you have selected. In Balanced, it is always at the fan speed you have selected regardless of how long it takes to get to the desired temp.
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      09-09-2024, 11:28 PM   #18
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Quote:
Originally Posted by Digitalprty View Post
By “Low,” do you mean fan speed? If so, is your auto climate set on Dynamic or Balanced? This behavior sounds like Dynamic.

In Dynamic, the fan puts itself into the highest setting until it reaches the listed temp, then the fan speed defaults to the fan speed you have selected. In Balanced, it is always at the fan speed you have selected regardless of how long it takes to get to the desired temp.
'Low' temperature setting. I only use balanced mode.
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      09-10-2024, 07:37 AM   #19
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Quote:
Originally Posted by Trogster View Post
I believe I may have solved the mystery..... at least partially.

The water is accumulating exactly were the AC drain is located. So any AC condensation accumulation is expected at that location.

Now the question moves to why is the AC operating when I'm not calling for it?

I learned that BMW uses a Variable-Capacity A/C Compressor suggesting it's always engaged. It does disengage under any of the following conditions:

The system will deactivate the compressor if it detects any of the following conditions:

1. The ECM detects full engine load or aggressive throttle position.

2. The evaporator temperature is less than 35° F.

3. The coolant temperature is more than 245° F.

4. The refrigerant pressure sensor (located in the high side) indicates pressure is too low or too high.

One wonders what the impact to milage may be?
Hard to believe the A/C compressor would be enabled when it is specifically disabled via the climate control menu.

BTW, with my M2 I have encountered the A/C being on when it was previously disabled. (My SOP is to a few minutes before reaching my final destination for the day is to turn off the A/C and let the ventilation fan run to dry the evaporator.) Think at some point I "saved" the current settings to one of my keys and when I did so the A/C was set to on from the settings stored in the key.

I do not believe the A/C compressor is spun when disabled. I would expect there is a clutch to disengage the compressor.

The variable displacement pump feature only plays a role to control the amount of compressing of the refrigerant to thus control the amount of cooling. This is far better system than the old constant displacement compressor which is turned on and off by a clutch. This required the clutch be quite substantial. With a variable displacement compressor and the much reduced initial load the A/C clutch can be much lighter and the engagement/disengagement barely noticeable.

Using an OBD2 code reader I have monitored engine load under various conditions. With the cabin up to or down to the desired temperature -- in my case 72F -- the engine load reading barely registers the load of the A/C system. This includes the bit of load on the alternator to supply the ventilation fan with electrical power.

One can also view instantaneous fuel consumption with the current trip fuel consumption telemetry displayed and note at engine warm idle what effect on gallons per hour reading playing with the A/C controls has.

Once the cabin has reached the desired temperature the effect on fuel consumption from the A/C system load is nil. And with the A/C on and the cabin at the desired temperature the windows can be left up/closed so the car suffers less from aerodynamic drag when underway.

If the A/C is truly off -- and the water is A/C condensation water -- I wonder if the water is residual water that has accumulated in the catch tray under the evaporator -- when the A/C is enabled -- and the water is slowly leaking out due to a partial blockage of the tray drain.
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      09-10-2024, 01:57 PM   #20
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Quote:
Originally Posted by RockCrusher View Post
Hard to believe the A/C compressor would be enabled when it is specifically disabled via the climate control menu.
It's not hard for me to believe at all. I'd dicked around with enough machinery over the years to totally expect this to happen.

I have often found that machinery often does occasional utility or self-check cycles, for example to to keep grease from settling. My home AC does this even when off. So goes my house generator.

User-facing controls in the modern age often don't tell you the whole story.

And I'm not saying the G87 AC *does* do this, but I totally believe it *could be* doing this.
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      09-10-2024, 02:00 PM   #21
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One way to prove this would be to pull the fuse for the AC. (Assuming it has a dedicated fuse, I've not checked.)
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      09-10-2024, 02:21 PM   #22
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I’ve noticed this on our M240i cars and our M2 on occasion with the temp set to 60° and A/C off.

Cold air identical to A/C cold is sent into the cabin.

I simply shut down the climate control completely.

Perhaps this has something to do with inside/outside humidity or another weather factor.
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