Water leak?

[Sfive50]

I've been lurking these forums for quite some time and I rarely ever post. In fact this may be my first...As of lately when my car is idling for any period of time water is building up somewhere. I can hear the water flowing when I press the gas pedal. It happens in park or drive, but more-so in park...It doesn't happen during daily commute unless I place the vehicle in park and allow it to idle for 20-30 seconds.

For example I can sit at any given red light, in drive, for 20 seconds easily(if not longer) and when I begin to accelerate I don't hear any rushing water. However, if I use my key fob to start my car, allow it to idle until warm, give it a little throttle, in park, I hear what sounds like rushing water. This hasn't always happened. I'm just shy of 23k miles...

Unfortunately I don't have anywhere to garage her for the time being. I just assumed that the water is being trapped in the door or around the firewall near the cabin filter due to recent rains. If that were the case you would think the "water" would slosh around between directional changes or even leak into the cabin itself. I don't hear this noise while turning, or reversing. It sounds as if it's coming from inside the dashboard. Also, I can't hear this noise from outside of the vehicle. The car is completely bone stock, even the sound tube is still intact. Oh, and this noise occurs regardless of the A/C and heat being off.

I was leaning towards the evaporator being faulty as I have read on a separate forum board about that happening to someone else who owned a 2015 Mustang, but none of those threads remotely describe what I'm experiencing. I live in NW Florida and it's been kind of chilly lately, so I haven't had to use the A/C at all. By kind of chilly, I do mean lower than 70 degrees...lol...

Anyway, this noise has been occurring almost two weeks now. Considering I'm still under warranty I figure I'll be making a service appointment with my local dealership, but before I take that route I figured I would post...

TL;DR - I hear what sounds like rushing "water" when I press the throttle after idling in park, or drive.

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[AMFTexas19]

I know this is an extremely old post. But wondering if you happened to learn what was causing this?
I get the same water sloshing noise with my 2020 GT
Mainly hear it at start up, dont hear it while turning or anything. But its quite loud and coming from directly behind the dash. I dont have any water leaking into the car at all.
Hoping you are still on this forum and found an answer.
Much appreciated in advance!

 

[GT Pony]

Yes ... old thread resurrected. Sounds like it could be air in the cooling system if it does it after idling and the engine is revved up some as the OP described. Had a Toyota truck that made a sound like (sounded like it was coming from right behind the dash where the heater core was) after I changed the coolant and the cooling system had some trapped air in the system.

 

[Skye]

https://www.mustang6g.com/forums/threads/ac-evap-drain-tube.126141/

If you believe the area where the evap core is housed is holding water, @pyrophilus provides description and photos in the thread above.

https://www.mustang6g.com/forums/th...battery-box-if-your-car-stays-outside.201220/

Another place you might want to check, the battery holding bin. @DonnieO discovered that area.

https://www.mustang6g.com/forums/threads/cowl-drain-valve.132078/

The cowl area. Maybe some water sloshing there.

https://www.mustang6g.com/forums/threads/water-leaks-master-thread.123828/

If after all that you still hear sloshing, check out this master thread, authored by @canvert

For those of us with home heating and cooling systems, check your drain pipes. I make a habit of, every time I change the filter (60 day intervals), I pour white vinegar down the drip line tubing until I hear or see it exiting. The acid of the vinegar prevents mold from forming and the line from stopping up (leading to wet carpets, basement or garage).

 

[AMFTexas19]

Awesome I will check into these. Thank you very much!!

 

[ApplesAndOranges]

Definitely sounds like air in the cooling system, or low coolant. I've drained the coolant serveral times from a couple Mustangs over the years. The heater core radiator is located directly behind the dash and it happens to be the high point in the coolant system. When you initially step on the accelerator, the water pump spools up and pushes fluid through the core. It sounds like trickling fluid.

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