Water on cold start up under car

[Seanay]

Hi all, just bought a 16 GT and noticed that every day a small puddle of water forms under the car wherever it sat for a minute before driving off .Is this normal for mustangs? It's consistent and happens whether it's 40 or 70 outside.

The water pools on the ground right around where the mid pipes or resonator would end, more slightly to the passenger side than driver side. I live in Orange county, califCalif so it's very mild weather to warm.

I have not seen this before with other brands I have owned and have no idea what is causing it and where the water is coming from. If anyone has any idea please let me know and thanks

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[BmacIL]

Hi all, just bought a 16 GT and noticed that every day a small puddle of water forms under the car wherever it sat for a minute before driving off .Is this normal for mustangs? It's consistent and happens whether it's 40 or 70 outside.

The water pools on the ground right around where the mid pipes or resonator would end, more slightly to the passenger side than driver side. I live in Orange county, califCalif so it's very mild weather to warm.

I have not seen this before with other brands I have owned and have no idea what is causing it and where the water is coming from. If anyone has any idea please let me know and thanks

There is a significant amount of water in exhaust gas. It is probably dripping out of the resonator (which may have a drain hole, I don't recall).

 

[Seanay]

If that's what it is, should I be concerned. Is the water condensation or something I need to refill?

 

[GMB Racing]

you will need to refill the blinker fluid if it continues for a long time.

 

[Seanay]

So this is water that's leaking from somewhere inside the car you think?

 

[DickR]

So this is water that's leaking from somewhere inside the car you think?

It is normally condensation from when water vapor which is a product of combustion condenses in the cold exhaust system. What doesn't condense is frequently visible as "smoke" coming out the tailpipes until the engine and exhaust system reach operating temperature.

Alternately or in addition if you have been using the A/C it can be condensate from the A/C evaporator which has its drain roughly under the firewall on the right side of the car.

Both are absolutely normal.

 

[Anthony 05 GT]

Don't worry about this. When you park the hot car the exhaust collects water from the atmosphere and it finds it's way in there for whatever reason. When you start the engine it will either leak at exhaust joints or burn off. Haven't you seen cars blowing steam out the exhaust on a cold morning before? Same thing

 

[GT Pony]

Don't worry about this. When you park the hot car the exhaust collects water from the atmosphere and it finds it's way in there for whatever reason. When you start the engine it will either leak at exhaust joints or burn off. Haven't you seen cars blowing steam out the exhaust on a cold morning before? Same thing

It's not "collecting water from the atmosphere" ... like others have said, it's water vapor moisture in the exhaust gasses (from the normal combustion process inside the cylinders) that is condensing to liquid water when it cools off inside the exhaust system. I get two small water puddles out of the drain holes in the bottom of the mufflers on my GT. Those drain holes are there so the mufflers don't collect and hold the water.

 

[ChromaticGrey]

It's not "collecting water from the atmosphere" ... like others have said, it's water vapor moisture in the exhaust gasses (from the normal combustion process inside the cylinders) that is condensing to liquid water when it cools off inside the exhaust system. I get two small water puddles out of the drain holes in the bottom of the mufflers on my GT. Those drain holes are there so the mufflers don't collect and hold the water.

To be fair that water does come from the atmosphere.

 

[GT Pony]

To be fair that water does come from the atmosphere.

Yes obviously, but it's air that's going into the engine through the intake system while the engine is running and used for combustion. It's not going up inside the exhaust system when the car is shut off - that's what I was clarifying.

The post I replied to said: "When you park the hot car the exhaust collects water from the atmosphere and it finds it's way in there for whatever reason."

 

[FreedomPenguin]

To be fair that water does come from the atmosphere.

killed it, made me laugh out loud in real life.

 

[ChromaticGrey]

Yes obviously, but it's air that's going into the engine through the intake system while the engine is running and used for combustion. It's not going up inside the exhaust system when the car is shut off - that's what I was clarifying.

The post I replied to said: "When you park the hot car the exhaust collects water from the atmosphere and it finds it's way in there for whatever reason."

Good point.

Though I do think the water you see at start up is a mixture of what you see from what comes through the engine like you said. But also air that found its way in while the car parked and cooled from last time driving. As air was sitting inside the exhaust and it was cooler on the outside vs. Inside, and the moisture then condenses inside and trickles out on startup. This is an observation, not suggesting I'm right, just mentioning it. Cheers.

 

[ChromaticGrey]

Hi all, just bought a 16 GT and noticed that every day a small puddle of water forms under the car wherever it sat for a minute before driving off .Is this normal for mustangs? It's consistent and happens whether it's 40 or 70 outside.

The water pools on the ground right around where the mid pipes or resonator would end, more slightly to the passenger side than driver side. I live in Orange county, califCalif so it's very mild weather to warm.

I have not seen this before with other brands I have owned and have no idea what is causing it and where the water is coming from. If anyone has any idea please let me know and thanks

I would not worry about it.

 

[GT Pony]

Good point.

Though I do think the water you see at start up is a mixture of what you see from what comes through the engine like you said. But also air that found its way in while the car parked and cooled from last time driving. As air was sitting inside the exhaust and it was cooler on the outside vs. Inside, and the moisture then condenses inside and trickles out on startup. This is an observation, not suggesting I'm right, just mentioning it. Cheers.

Only way that could ever happen is if the air was very humid, then a cold snap happened and suddenly cooled everything down. In a freak case like that, there would also be moisture condensing on every surface of the car, even inside the car's interior. When the exhaust system is hot, and the engine is shut down, no water forms inside the exhaust system as it cools down, even if some fresh air works its way inside the system. That would be like saying water condenses from the fresh air getting inside your hot oven with the door cracked open as it cools down - that's never going to happen.

If you watch the end of the exhaust system right after a cold start up, it takes a minute or so for moisture to start showing up. If water was laying inside the exhaust system before initial start up you'd see it coming out the exhaust in few seconds.

 

[DickR]

Good non-technical explanation here:

https://shop.advanceautoparts.com/r/advice/cars-101/what-your-car-exhaust-system-is-telling-you

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