Water out of the exhaust - A4 3.0 Quattro

Hi,

The other day my wife drove my car and I drove hers, she decided to show me how fast mine is by leaving me behind while pulling onto the motorway. When she changed gear I was surprised at how much water came out of both exhaust pipes.

Any ideas why this happens? I assume it was water, would it indicate a problem?

I hadn't just been through the car wash or anything and the road's have been dry for several days, the car has also done about 5-6 miles before this happened so the engine was warm.

Thanks in advance

Daz

Reply to
Daz N
Loading thread data ...

One of the main gasoline combustion products is water which due to the combustion temperature will be in the vapor phase as the combustion products exit the engine through the exhaust valves. When you first start a car, the exhaust system components will be cold and the water vapor will condense out.in them - mostly towards the rear of the car. If you drive sedately while the car warms up, this liquid water will gradually heat up with the exhaust components and be revaporized and blend with the exhaust. What likely happened is there was insufficient time for the water to be re-vaporized before your wife put her foot down. The added rush of new exhaust blew the still liquid water out the tailpipes and that's what you likely saw.

I assume it was water, would it indicate a

In the absence of smoke of some sort accompanying the water, it is unlikely problematic. A similar thing happens in cold weather when the warm moisture laden exhaust contacts the cold air outside the exhaust and the water condenses to "steam".

Reply to
Ian S

The water is a by-product of the combustion process

Does your car do lots of short journeys? It takes the exhaust system quite a bit longer to heat up compared to the engine. If your journeys are quite short then the water won't get a chance to evaporate. In time this will destroy the exhaust system.

I was following a Toyota something or other a few weeks ago and when they accelerated away from some lights it was like someone had turned on a hose! I couldn't believe how much water came out.

Reply to
Dave

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.