Why Is Exhaust Only Coming Out of One Tailpipe?

There are times when exhaust only comes out of one tailpipe.

Many cars either come standard with dual exhaust or can have it added on, but exhaust will not always come out of both tailpipes. There are times when that is normal, but it can also mean there is a problem.

Function

Dual tailpipes are used to expel exhaust after it has gone through the muffler and the catalytic converter. A butterfly valve at the base of the dual exhaust pipes directs the exhaust through the two pipes.

Warming up

In some cars, the exhaust is directed only through one exhaust pipe for the first 30 seconds to a minute. It will look as if the exhaust is only coming out of one pipe. Once the car has warmed up, the butterfly valve opens and directs the exhaust through both pipes.

Blockage

The other reason why exhaust would only come out of one pipe would be if the other pipe was blocked. Occasionally, dirt, snow and other material can become impacted into the pipe or the pipe can be bent from an accident and prevent the flow of exhaust through the pipe.

References

• Auto Education.com: Exhaust System
• aa1car.com: Exhaust Troubleshooting