Why does my Saab sound like a motor boat?

Recently my Saab 9-5 Linear sounds like a very loud motor boat when I start it up. It gets quieter as it warms up. Once it is fully warmed up, it is quiet as usual unless accelerating up hill. It is silent on the highway. But, first thing in the morning, I can wake the neighborhood upon lift off, I mean on start-up.

Background info - 2002 model year, 61,000 miles, full 60k mile service done about 2k ago in January, at that service the oil pressure sensor was replaced as was the belt idle pulley (or something like that), this car has been trouble free its entire life.

I would say that you probably have a bad gasket on your exhaust manifold. Park the car at the mechanic’s shop at night so that he can hear it in the morning when the engine is cold.

My trusty Saab mechanic is 4 hours away (which is why I came here to ask:). Is that something any mechanic can work on or should I finally find a Saab guy in my town? And, is that something expensive to fix, not that anything on a Saab is cheap?

Any more ideas out there?

I agree with VDCdriver. What you describe sounds like an exhaust leak, most likely a manifold gasket or the flex pipe. When the metal is cold the exhaust leaks, and since the leak is forward of the muffler you hear it clearly. As the exhaust heats up the metal expands and seals the leak. When you accelerate the engine shifts slightly on its mounts, opens the crack, and you hear the noise.

Whether you choose to drive 4 hours to have this repaired or have it done locally is up to you. Without knowing exactly where the leak is it’s impossible to estimate repair cost.

I wouldn’t wait too long to get this fixed. The leak will get worse over time, and you don’t want to be breathing exhaust fumes.