What sound does a failing chain tensioner make?
 

Earlier I posted about a sound that I thought could be an alternator bearing. But the alternator does not seem to be the source of the noise.

What type of noise does the chain tensioner make if it is failing? Should I park it immediately if that's what it is? I have a stethoscope, but I don't know what a bad sound might sound like, because what I hear through it isn't the same as what I hear otherwise.

If the noise your'e hearing goes away at higher RPMs it's likely the tensioner.
DON'T let it idle!

You can remove the fan belt and eliminate the fan / alt. noise to see where it is coming from.

Chain over a steel garbage top is how it is frequently described. A stethoscope type device helps compare sound from each side of the chain boxes.

Chris

Don't start it until you have taken the chain covers off to check the tensioners.

I drove my 2.7 300 miles with a collapsed tensioner. in the car it sounded like I had a very bad exhaust leak or rattle. I actually thought it was leaking past the cylinder and head.
the motor was old and tired and I had to drive it as I was out of town. 3 days of mountain road driving did it in.
I don't recommend driving it if you don't have to.
I also started it back up after getting home to investigate it some more.

its really loud at idle, more or less goes away as RPM's go up

Thanks for the advice so far, guys.

But, against some of that advice I just went out and started it, and let it idle at ~1,000 rpm.

Using a stethoscope, the chain cover noise on the right side was way louder than on the left. This isn't good, probably.

That said, the noise does not sound like a chain being dragged over a metal garbage can. It's pretty useless to try to describe the noise in written form here, but it was a louder hissing sound.

I am going to try to have a well experienced Porsche restorer listen to it. He lives nearby.