engine and drivetrain Hissing

[MikeR]

Standing on intake side of the engine, I'm hearing a hissing sound. Noticeably quiter from the other side. My first thought was the brushes in the alternator, but I'm not sure. Given mysurgibg problem, I suspect a vacuum leak. Thoughts?

Name that noise!

[Marty]

It sounds like a vacuum leak, I doubt the brushes would be loud enough to be heard over the engine. Spray the base of the carb, hoses and all the manifold gaskets with wd40 and see if the idle/noise changes

[Guest Anonymous]

Agree with Mt. Ranier Marty.

If you really think it could be an alternator, why not eliminate it from the equation by either disconnecting the rear plug - thereby removing the load from the device or loosening or even removing the fan belt for a short run.

I am not familiar with your problem, but it seems it should be relatively easy to pinpoint by taking a length of vacuum or fuel hose and running it from your ear to the various areas of the engine you suspect as noise making.

[dapbmw]

sounds like vacuum leak on your intake mating surfaces, either tighten uip the manifold/s or put new gaskets or double up the gaskets, this solves hissing a lot as some mating surfaces over time develop a bit of warping so they are not as flat anymore.

[robspeed]

It sounds like a vacuum leak, I doubt the brushes would be loud enough to be heard over the engine. Spray the base of the carb, hoses and all the manifold gaskets with wd40 and see if the idle/noise changes

dont use wd-40, unless you want your engine even filthier than it was before... i use carb cleaner or brake cleaner, that way the motor ends up slightly cleaner afterwards ...