Hi All,

I am looking to buy a 1980 300TD that has an unusual noise at idle and through the RPM range. I would call it a "loping sound" (like a WA WA WA, or WU WU WU sound) but the engine is not loping - it actually idles very nice smooth. The sound is coming from the area of the air cleaner and or intake. It is not the air cleaner mounts. I did not notice the noise at cold start-up, but during and after a test drive.

The engine starts and idles fine when cold.

The passenger side motor mount is shot due to a leaky SLS pressure hose. I did not see any gross movement.

I really wish I could have taped the noise to post. Oh well.

Any ideas based on this limited description.

Thank you!

Exhaust leak, possibly?

Not a whole lot on that side to make funny noises. Unless it's coming from the top end or front of the engine- sometimes it's hard to nail down noise emanating points.

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you really need to describe the terms of the frequency and the variance of the sound in relation to RPM and load.

everything attached to the engine is vibrating; eventually, any loose vibrating item will cancel its own vibrations out (in simple terms) - use a 2x4 pushed against suspected items and use process of elimination. (unlikely)

more likely: There is a rotating item (like the fan!!) that is wobbling on its shaft trying to get free. Its vibrations also cancel eachother out in a rhythmic fashion.

least likely: One of the engine's balancing components have been installed improperly and the rhythmic noises you hear never cease but are ever changing w/ engine RPM and perhaps load.

just brainstorming

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