Scarey Engine Noise

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Oct 30, 2001 | 10:39 AM

puppy

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Scarey Engine Noise

I have a '97 Expedition, 5.4, 4wd automatic w/ 70k miles. It has developed a loud internal rattle at idle and occasionaly at driving speeds that sounds like a loose bolt whirling around the bell housing. It occurs randomly and does not have a constant frequency like rod, main or piston noise. Since it sounded like it was in the back of the engine, I suspected the starter gear was not fully retracting and occasionally would strke the flywheel ring gear. After removal I see no evidence of that happening. Removing the inspection plug and plate from the bell housing, I see no metal shavings or loose pieces although my view is limited. The noise changes in frequency with engine speed but not in a constant manner. Another nightmare might be the oil pan wingage tray is loose and moving around with oil level. Seems a little remote. Short of removing the transmission to inspect the flywheel and torque converter, does anyone have any suggestions. I tried to pinpoint the location but it is so loud it could be emminating from anywhere other than the top side.

Oct 30, 2001 | 05:34 PM

adelyser

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Scarey Engine Noise

The only time I have heard a noise like that is when the catalytic converter is shot. I have had that happen on two different vehicles, and it sounds like hell. Other than that, I have no idea. Good luck!
Aaron D

Oct 31, 2001 | 06:32 AM

puppy

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Scarey Engine Noise

Thanks Aaron,

Forgot to mention that I too thought the driver's side catalytic converter was the source and went through the grief of breaking and repairing manifold bolts to get it off only to find nothing loose inside. Changed the starter last night. Still is the most likely candidate. I'll keep your experience in mind. Thanks again for the help.