SWGSSSlacker

Hello,

I have a 1990 Mustang LX 5.0 Notchback that has a noise that I can't pinpoint. The noise sounds like 2 large washers rattling on a bolt but at the same time it sounds like a rotating noise.

I have removed the serpentine belt from the accessories and taken it for a short ride and the noise still occurs. So the alt., water pump, A/C comp, smog pump and P/S pump have been taken out of the equation.

The noise happens under load but not all the time.

Since I think the noise is from some sort of rotating concern I'm not sure where or what to look at. The trans, rear end, drive shaft/u-joints, throw out bearing?

Just wondering if anyone has any ideas or have experienced anything similar to my issue. I know this is like finding a needle in the haystack.

Thanks.

mechguy

Is it definitely under the hood? odd noises in my 91 GT have been the button on the emergency brake at some rpm and load combinations just makes it rattle like crazy! And the kinda loose interior panel on the underside of the back hatch at some engine frequencies.

mechguy

Is it a manual or automatic?

dawson1112

sounds like the throw out bearing to me.

SWGSSSlacker

It is a manual.

That's what I'm leaning towards to dawson1112. I'm not 100% sure but it seems to make sense.

SWGSSSlacker

And....

The noise in not inside the car for sure. When driving by yards with fences in my neighborhood it echos back to the car. It sounds like metal on metal when it happens but its a rotating noise. I do not have to have to be driving like a madman when it happens. I can be in any gear with low to medium acceleration and it happens. Once I have established a steady speed the noise disappears.

dawson1112

If it were in fact the throwout bearing , it would do it constantly even while idling. The noise would likely go away when the clutch pedal was depressed.

I have heard similar sounds if a spring or something is broken on the clutch pressure plate, or clutch plate it self. Not sure what clutch you have, but some pple who use a centerforce clutch with the centrifugal weights say that there clutch makes this noise when one or more of the weights comes loose.

It is also not unheard of to have a tire shop accidentally drop something in the tire when mounting them, it will rattle around inside the rim until enough speed is attained.

Also check your exhaust flanges , I have heard them rattle like that if one side of it is loose. It may sound rotational but its just a loose flange vibrating against the exhaust.

SWGSSSlacker

dawson1112,

Do you mean the pilot bearing?

I'm not sure what kind of clutch was installed in the car prior to me buying it.

I recently had the tires/wheels balanced and rotated but didn't notice anything rattling around in them.

I'm going to check every nut and bolt I can on the underside of the car tomorrow. This dang thing called "work" is interfering with my priorities.

88 orangepeel notch

Just to throw another wrench in here op, but do you know what pinging/ detonation sound like?

These sound/noise threads are hard to diagnose over a forum. A Youtube clip with a link posted here would help a little.

dawson1112

No the pilot bearing is set in the fly wheel, I meant throw out bearing,,,,,Buuuuttttttt since you bring up pilot bearing , that is another good guess lol . Now lets look at what the pilot bearing does...

It keeps the input shaft centered to the fly wheel, so if it goes bad and falls apart I could see it making a noise like that. Now lets throw another egg in the basket, the throw out bearing sleeve. I have known the to break and rattle around on the input shaft. I just wouldn't expect it to go away with a certain speed.