White Lithium
Usually general maintenance of the machine will fix and prevent squeaks. An elliptical usually squeaks due to a lack of lubricant ( it does dry out over time), dust or dirt getting into the gears and joints, or a part is broken and causing two parts to rub against each other that shouldn't be.
There are quite a number of blogs and sites dedicated to fixing equipment. The Schwinn 431 elipticals manual is actually posted on one of them: http://printer1.blogspot.com/2009/06/schwinn-431-elliptical-service-manual.html This would be a good place to start.
Please be more specific...
replace cat
In my 2004 Sienna there was a weld in the door assembly that broke and caused a loud clunking noise when I opened the door. Toyota recently issued a recall for this problem and will fix it free of charge
It could be the fuel in the tank sloshing around. Chrysler has issued a service bulliten for it and have a fix - they install a pad in the tank to prevent this, feedback on the results vary.
No way of telling w/o knowing what the problem is. have a look at www.parktool.com, www bicycletutor.com or perhaps even www.sheldonbrown.com for bike repair tips.
That sounds suspiciously like a loose suspension part.
Csytalc converter. i think bank 1 , drivers side. get a new one
As you pedal on your elliptical machine air gets sucked in and so too does dust. Taking the back of the machine and cleaning dust you can see, should solve the problem. You may need to move the pedal around while doing this.
A 2000 Commodore where the oil checks out okay at the dipstick but is dry when the oil cap of the inner housing is removed may have a faulty oil pump. This makes a clunking noise as if some cylinders have blown but may be a much simpler fix.