saturn sl/93 start up noise

When I start up the engine, the car vibtates with a loud sound. If I drive
it with out letting it warm up for at least 15 minutes it takes about 30
minutes for the noise fade. But, if I let it warm up, there is no noise
when I begin to drive. Thought it was a bad stering pump or the air cond.
so I replaced the belt to by pass them, no change.Took out the thermostat,
changed the oil, no change. The car runs with out loss of power and drives
normal when the sound goes away. What could it be ? Am I driving a ticking
time bomb?
Thanks to anyone who can help.

 

Not sure with the vibration part, but did you check the belt tensioner
and idler/bearings?

Remove the belt entirely and start engine to see if noise goes away.
You can run the cold engine a minute or two with no harm. Not sure
where you were going with the thermostat removed.

Removing the belt will eliminate all the accessories being an issue.

James

 

James
thanks for replying ,I'll try removing the belt and will lt. you know. I
thought that possibly it might be the water pimp or something temperature
related because the noise goes away when the car has warmed up. I'm
puzzled?
Your help is appreciated . ken
p.s. I live in a warm climate that doesn't require a thermostat.

 

You should use a thermostat in any climate. I doubt it is 180° where
you live.

James