Turbo clicking when running

[kjhansen]

Turbo is a PTE PT5858.  Makes an obvious clicking sound when the engine is running--even when the car is idling.  Could this be a valve train sound being channeled through the exhaust?  I put the stethoscope on the valve covers and don't hear the noise through them, so I don't think that's where the noise originates.  A clicking sound from the turbo sounds expensive.  Can I rebuild this turbo? 

[Steve Wood]

I think I would remove the inlet pipe/hose off the compressors side and then check the turbine shaft for both in/out movement and side to side movement.  Also, I would feel how smoothly it turns using your fingers on nut.

It should have basically no perceptible in and out movement and only slight side to side-not enuf to touch the housing around the compressor blades.

[ULYCYC]

Also take off the serpentine drive belt and run engine without it. They are known to make ticking sound when worn, too tight or loose.

[kjhansen]

The ticking continues.  Only I don't think it's from the turbo, which is almost brand new.  I took off the air inlet side from the air cleaner (had to clean and re-oil the K&N anyway) and spun the turbo.  It spun freely and made no noises.  It also had NO play side-to-side or fore-and-aft.  So I looked down the down-pipe.  It appears to be actually or almost (like a millimeter) away from the upper suspension bits.  It's wrapped with exhaust insulation stuff, but if it IS tapping on the suspension piece it has probably worn through and is cooking the upper A-arm bushing.  Not good.  More investigation is required with a stronger light. 

[Steve Wood]

did you take off the belt as Ed suggested?

Sounds like it is motor mount time on that down pipe

Be sure it is not an exhaust leak as well

[kjhansen]

The serpentine belt is new, so it's not that.  The turbo is also just fine.  I decided to clean and re-oil the K&N (it was looking kind of dry), so took the opportunity to remove the inlet pipe from the turbo.  It spins freely and makes no noise.  Also there is no side-to-side or fore-and-aft play.  That's to be expected in a practically new turbo, so I really wasn't surprised.  The down pipe is definitely in contact with or extremely close to the rear of the upper A-arm. But it can't be because of a worn motor mount since those are also new--the old ones are in a box that the previous owner sent me.
So maybe I'll put an engine tie-down on the driver's side.  I used to have one in my old Regal.  It wasn't a strap though.  It was a turnbuckle bolted to the alternator on the top and with a hook into the frame below.  I think if the tie-down just pulled the engine down 1/8th of an inch on the driver's side it would prevent the rattle.  That would stress the driver's side motor mount though.  Plus, on my old car, the turnbuckle constantly needed tightening.  So maybe I should just remove the downpipe and make a slight indentation at the point of contact and reinstall it. 
What do you think?

[Steve Wood]

It is not the belt.  We take the belt off to see if the noise goes away because the idler pulley is well known to make a clicking noise as the bearings in the pulley wear out.

[kjhansen]

Ahha!  Will try that.