Strange vibration - Help diagnosing needed!

beenshocked1443

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Just picked up a new to me 2005 S197. There is a strange vibration on the top end that sounds like the spin cycle on a washing machine. Hoping to get a few ideas. I replaced the spark plugs, cleaned the throttle body and cleaned the MAF. The motor only has 66k miles. Could this be CAM phasers already? Other videos of failing CAM phasers I have watched sounded more like a knock. I did have a P0506 code for the IAC duty cycle lower than expected. I also haven't had a battery connected due to a parasitic draw from the shaker radio. Not sure if it's a idle learning issue from no battery.

Thanks for taking a look!

Here is a video of the sound:

 

thump_rrr

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Remove the fan belt and check all the idler pulleys for a bad bearing.
I would even start it for a minute or so without the belt to see if the sound is still present.
Not too long since the water pump won't be spinning.
I doubt that it is phaser or timing related.
 

beenshocked1443

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Removed the belt and vibration is gone. None of the pulleys are wobbling. I replaced the lower pulley since it had a little bit of wobble, but the new one had the same slight wobble. Any tricks to testing the water pump, a/c compressor, p.s. pump?
 

JC SSP

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If you’re dead set on alignment which I don’t believe is your issue then a small leveling laser will tell you immediately. You can get them at Home Depot for a few bucks.

Let me ask… car ever been wrecked in the front? Does it do it with A/C on and off. Looks like a Saleen water pump pulley, are the rest of the pulleys stock?
 

thump_rrr

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A stethoscope or a long screwdriver placed next to each item with your ear against it works well.
 

beenshocked1443

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I hand spun all the pulleys and don't get any rough bearing feel. The alternator pulley does have some play up and down, but otherwise feels smooth.

Is that normal?

If it is, I will replace the belt, start it and do some stethoscope testing.
 

thump_rrr

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I hand spun all the pulleys and don't get any rough bearing feel. The alternator pulley does have some play up and down, but otherwise feels smooth.

Is that normal?

If it is, I will replace the belt, start it and do some stethoscope testing.
There should be no up and down movement on the alternator pulley.
The original alternator should also have a one way pulley so it cannot spin backwards.
 

Autokyrios

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For the 05-09 GT's, the steering pump pulley acts to handle the allowed amount of fore and aft play in the belt (they're also a culprit of many problems as the PS pumps are made of stupid). Anyway, point being that pulley should wiggle (in and out) a little. None of the pulleys should have a shaft wobble though. (God this is a nutty conversation...)

If you haven't replaced the belt, do so. Not worth trying to keep, they're cheap and you can rule out several issues just by doing that.
Belt tensioner won't last forever, too, but check that it moves freely with consistent oomfph on a normal breaker bar. They're cheap, too, so again, good part to replace and super easy, too.

The idler pulleys can go bad. They're a little more expensive to replace, but a great value upgrade would be the idler pulleys from Steeda (they look good, run much better, and are rebuildable). I think they're about $120.

If your water pump was bad, you'd probably know it by other problems (noise, cooling problems, etc). The pulley should have no play in it at all and should be easily turnable by hand, but shouldn't go free-spinning like a fidget toy. There's 4 bolts on the pulley. Give them a check-over to make sure they're tight (spec is 18 ft/lbs).

Testing the AC pump pulley is trickier. With no power it should freely spin as the clutch isn't engaged. Shouldn't be any play in it, though. Testing if there's an issue while engaged is easily done by running the car with the AC system all turned off and going for a drive. It should never engage the clutch if there's no demand for AC, and you can see if the vibration happens.

Another culprit that pops up on older cars is the alternator pulley. If you have any doubts about it, just replace the alternator. It'll probably be due for one anyway. Little more expensive a fix, but it's one of those "many things reliant" parts that you can't hurt yourself refreshing.

Crankshaft pulley? Eh, Check that it feels solid. There's actually a rubber damper in it but you'd have to be experiencing other issues for that to be bad (for one the whole engine would be upset all the time, not just at speed).

Vibration from the front can come from other sources, too. I'm assuming at "top end" you're experiencing this while out moving around, so you could have suspension issues (worn ball joints come to mind). Check all the mounts (and motor mounts) are good.

As for electrical...There's a decent parasitic draw for the security package when the car gets alerted to movement or anything is activated (door unluck, trunk, lights, etc.). It goes away (well, mostly) when the system goes back to sleep, but if you keep the car outside or any place where things move around the car (active garage for example) it could spin up a lot and cause a drain.

Clean your MAF (with MAF cleaner...not something else) and clean the throttle body (DO NOT USE CARB CLEANER...only use electric throttle body cleaner).

Also check your air filter. If it came with the car, consider it bad and replace it. (Another cheap solution to avoid headaches.)
 

Autokyrios

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Oh, to add, if you have a dial indicator (preferably with a magnetic base) there are specs for the pulleys, but to be honest if you can't feel anything significant with your hand you're probably fine.
 

beenshocked1443

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This is a great write up! Thanks very much! I did a little more testing on the alternator and found the overrunning pulley working as intended(only spinning one direction) but an abnormal amount of shaft play(up and down). I looked around online for an alternator and went down that rabbit hole for a good while. Remans, PAs, straight pulleys and overrunning pulleys, Chinese junk and car fires. After all that, I saw a reference to getting it rebuilt locally. I had a generator rebuilt for an old Farmall tractor I restored a few years back, so I called that guy and he said he can rebuild it unless the damage is too extensive. I'm going to pull it this weekend and drop it off next week to be rebuilt.

I'll come back and provide an update once I have it back in the car.
 

beenshocked1443

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Got the rebuilt alternator back from the shop and installed it. Vibration is gone. The guy who rebuilt it said the it was roasted inside and there was too much damage to replace bearings. Interestingly he said it was never pressed together correctly from the factory and this was the original 66k mile 2005 alternator.

Anyway it runs, drives, sounds great again and charges. Best part is that I have a quality alternator with good parts put together by someone who cares.

Thanks for all the advice and Ideas!
 

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