Metal scraping sound at idle - 2003 Jetta ALH Engine

Hello all:


My recently purchased Jetta is making a metallic scraping sound on idle.



When I purchased the vehicle I was told by the PO that the pulley was at fault for the noise. When I test drove it I did not notice anything unusual other than the underboost at high speeds (P0299).



Today after returning from work I started up the car and it was making the same noise as it did last weekend. Curious, I checked the oil to see if it was at the right level and I found metal flakes in the oil!


The car had the timing belt replaced serpentine belt replaced and the EGR pipe cleaned.



So now I am starting to think that the engine is not receiving enough oil at the cams/ pistons.


Here is a video of my engine: https://m.youtube.com/watch?v=6aqZNSLhDQE

Pull the timing belt cover and see if anything is loose.

Thanks for the reply, I’ll take a look at it later today.

Also check if the tensioner on the drive belt is bouncing around. If that’s in the timing cover though, you need to stop running the car, or it’s gonna go from a $800 job to a $2000 job to fix it real quick.

Had a MKIV in the shop last week that was making a scraping sound. All three of the bolts that hold the serp belt tensioner had stripped out their threads from the accessory bracket letting the tensioner cock sideways into the t/b cover.

Thank goodness I brought a tensioner ahead of time. The one in the car is vibrating.

Zinclay_mk2 said:

Thank goodness I brought a tensioner ahead of time. The one in the car is vibrating.

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If is vibrating/bouncing , then you may have bad Alternator pulley and that could be where noise coming .
Take drive belt out and see do you still have noise.

When you checked the oil did you see metal flakes on the dipstick?
That would worry me more than the serpentine belt issue.

flee said:

When you checked the oil did you see metal flakes on the dipstick?
That would worry me more than the serpentine belt issue.

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It worries me a lot but from what I was told and read online it is from normal wear and tear. Given the condition of the car I would not be surprised if PO overlooked this.

From what I seen it was not huge chunks but more like glitter. If necessary I will drop the oil pan but I need to buy the ball socket to detach the pan from the transmission.

jetta said:

If is vibrating/bouncing , then you may have bad Alternator pulley and that could be where noise coming .
Take drive belt out and see do you still have noise.

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I brought a alternator pulley as well and the metalnerd alternator removal tool at the same time as the serpentine belt tensioner.

From what I’ve read it’s best to swap both out at the same time.

Zinclay_mk2 said:

It worries me a lot but from what I was told and read online it is from normal wear and tear. Given the condition of the car I would not be surprised if PO overlooked this.
From what I seen it was not huge chunks but more like glitter. If necessary I will drop the oil pan but I need to buy the ball socket to detach the pan from the transmission.

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First drain the oil into a pan and see what you get. Hopefully nothing so big as to
lead to removing the pan. I've never seen any 'glitter' on the dipstick, though.

flee said:

First drain the oil into a pan and see what you get. Hopefully nothing so big as to
lead to removing the pan. I've never seen any 'glitter' on the dipstick, though.

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It appeared in the oil on the dipstick when I was checking the oil level.

Welp, today I got down and dirty with the car (lol) and removed the belt and started the car. The noise disappeared and upon further inspection it turned out that the alternator was the source of the metal scraping noise. Not only was it causing the noise but the shaft was wobbled so I am in the process of buying a new alternator. While I was thinkering I replaced the worn serpentine belt tensioner and idler pulley.

Now that the noise issue has been solved my car needs its injection timing tuned. The PO mentioned
that the timing was retarded and need adjustment. I will buy a rosstech hex usb and do the adjustment myself. I believe the engine timing is causing it to run rich, idle rough and expel white smoke upon start.

I also discovered that I have a snapped spring on the driver side and that the ac condenser & radiator are trashed so that’s more money to throw at the car lol but is worth every penny.

Thank you guys for the input and direction

Glad it was something simple,and thanx for the update,thread closure is good.

It's not encouraging that the engine is said to have its timing retarded after a TB.
I would want to verify that the cam and pump are timed correctly with the crank.