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Discussion Starter · #1 · (Edited)
Hi guys,
I cannot seem to figure out what this strange rattling sound is on my 03 Passat with the 1.8t. (I have attached a link with a recording of the sound)

Symptoms:

It's really bad on cold starts and then almost goes away when it's warm. It won't come back on start-up, unless it's cooled right back down to cold again. It does make that noise even after being warmed up just a little bit sometimes when accelerating.

What I tried already:
I tried cleaning the pick up screen (it was already clean) checked the Combi valve (it still makes that sound with the Combi completely removed), changed the oil weight to 0w40, ran a degunker in the oil, still the rattling sound has persisted.

I was hoping one of you had maybe had the same issue and knew what it was. Any input from someone that's had this issue would be much appreciated please!!

Here is the recording:

You can hear what it sounds like on acceleration at the end of the recording
 

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Please don't rev it like that any more :cry:.

Sure sounds like a bad cam chain tensioner at the back of the head.

Also sounds like you may have a leak in the corrugated tubing from the secondary air injection pump behind the passenger side bumper under the airbox.

Any check engine light? If so, post the code(s).
 
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Before you actually pull the tensioner, take a look at the underside of the valve cover. That much noise should be wearing a line on it from all the slop in the chain flopping around, if that is the case. Could be obvious from looking at the tensioner as well, like a missing guide shoe.

After you check that out, order a new tensioner if it looks bad. I would not drive it or run it at all until fixed. If it jumps a tooth on the chain, you’re looking at a lot more than just a tensioner; like new valves or reconditioned head.
 
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Discussion Starter · #5 ·
Ok I won't be driving it, thanks for the heads up.
I pulled the valve cover and there is no scoring/scratches on the underside, there was a fair amount of brown oily gunk caked on though.

The tensioner isn't missing parts of the shoes, they are both complete, and the chain doesnt seem loose on it.
I did notice that the upper shoe on the tensioner doesn't compress down as much as it does on the other tensioner I bought from the salvage yard though.
I'm thinking the tensioner could be bad, or stuck maybe. Is that possible do you think?
 

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You bought a used tensioner from the salvage yard?
'myeah I don't know about that. Everybody has their own way of justifying the money they spend but this is a mission critical part.
Kudos if it works, but any component that fails related to the timing can be catastrophic and the end result will cost way more than coughing up a bit more cash for a sound quality part up front.

Just my .02 cents.
 

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Discussion Starter · #7 ·
I get that, thanks for your input. I'm a broke international student that bought the car for 1k so I can't really justify spending ~150 on a new part when I can get a functional one for a lot less. I need it to get from A to B, not too concerned about keeping it long term or doing road trips... Thanks though, I definitely understand your perspective.
 
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