exhaust leak after timing belt change?

milktree

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2015 Golf Sportwagen, 2004 Jetta Wagon (sold!)
I just had my timing belt replaced[1] and since then I can smell exhaust in the cabin at start up. It goes away reasonably quickly once I start driving. It doesn't seem to happen when the engine is hot, but there might be confounding factors.

So:

Is there any part of the timing belt change process that could cause this? e.g.: some part of the exhaust system that needs to be removed, and maybe wasn't put back on quite tight enough.

I'd have guessed "no", except that the "exhaust on startup" wasn't there *AT ALL* before the timing belt work, and showed up on the first start when I picked up the car from the shop.[2]



[1] and water pump and serpentine belt and tensioners and pulleys, of course

[2] the shop was closed when I picked up the car, so I couldn't ask at the time, and I assumed it was something that had dripped on an exhaust pipe or something.
 

MrCypherr

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Mk6 Wagon
Like said above, Id check the DPF sensor thats sitting on top. Seems lately that shops arent being nice with removing these sensors and have seen a couple burn up. Undo the heat wrap around the sensor and see if you notice any soot around that area, Also check the clamps on the other end of the lines.
 

MrCypherr

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If this happened right after the timing belt job, within a week, then I would take it back to them and let them deal with it. Couple of members here have had this and took it back to the place that did the work.
 

pedroYUL

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Hopefully those sensors won't burn
 

MrCypherr

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Looks like it wasnt even connected. So i guess thats a plus but I would bring it back to the shop and let them reattach it so there is record of it being disconnected incase anything else happens.
 

740GLE

Top Post Dawg
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@MrCypherr , @bmwM5power :

Yep, you guys nailed it:



It's bizarre that the part from VW is over $160, but a "new" one from eBay is $15. Counterfeit?
So this is how you found it soon as you popped the hood?

Consider yourself lucky, also amazed you didn't get a code or two. How long did you drive it like this?
 

milktree

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If this happened right after the timing belt job, within a week, then I would take it back to them and let them deal with it. Couple of members here have had this and took it back to the place that did the work.
I called them, they're going to give me the sensor. I told them I'm capable of installing it.

Looks like it wasnt even connected. So i guess thats a plus but I would bring it back to the shop and let them reattach it so there is record of it being disconnected incase anything else happens.
The nipple is broken off the sensor, it wasn't "disconnected" .

So this is how you found it soon as you popped the hood?
Not quite, I had to un-snap the silver heat shield thing to get to it. It all looked superficially fine when I first looked (with the silver shield in place)

Consider yourself lucky, also amazed you didn't get a code or two. How long did you drive it like this?
I've got about 250 miles on it. No codes.

It's *possible* that it was *barely* connected, but still leaking, until I started looking at it.

I haven't driven it since I took that picture.
 

Nuje

Top Post Dawg
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Feb 11, 2005
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Island near Vancouver
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Put site:tdiclub.com after your search terms with Mr. Google and you'll increase your odds of finding what you're looking for.
exhaust smell mk7 site:tdiclub.com gave me a number of threads. :)
 

740GLE

Top Post Dawg
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NH
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2015 Passat SEL, 2017 Alltrack SE; BB 2010 Sedan Man; 2012 Passat,
yeah i'd consider yourself lucky, could have been much worse than just a sensor.
 

milktree

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yeah i'd consider yourself lucky, could have been much worse than just a sensor.
It turns out I remembered wrong: it was more like 740 miles.

When the new sensor went in, the CEL light immediately went on.
I was at the shop when I installed it, so I had them plug their VCDS in and "do stuff".
All they did was clear the code. No special coding or anything.

It's been a few hundred miles since then and the CEL hasn't come back on. I haven't checked for stored codes yet as the kit is at a friend's house.
 

MrCypherr

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CEL shouldnt come back on as it doesnt look like there was damage to the wiring or anything like that. Looks like you got lucky on this one.
 
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