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2002 Audi TT 225
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Discussion Starter · #1 ·
Since I bought the car almost a year ago it has had what I believe is an exhaust leak. Its comming from the front right of the car behind the wheel, I have looked at every 1.8T odd sound video I could find but none were like mine. It starts out quiet on cold starts and quickly becomes louder as the motor heats up, which doesn't make much sense because if everything expands with heat I would thing that it would become quieter. Any help is greatly appreciated, thanks.

 

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Sounds like top end chatter to me, not an exhaust leak. Exhaust leaks smell bad and cause Check Engine Lights in our cars unless you're chipped.

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Discussion Starter · #5 · (Edited)
Sounds like top end chatter to me, not an exhaust leak. Exhaust leaks smell bad and cause Check Engine Lights in our cars unless you're chipped.

Sent from my motorola edge plus using Tapatalk
Also, sorry, by chatter do you mean the whistling sound or the knock at the top of the motor, because the highest quality gas at the pump here in Utah is 91, and I think I may need to start using octane booster if it is pinging and knocking, or it could just be worn components for all I know
 

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I daily drove my stock tuned TT on Utah's 91 octane for a decade. I doubt the gas is the problem.

I tried listening for "chatter". On my phone's speaker, all I hear is the standard cold start tap. You may want to pull up measuring blocks 14-16 and see if misfires are being detected.

There's a vacuum reservoir for the EVAP purge valve under the passenger side wheel well liner. I don't know if that can leak and not throw a code.
 

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Discussion Starter · #7 ·
I daily drove my stock tuned TT on Utah's 91 octane for a decade. I doubt the gas is the problem.

I tried listening for "chatter". On my phone's speaker, all I hear is the standard cold start tap. You may want to pull up measuring blocks 14-16 and see if misfires are being detected.

There's a vacuum reservoir for the EVAP purge valve under the passenger side wheel well liner. I don't know if that can leak and not throw a code.
First, thanks for the EVAP tip, I am going to try pulling some part off and see if I find anything, or if not, I will try a general leak test. The clicking though seems fine, it's either the cold starts, or simple valvetrain noise.
 

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I hate to send someone down the rabbit hole of the vacuum system. Once you start digging into the vacuum, fixing one leak will let another go. Going back to your video, your tach at idle looks high to me. On a stock tune, it should be pegged at 1000 on start up and drop to 800 after the SAI pump kicks off. The ECU will raise the RPM a bit to compensate for some vacuum leaks before triggering a CEL. That could also account for some of the extra noise.

If you're going to start chasing vacuum leaks, I highly recommend you order a stock of high density silicone hose in 4mm, 6mm and 8mm inner diameter and oetiker/ear clamps to match the outer diameter. On my last round, I picked up the Autobahn88 stuff on Amazon and it's been great so far. It doesn't collapse like the crap you get at Napa/AutoZone/OReilly.

Also be warned, the off the shelf Doorman connector pieces those places sell don't work with metric hose. In a pinch, OReilly does have vacuum connectors that fit in their back room. Find the stock numbers for the pieces you need on their website before going in. It'll save you some headache.

Another thing you might want to consider having on hand are some check valves. I don't have the part number handy, should be easy enough find on 7zap. For the control valves (EVAP, N112, N245 and N75) I wouldn't replace them unless you know for certain they are bad.

As you dig into it, don't be surprised if your PCV breather is shot. The nylon hose just under the intake splits over time and the venturi valve / vacuum pump will gum up. If you do go for a refresh on your breather, do yourself a favor, spend the $5 for an intake gasket and take off your manifold. Much easier to get at the mess and you'll be able to inspect your injector seats for cracks (another leak point).

Happy hunting
 

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Discussion Starter · #9 ·
Thanks, again, tomorrow I am going to take the wheel off and inner fender to take a look at things, see if I can find where it is exactly coming from. And with the idle, it is very jerky along with being high, and performance is for sure more sluggish than it was before. One thing I have found is bad PCV valves being one of the culprits, but I will just have to do some digging and order some new valves. I am doing the plugs and coil packs here soon too to help with misfires and sluggish performance.

Thanks, and if/when I find anything I will update here.
 

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Discussion Starter · #10 ·
Update:

I finally thought that I had found the problem with the vacuum system, from what I had taken apart and looked after last week it seemed to me that it could be the secondary air injection pump. But just to make sure I wanted to confirm that with my mechanic before I dished out 3-600 bucks for a new pump. I got the car back Friday night and he told me that it was a very odd sound that he had never hear in a car before, and long story short, they took a few things apart and when they took the timing belt cover off it was extremely loud. He thinks, and it makes sense to me, that one of the tensioners for the belt is shot. So, it looks like I am going to tackle the timing belt and everything else here pretty soon. One thing though, that still doesn't explain the idle issues, but i'm going to try new coils and plugs when I do the belt too.

Thanks for the help though, and I hope I don't blow the motor with the belt job:)
 

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Update:

I finally thought that I had found the problem with the vacuum system, from what I had taken apart and looked after last week it seemed to me that it could be the secondary air injection pump. But just to make sure I wanted to confirm that with my mechanic before I dished out 3-600 bucks for a new pump. I got the car back Friday night and he told me that it was a very odd sound that he had never hear in a car before, and long story short, they took a few things apart and when they took the timing belt cover off it was extremely loud. He thinks, and it makes sense to me, that one of the tensioners for the belt is shot. So, it looks like I am going to tackle the timing belt and everything else here pretty soon. One thing though, that still doesn't explain the idle issues, but i'm going to try new coils and plugs when I do the belt too.

Thanks for the help though, and I hope I don't blow the motor with the belt job:)
I'm pretty sure I had the same problem on my 2000 180 Quattro. My car has the K04-001 upgrade which uses the stock 180q exhaust manifold. I do have an upgraded down pipe.

I had a similar ticking noise that varied with RPM, so I assumed it was the alternator pulley or tensioner pulley. I replaced those and the serpentine belt with no change.

After much frustration, it turned out that one of the three bolts vibrated completely loose. The other two were slightly loose and the threads nearly worn off where it passes through the manifold. The exhaust gas leaking through blew out the gasket worsening the the leak. This created an RPM dependent exhaust leak.

Because the parts are not solidly fastened together the heat likely softens the parts and allows the gap to expand where the bolt is totally loose.

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They've been replaced (by necessity) and replaced with the hardware specified in the Audi parts catalog. I think there are two different options in different model years of the car. One of the options uses bolts that appear similar.

I applied copper anti-seize this time - it apparently bonds with the zinc on the bolts and the turbo housing, preventing them from rattling out, and withstanding the crazy temps. I'm pretty certain none was applied previously with this result.
 

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Discussion Starter · #14 ·
Update again:

After attempting all of Saturday and last night until midnight, I finally got the belts and pulleys put on the car and the engine back in. After a worrying first start, the noise is completely gone, I think that it was the little roller on the bottom of the old hydraulic tensioner that was the problem. Those stupid engine mounts were the biggest pain in the butt I have ever dealt with though, and now I just need to burp the cooling system and I should be good to go.

Thanks again, will be around somewhere with new questions at some point. (y)
 
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