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PassatWorld Staff
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Discussion Starter · #1 ·



This gasket came with my Random Cat (vendor-supplied, not Random). It's the turbo outlet gasket. Note that it has no metal compression ring around the inside of the hole. It has taken about 8 months for this to go bad.

I had ordered the VW gasket (which does have the compression ring) but it hadn't come in when I was ready to install the Random Cat, so I went ahead and used this gasket. I discovered the leak Saturday, pulled out the VW gasket and had it in Sunday. Whew! If any of you have used a non-ringed gasket, go ahead and get a ringed one, you'll need it someday...

Heat Shield Sunday 7/6 before gasket gone bad:


Heat Shield Saturday 7/12 after gasket gone bad:
 

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PassatWorld Staff
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12,264 Posts
Discussion Starter · #4 ·
Ween2004 said:
Did you have any symptoms besides the heat shield melting? I am in the process of trying to find my boost leak and read somewhere that this gasket can fail causing low boost.
Well, I didn't see the heat shield until after I pulled it off. The symptom was that I heard exhaust noise in the engine compartment. I had been hearing it for several days, but only in my garage so I thought it was a weird echo. It finally got loud enough to get my attention.

This won't cause a boost leak - it's on the exhaust side of the turbo. It won't cause any loss of boost, but it will make your car run non-optimally. The fuel trims get out-of-whack trying to compensate for this. And it's a lot of hot air near your airbox.
 

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PassatWorld Staff
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Discussion Starter · #6 ·
Ween2004 said:
... not allow for proper back pressure causing the turbo to not spool up properly.
Is this an "urban legend" or something? I hear this so often (not fussing at you, Ween) that it makes me sick. Just thinking about it from basic Newtonian physics tells anyone that it doesn't make sense. Backpressure makes turbos slower. Elimination of backpressure is a GOOD thing. When my cat separated from the turbo outlet flange, I had more boost than the ECU could handle.

What turbos DO need is smooth, uninterrupted flow. Having an exhaust leak near the turbo reduces the backpressure (good thing) but introduces turbulent flow, interferes with accurate O2 sensor readings, puts hot air into the engine compartment, and GOK what else that screws with good power.
 
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