An observation...
With some of the upgrades we do there is an inherent side effect... thus some get the worst meanwhile others do not... I know of 18g cars with 0 issues and others with turbo leaks, maf issues, etc etc...
A lot of it comes from the improper install... meanwhile other issues arise from thinking that what you buy works 100%- often is does not.... I have seen brand new DVs leak, brand NEW turbos fail, brand new $5K clutches fail, new 1 bar springs binding on the compressor housing,flashes blowing mafs, other heat reducing kits putting cars into limp mode/ stuttering on boost.. etc etc... some of which is a install issue, operator inability to catch the problem before it turns worse... or like I said, products that simply are not 100% from the start...
just my observation.
markski

 

Everything on mine were factory parts that just broke.
Except the clutch, which just started slipping under boost in the upper gears . Wear item... yep. Earliest I've ever had to replace one on any car?... yep. Hybrid turbos so I really shouldn't give it a tick as being poor, just couldn't handle any more for sure.
DV's are in most cases preventive medicine.
Hydro wing and Slave/accumulator and fuel pump are just poor design/execution/materials.

 

Add alternator to the list of common issues. I have been lucky otherwise thus far. All I have done is alternator and clutch outside of mods. Clutch doesn't count due to EPL flash. I am sure it would have lasted a bit longer without the flash!

 

Exactly. Pointless conversation without including the mileage. A failed fuel pump or alternator @ 25k is unacceptable but it would be reasonable to expect a failure at @ 150k!

 

I put my second new fuel pump on at 19,300....
This pump has been finally upgraded by Porsche in April 09
This is my example. My car has less than 21,000.

I don't want to turn it into a bashing, just making a list of common problems we seem to read a lot about here and seeing how many others have the very same issues...

 

Great thread. Whilst the motor is pretty darned stout I do think a lot of the complex auxillary stuff has been very prone to issues. The hydraulic clutch system is a pos... The rear wing hydraulics also fail. Not if but when... Coolant hoses coming out etc... Same thing.

 

Also good to look out for the separating water hose fittings and epoxy/weld them if the motor is out for other service.

Edit: Sharky read my mind.

 

I've had.....

Faulty DVs
Blown MAF
Intercooler core failure
Exhaust heatshield bolts corroded completely

Nothing else

 

I should probably add "driving style" to that as well.

Sunday Driver
Daily Driver (always on boost , highway driving, etc.)
Race Car

This is a great thread! I've been lurking for the last few months and will be in the market for a 996tt soon. All I had read and heard until recently was how "strong" the GT1 block is etc, etc. I only thought the 2nd gear popout, dvs, and the spoiler strut were common problems.

However, Sharkster makes a good point about auxillary maintenance. These extras (hoses, spoiler strut, MAF, accumulator, slave, etc.) would annoy me considering the "lowish" mileage put on some of these P-cars.

 

How does the intercooler core fail?

 

Usually it doesn't
No one I've spoken to has ever had this happen before, so I'm definately a one off here

Basically, I had a boost leak which I tracked down to the intercooler
One of the cores had a small hole in it (completely unexplainable)

Air would enter the intercooler as usual but a small amount would leak through this hole leading to a decrease in boost pressure

This is so unlikely to happen I wouldn't worry about it
Like I said, I know of no one else that has ever experienced this

 

I blew my alternator hitting the rev limiter. ;-) Actually, alternator was good, but the voltage reg went out - it was overcharging... Not sure if high rpm the cause or just already on it's way out and that helped it along!

 

Variocam plus faulty solenoids not functioning correctly.=$$$$$$

 

Porsche has been good to me. They replaced my transmission under warranty, at 4 years
and eleven months of ownership. A fuel level sensor failed, front transaxle rebuilt, and the
clock gains 5 minutes a month... 20,000 miles so far. ANd I have that Spanish guy Manuell
managing my air conditioner.

I replaced the clutch too, but I attribute that to my reprogramming for extra power.
Some have had shift linkages break. I have not, but did replace them early with
better EVO parts. And don't forget the diverter valves that every one seems to
replace or blow.

I bought mine new in August of 2000, one of the first in the country. Later ones I
hear already have the stouter steel synchros.

 

What years are these 996tt's? I was thinking of a 2004-2005 as my next DD but after reading some these annoying issues I may rethink the purchase.