Car has about 2200 miles and has run flawlessly until today. Canyon run, 92 degrees temp, sport plus running it in the 4000-6500 RPM range. After an hour of running, I punched it out of a turn and heard a pop followed by a noise that sounded like the muffler was dragging behind the car. The noise went away and the car ran ok as long as there was 0 turbo boost. A loud mechanical grinding noise accompanied any turbo boost above 0. Had to drive home with very little throttle input.

Disappointing to say the least. It lacks the punch I like out of turns as it is and for this to happen....

Anyway, going to the dealer tomorrow.

 

sounds like a popped intake or intercooler hose somewhere, not that uncommon on the 997's.

 

I would say do a boost leak test. But that's a huge hole and can be seen. I also vote for intercooler pipe.

 

Dealer thinks it's a popped intercooler hose, which is listed as a potential issue in one of the five service bulletins for the 991 TT. Unless their suspicion is wrong and another problem is found, I should have the car back tomorrow.

 

Loud mechanical grinding noise? That doesn't sound like a loose coupler or popped intercooler end tank.

 

Had an intercooler hose pop out for me several times with my previous 997. In my experience, there wasnt any grinding noise but on any throttle input you would hear a very loud swoooosh sound from the turbos but no kick (as if the engine wasn't being boosted). Once the car comes to a halt the engine would shut-off immediately with CEL light showing.

 

What are the five service bulletins for the 991 TT? IC hose coming off is one, what are the other four?

 

Ugh. My car is still at the dealer since last Monday trying to figure out the boost leak problem. No CE lights, either. Boost goes up to 2-3PSI and then a whooshing sound, that's it. Dealer is stumped, they've done all the service bulletins on the car. They thought it may have been the fabspeed exhaust but they took it off and checked it out and put it back on, it's unrelated. BC991 had the same issue and said it was fixed by his dealer but he hasn't been online to respond to my PM, so I don't know which dealer and service tech did his repair in orange county.

 

Make sure they're doing the boost leaks tests with the rear bumper off so they can inspect the y-pipe and other lines that are hidden behind the bumper.

Do they have a smoke machine? If they're just visually checking, they'll end up chasing their tails for days. Sometimes it could be a hard plastic part that's cracked which you wouldn't really notice unless you can pressurize and smoke test the system.

 

Your experience is very similar to mine, loud noise after 2-3PSI. They are also sourcing a low rumbling noise coming from the rear drivers side. I'll know more today.

 

Thanks for the advice. I'll ask the service tech.

 

The service tech stated that the intake leak is a known problem and indicated in one of the service bulletins. Not sure is this makes it easier to find or not, hopefully it helps them identify the source and fix it quicker than not.

 

Keep in mind...if the sound is like a "whooshing" or is obviously just the rushing of air, it's a boost leak somewhere, and if you can hear it like that it should be a pretty obvious one.

But if you're actually hearing a mechanical grinding sound...I would have them check the turbos as well. The infamous "dentist drill" sound is generally the sound of a failed turbo...

 

It definitely didn't sound like the dentist drill. More of a whooshing with some mechanical as well. The service manager did a ride along and felt it was the intake hose after hearing the noise.

 

Did you get a CE light? Did the dealer pull any error codes?