I recently had my 997.1 modded with GMG exhaust with 200 cell cats and an FVD tune. My car had about 14,500 miles on it so I had the spark plugs replaced at the same time. I drove the car from Dallas to home which is about a 5 hour drive with no problems. I probably put another 50 miles on the car driving around town with no problems. Last weekend, I was making a full throttle run through the gears and heard a pop followed by hissing at about 4000 RPM in 3rd gear. I immediately lifted and drove about 2 miles home. I figured an intercooler hose or Y-pipe connection had come loose. I jacked the car up today to look around and can't find a loose hose anywhere. I checked the connection at the turbos, the bottom of the intercoolers, the top of the intercoolers, the ends of the Y-pipe, where the Y-pipe enters the throttle body, and where the intake manifolds connect. Every soft hose connection I can think of or see. I couldn't see all parts of the hoses very well, but I felt and squeezed what I could with my hands and pulled on everything and nothing would slip loose.

After checking the hoses, I drove the car and there is still a strong hissing sound that increases with boost pressure. I'm still able to get 15 psi boost on the gauge in the car while accelerating in 3rd gear. Sitting in the driver's seat, the sound seems to be coming from the right rear of the car. What else should I check?

 

definitely still a boost leak... the y-pipe that connects to the top of the right rear intercooler could be loose. the hose sometimes seem like its on tightly but unless you hear the click or snap when you connect them its not fully engaged. HTH

 

Yep, pull the Y-Pipe towards urself. Bet it's loose, had the same symptoms...hissing ect.

Ken

**edit** give it a good tug.

 

Great advice guys! I gave the Y-pipe a good tug and the hose slipped loose from the top of the intercooler. Now, can I get to the top of the intercooler by removing the brake light housing or does the bumper have to come off?


Edit: nevermind, got it back on. For future reference, you can't get to the top of the intercooler from behind the brake light. You also don't need clear access to the intercooler to reinstall the hose. Just put the hose back on through the hole in the inner fender. I had a hard time getting the hose to "click" in so I removed the Y pipe for a little more room to work. After that, I still couldn't get the hose to click in, so I put a little bit of silicone lubricant on the o-ring and it clicked right in. With the lubricated o-ring, I probably could have reinstalled the intercooler hose without removing the Y pipe.

This brings me to my next question. When I removed the Y pipe, there was a fair amount of oil sitting in the rubber hose that connects the Y pipe to the throttle body and in the throttle body. Is this normal? If not, any idea on what could cause this? I had my oil changed a few hundred miles ago when the other mods listed above were done. Picture below.

 

Yes- very simple fix, use some heavy-duty thicker clamps in replace of the stocks

 

Completely normal