Hopefully someone can answer this. I was replacing the exhaust manifold gasket on my 2007 S40 T5 and found a broken stud on exhaust port 3. I was able to pull the manifold back enough to get a pair of vice grips on the stud remains and back it out. I had to do this all by feel and could not see the stud. Unfortunately the stud slipped from my grip and dropped. I heard it bounce and ping but could not find it anywhere. I'm worried that it fell into the exhaust manifold and to the turbo (yes, I know I should of taped over the ports but too late now). I spent about and hour with a snake magnet down the manifold all the way to the turbo but never found the stud. I'm doubting it actually fell in but, obviously, want to be certain before I button it up..

I put a small endoscope down the manifold and can see the blowoff valve but can't see the turbine at all. How exactly does the exhaust get routed to the turbine? A breakdown diagram or similar would be very helpful.

How narrow are the exhaust feed passages to the turbine? I'm trying to figure out where a stud could be hiding. Could a stud work down through the passages to the turbine itself? I can still freely spin the turbine from the exhaust side.

 

I doubt you would have heard the "bounce and ping" if it fell into the exhaust manifold. My guess is it's hiding somewhere in your driveway / garage floor.

 

I agree with Habby. If you still can't find the stud, I'd look for turbo rebuild/replace vids on Youtube to get an idea on how the parts mate up. but there's really not much to it - the turbo bolts into the exhaust mainfold. It has two sides - the exhaust header feeds one port to spin a turbine that in turn spins a shaft to the compressor wheel so there's no real way for the stud to get into anything deep. At worst case you should be able to separate the turbo from the manifold and look into the port - I'd think something as large as a bolt would be easy to spot.

 

You guys were right. I found the stud hiding under the manifold. It's all back together now. Unfortunately the manifold leak was just part of the noise. I still have a loud 'rumble' on hard acceleration. I'm thinking its the flex pipe now.

 

if you can slide or reach under the car when the engine is running (lol, not advised but I've done it), you should be able to feel and hear the air puff out of any holes around the flex pipe. Fixing the flex pipe can be costly since its may be part of the catalytic converter. Plan B would be to source the flex pipe section itself and have a shop cut/weld into your existing cat. You may want to measure the pipe diameter and lenth of the flex pipe and check Volvo friendly sites or eBay/Amazon etc. to see if you can fine a coupler that fits.