Car Info: 115,900 miles. 1.9 turbo automatic s40. no modifications.


Under my car there is this part of my exhaust with what looks like a woven cover. The pipe connected to one end (the end that later goes to the catalytic converter and then the muffler) is not connected anymore, I can't tell if it just was welded on or held on by something. Anyone know anything about this section of exhaust? I'd really like to know what the woven thing is.

 

The "woven thing" is called the flex pipe, and it connects the catalytic converter side of the exaust (the rear section of the pipe that goes from the flex pipe to the catalytic converter) to the front section of the piping that goes forward from the flex pipe to the "preconverter" unit. Forward of the preconverter unit is the exaust mailfold. The flex pipe rusts out eventually and needs to be replaced. You can have it re-welded, but this is a poor solution, since the welding has to be well done (a shop that does decent welding work will charge $50-$100 to do it). A poor weld job will just come undone soon. Even a good weld job is really just patchwork, and it could leak. The best solution is to replace the converter. The converter will come with the whole pipe section, that includes the flex pipe, and you simply unbolt the old pipe section and install the new one. I just did this myself on my 2000 S40. The aftermarket part cost me $180. You have to get a new gasket for the front connection ($10). Watch out in taking off the 4 nuts from the front connection. Spray some WD40 or other loosening substance on the nuts and let it set in first before trying to remove them. The job took me a few hours, total.

 

thanks for the help, I was able to get the flex piece replaced. I am thinking about replacing the whole system soon, because it's all looking pretty nasty, and I don't know how well this new piece will hold.

one question though, it looks like the flex pipe is a bit smaller in diameter than the original piece, is that something i should look into?

after having it replaced I noticed some noise from my turbo, (whine, wistle, winding sound, no scraping or anything, only when driving, when revving I can't even tell there's a turbo) and figured I just never heard it before because the exhaust was louder. Could this peice be causing pressure issues for my turbo when driving, making it leak or whine? Or does the s40 make a little bit of noise with its turbo?


Figured I'd just ask along with the wrest of it cause you seem to know a thing or two and you actually own an s40 that has probably the same engine as mine. I know the transmission in mine is different, and a few other things, but I'm pretty sure the engines are the same.

 

Hi there. It is ok if the flex pipe is a little smaller. The replacement Catalytic Converter I got also had a new pipe that was slightly samller than my Volvo original. Performance will be fine. Your turbo whine is likely because you can hear the engine better now, and there should be no real increase in back pressure from the new flex pipe, so I would say you are safe.

 

Thank you for the reply. That's what I was hoping, that it just sounds like that and I can hear it now. I ran into a mechanic at Auto zone today and I asked him if he could take a loot at my system, and he said it all looks and sounds fine, and that the sound can only be heard well in the cabin when putting out torque, so it's nothing to worry about. I've never owned a turbocharged car, so I've been overly paranoid about it for a while.

In the back of my head i was sort of thinking about how having a bad turbo could maybe not be as horrible as it sounds, cause then I'd have a reason to upgrade to the 14t for a couple more horses under the bonnet . Replacing them is pricey, so I'll just wait until I have no choice.

and once again, thank you for your help.