Saving Christmas trip - turbo intake pipe hack

Hey folks. Family headed to the keys for a quick Christmas vaca. Boat was running great until just north of Stuart we heard a sucking/whistling sound and saw black smoke coming from port engine. Exhaust smoke also coming from port turbo. Done for the day, we limped into Stuart to anchor.

Went down to the engine room and discovered a part Volvo calls an “intermediate pipe” between the turbo and aftercooler elbow seems to have come dislodged. According to the parts diagram, it is a short straight pipe with a flange in the middle and two sealing rings (o-rings) on either side.

I have to wait until the engine cools down a bit to disassemble things and see if the part is broken or perhaps if one of the sealing rings is damaged.

But this trip is only a week and I’d really like to keep going if possible.

question is - can I just fit a piece of exhaust hose (assuming I can find the right size) over this joint and clamp it down real good and call it good enough to make it to marathon (another ~200 nmi)? I’m nervous if I have to order and wait on a part we’ll be stuck here for days, to the point it won’t be worth going any more.

I don't see how the cooler inlet could have moved since it's got six bolts holding it on but I take your point. What's extra weird is that I have an exhaust leak on the stbd engine as well that started about the same time. Though that leak seems to be coming from the joint between the turbo exhaust and exhaust elbow. None of this stuff has been touched in about 30+ hours of running.

First order of business is to try to find a slip or dock I can tie up to in the morning, and pull the cooler elbow off so I can see what's going on. I'll also see if the turbo compressor could have rotated somehow.

Well it should come as a surprise to no one that you were right Ralph. Once I could get in and get a closer look I found two of the four studs on the hot/turbine side of the turbo that should be securing it to the exhaust manifold are completely loose. It appears they had been secured with a flange nut instead of the nut-spring washer-washer combination Volvo calls for. One of the nuts had rattled completely off and both studs are completely backed out of the turbo. I believe that’s actually where my leak is coming from.

The problem now is I can’t get the studs back into the turbo housing. I’ve been trying for an hour and I can’t get them to twist in. I’m hoping I don’t need to remove the whole turbo - maybe just need to loosen the studs on the other side?

At least I’ve found the smoking gun…and I found the nut…

I think I’m gonna call this quits. The more I look at these studs I think at least the bottom one is actually broken off inside the turbo housing. If you look at the picture closely you can see the nut on the bottom stud has about 1 thread protruding from the top. But I can press the nut and stud firmly against the housing, pressing the stud into the hole, and it still spins and wobbles and doesn’t engage. There should be enough length on that stud to engage 3-5 threads in the turbo housing. If there were I wouldn’t be able to push it in so far and spin it freely. Seems most likely, for god knows what reason other than it was our one family keys trip for the year, those studs sheared and snapped.

so…I’m going to find a place down here to get the work done. I was due for a bottom job anyway. I’ll just look on the bright side - instead of thinking of it as missing my vacation, I’ll think of it as getting an early start on maintenance!

appreciate all the help, you guys are great!

Yes a previous tech installed flange nuts instead of the spec’d combination of nut+spring washer+washer. This was the same person who wired my alternator backward and messed up my Bahamas trip last summer. I’m not sure if that was part of the problem but there’s a little recessed inset in the exhaust housing flange where the washers would sit snugly. Instead this flange bolt was lodged against the housing but not in the recessed area. I have a suspicion this caused a shear loading in the stud that eventually led to a crack, propagation, and ultimately high cycle fatigue failure. This would explain why it was fine for dozens of hours but ultimately failed right at the time it could ruin my vacation because that’s the true meaning of Christmas boat trips.

It’s just a theory. My other theory is, boat.