This hose has broken on my S80. Looks like something for crankcase ventilation perhaps? It is extrememly brittle. It comes out the top of the valve cover and bends over the front of the motor, heading down to where I dont' know.

Question: what is it called and where does it connect at the other end? For the time being I've duct taped it together, hoping I don't throw a check engine light.
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'94 945t

I have never seen one break before. That is the crankcase ventilation hose and it connects to the oil separator below the intake manifold. Unfortunately, to replace it you probably need to remove the intake manifold to get access to the bottom of the hose.
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My name is Klaus and I am a Volvoholic.

Klaus: thanks for confirming my suspicion. What do you believe is the downside risk to leaving as is or repairing with duct tape?
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'94 945t

Back in the good old days, the crankcase was vented to the atmosphere. The enviromentally responsible engineers designed a closed crankcase venting system so that the gasses get burned in the cylinders.
Your duct tape solution will probably not work very well due to the high heat and oil residue, so watch out for the tape falling off within the next 1,000 miles.
You could order a new pipe, remove the manifold carefully so the gasket is not harmed, and replace the pipe. Just remember that it will be a 3-5 hour DIY job.
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My name is Klaus and I am a Volvoholic.

hopefully there is a picture on this message!
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'94 945t