I use carb cleaner to check for vacuum leaks. Starting fluid is too volatile to be used anywhere near ignition parts.

There is a small vacuum tube under the inlet manifold of the turbo 850s that is prone to faÿlure and VERY hard to get at. Approach from the belt end with a mirror.

Another poster mentioned volvospeed.com, they have a very good page on this.

An effective way to determine a leak is to spray starting fluid on the hoses one by one. If there is a leak, the starting fluid will get sucked in and cause the engine to race a bit for a second.

Because yours is a Turbo, I woudl look through all the posts regarding rough idle, cold start problems, etc. There is a bunch of info regarding the Intercooler hoses collapsing and filling with water. That may be your problem.

Go to volvospeed.com - there is a nice set of instructions, including photos, on how to find a vacume leak.

From what I have seen, the plastic hoses are not prone to failure, although they might get clogged up under certain conditions. The rubber connections and elbows are the weak links.

A couple of troubleshooting suggestions-
*** If you disconnect a really bad vacume hose, you might get no changes in the way the engine runs - this depends on the function of the hose.
*** If you block the source of vacume to a bad hose you might get a change in the engine for the better.
*** I have seen mechanics spray water on suspect areas, the water seals small holes temporarilly, curing the problem - once again depending on the function of the hose. Some times a noise can be heard when the water is sucked into the hole.
*** Before the cooling fan operates, you could try a small source of smoke to detect a leak.

Do a search on vacume leaks, I read a decent tip on finding vacume leaks, but I forgot what it was!

Has anyone tried putting a little pressure on the vacume system and checking with soapy water? Can this harm anything?
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3 8s & 2 7s 725,000 miles total

I would be tempted to keep all the elbows and connectors (unless there is obvious damage) and just replace the vacuum lines. Why not pull a small piece of the hose off and measure inside diameter or just take it with you to the auto parts store and do a visual size match. The hose is not that expensive. You may wish to replace with silicone rubber hose for longer life; not that much more.