I've never known anyone to remove and clean turbo lines.
The return to the block may need to be gasketed at the turbo and O-ringed at the block...you have to remove the oil filter to get the tube out. Two bolts into the turbo. Watch them, different lengths.

The oil feed line to the turbo is generally best left alone....it may or may not have coked oil deposits in it and if you remove it or bend it or flex it they will loosen and may jam the oil feed hole to the turbo bushing. Death.

Read the FAQ at the BB opening.

I've never heard of cleaning specific coolant lines either, although I guess you could run a heavy duty flush and then a lot of water through the system.

If you don't know what's been done to your 89 you could consider changing out the timing belt, front seals, V-belts, upper and lower radiator hoses, and heater hoses, but that can get expensive.
Ditto for the turbo hoses, especially the intake from the amm to turbo.
Go through the entire vacuum hose system and replace those old things...they'll crumble in your hands if they're OEM and 12 years old

Check/clean the throttle body and the IAC valve.
Check/clean the PCV system, especially the nipple on the manifold the small hose comes from going to the PCV elbow and the small nipple on the PCV elbow. The larger holes on the PCV elbow have also been known to clog...takes a 3/8" drill bit spun by hand to clean out the large hole and a, what, 1/8" drill for the smaller hole.
There's a box on the intake side of the engine, below the intake manifold, difficult to get to but can also require replacement.
Consider checking valve clearance and replacing the cam cover gasket.
Switch to synthetic lubricants in the rear diff, transmission, and engine.
Use Volvo or Mercedes coolant in the engine.
Replace your coolant expansion tank cap (unless it's already been replaced...shouldn't be black).
And last but not least, consider replacing your radiator if it's OEM plastic and 12 years old...it doesn't have much life left in it and when it goes the radiator neck will crack or a side tank will go, right when you need it most.