In the first pic with the white nylon hose it was going to a catch can made out of a high pressure air filter mounted near the washer bottle on the driver's side. It worked as an oil separator but the long thin hose made too much pressure in the crankcase and the dip stick would pop out after high revs.
https://i.imgur.com/TNkfcMv_d.jpg?ma...&fidelity=high

I gave up on the catch can idea and went with a much shorter routing to the air box with larger diameter hose. This setup has been much more reliable.
https://i.imgur.com/0XZ98Of_d.jpg?ma...&fidelity=high

https://i.imgur.com/2OltI59_d.jpg?ma...&fidelity=high

If an intake manifold looks as restricted as the one shown in tjts1's images, then don't you have to be concerned with cleaning out the cylider head above the valves? Those intake runner paths continue into the head, right?

It's amazing what you can do with a can of brake cleaner and a bent butter knife. Just make sure the valves are closed lol.
https://i.imgur.com/sy291SB_d.jpg?ma...&fidelity=high

I warmed my engine up by running it with the manifold off. I then shut it off and used a spoon shapped spatula to reach into the head and shovel the softened gook out. I didn't worry about the position of the valves. I could feel the valve stems. I just kep on until I could get very little out. With 12 of them it will keep you out of trouble for awhile. The gunk is mainly from the EGR. The oil from the current breather system helps stick the soot, but stopping the soot would be my approach. The oil into the head from the breather might be good as lube for the intake valve stems.

When you work on the fuel lines, don't forget the shut off valve. There is an o ring ($3 part) between the shut off valve and the injection pump that often causes problems and should be changed. Also, inspect the plastic shut off valve carefully. Mine was cracked and I think resulted in a small leak for several years. There is also a banjo bolt on the shut off valve that you have to remove to change one of the plastic lines; that has a small lime colored o ring on it that should be changed and is sold separately from the plastic lines. There are a couple of washers on the banjo bolt that should also be changed.

If you buy your fuel lines from a dealer, ask for a print out diagram of the lines. That will show you all the parts of the system.

Here are my records (attached) from stamps in the maintenance book and print-outs from the dealership where I bought the car. Lots has been done. We'll see if things fail as much now that the car is being used quite a lot more. I think averaging 5,000 miles/year is not good for a diesel!

I assume I'm the third owner. First owner bought & serviced the car in Florida. Second owner brought the car to Ohio in February 2005 and serviced it at the dealer. Now it's mine and will nearly always be serviced in my garage.

I'm going to do the 90,000 mile service in the maintenance book and just go on schedule from there.

Work I plan to do in September:
- 90,000 mile service: Replace motor oil & filter, tons of inspections
- Extended service: Replace fuel filters (pre-filter and main), engine air filter, cabin charcoal filter, clean & lubricate windshield wiper, clean & lubricate sunroof
- Flush coolant, replace all coolant hoses
- Replace/repair degraded wiring in headlight housings
- Replace broken third brake light housing
- Clean intake runner & manifold
- EGR delete
- Replace valve cover gasket
- Replace tires

After all that, I'll go back through all your suggestions and set priorities, and open threads for specific issues.

Thanks for all your help!

Quick update. I'm sure you've been dying for this, wondering what the status is! :-)

I've done:
- Engine oil & filter (needs done again).
- Engine air filter.
- Cabin paper air filter.
- Cabin charcoal air filter.
- Replace headlight wiring.
- Replace tires (got Michelin Primacy).
- Replaced 3rd brake light housing.
- Replaced broken fog light lens and some parking/indicator bulbs.

Parts purchased, waiting to go on.
- Coolant hoses.
- Power steering rack boot.
- Motor & transmission mounts.
- Oil sending unit.

It's nice, making something better.

How much oil gets to the air box?

I don't know, I've never looked lol.