2002 Saab 9-5 Arc (3.0t V6) Problem

[cynicaldriver]

I have recently been having an issue with rpm consistency. What happens is the rpms and boost both surge randomly. Sometimes it is a couple times a minute, sometimes it's a constant surging and stalling, sometimes everything is smooth as silk.

This problem seems to be most prevalent under idle, while in gear at a stop. Once in a while it happens at driving speeds (which is especially disconcerting) but not usually.

There has been increased oil consumption, and coolant burn. The coolant problem may be exclusive to the leaking thermostat housing that I am also replacing, but I cannot be sure.

Upon tearing the intake off the engine, I discovered that there is oil in the intake and fuel sending unit (where the throttle cable is attached.) This suggests an intake gasket leak, but the gaskets are fine... So I tore further in.

After removing the turbo intake I took a look inside the turbo. The Turbo is taking on oil from outside. Now, what I need to know is...

Do I need to replace the entire $140 oil pressure block (1st picture) or something else?

Also, can someone help confirm my thought about the oil coming in before the turbo? Pictures provided below.

I will be rebuilding the turbo either way, but I would rather not replace the block in picture 1 if that's not the sourse of my problem.

Pictures:
1) Oil Pressure Block? (Part 90 490 560)
2) Turbo intake manifold top port (air)
3) Turbo intake manifold port 2
4) Turbo intake manifold port 3 (oil)
5) Turbo intake manifold bottom (turbo)
6) Turbo from exposed intake side
7) End of pipe coming from block (pic 1)

[cynicaldriver]

Closing this out, as I have rebuilt the turbo and cleaned out the oil pressure control valve.
I also replaced the engine coolant temperature sensor and the thermostat, along with the intake gaskets all around (since you have to disassemble that to get to the thermostat anyway.)
This seems to have solved all of the problems related to the idling and running of the engine.

I will be making a new thread for another issue that has arisen after fixing this issue.
If anyone finding this thread through Google or Bing see's this, take the time to rebuild the turbo. It is actually easier to rebuild it than it is to remove it and put it back on. It has improved the boost and reduced the turbo lag quite a bit, and is a MUCH cheaper option than replacing the turbo with a reman or aftermarket part. I picked up a kit for about $60, which was a universal kit for the Garrett turbos (15, 17, and some higher.) Do NOT be afraid to do this yourself, as it is pretty straight forward and will save you hundreds of dollars... Provided you have the tools and ability to remove it and put it back on.

If you are taking this to a shop, ask about having them remove it for you and putting the car aside for a few hours while you rebuild the turbo yourself. It will actually only take about 30min, including cleaning. Just make sure to keep track of where everything inside the turbo goes and don't miss any of the small pieces. Around here, shops charge up to $400 to do the rebuild, and that is not including removal and re-installation.



That is what my intake side of the turbo looks now. I forgot to take "after" photos until we had it reinstalled, and I apologize for that, but this will give you an idea of what some brake cleaner and a toothbrush can do for internal parts when they sludge up and need cleaning. The shops WAY over-charge for this work, and I am seriously considering offering the service now, as a side-income. There is also zero "play" for the impeller shaft. It is like new, except the couple discolorations from the length of time that the sludge had built up.