2000 Volvo S80 Twin Turbo Issues
 

I now just about enough cars to be dangerous but not enough to know what I am doing. I have perhaps the highest mileage S80 out there. My odometer stopped working several years ago and it still reads 233,000. As nearest I can tell I am at the 400,000 mark.
I have always had minor issues with the warning lights on the dashboard. My ABS light has been foreever and the check engine light has been too. Had it had the Volvo dealer who told me it was an O2 sensor issue, but yet they could not fix it. Then the ABS light came on and I attributed that to the wheel bearing needed repalced in front and the ABS sensor being in the Hub.Car has always, as far back as I can remember, sound like a vacuum leak or something.
About a year ago I dropped a couple of cylinders and found out it was due to the igition coils going bad. Paid a hefty price to replace a few and the issue went away. About 6 months ago I dropped another one and paid another hefty price to replace. About a month ago I dropped a couple more but only this time I was tired of paying somone so I took it on myself. Wasn't in that big of a rush so it took me about a month, plus I did not know which ones were bad. I figured it out by figured out how to FIND the coils, then starting disconnecting them one by one until the two that did not change the tune of the motor when disconnected. Had all kinds of tubes that run across the top of the motor disconnected that I have no idea what they are. I had the motor running with the tubes off while I found the bad coils. Had a hard time as the motor wanted to stall without the tubes connected.
Replaced the coils and put her back together. Today was the first day in about a month that I drove it. Ran fine on the way to work (90 minute drive.....where do you think the miles came from?). Or I should say I did not notice anything on the way to work. Leave work tonight to come home and the dreaded "no oil pressure" light comes on. I stop and check the oil level, yep, that is fine. Unscrew the oil cap and I can see that oil is getting in that area that I can see so I assume a sensor and continue on.
Get home and start researching and find all of the wonderful things said about this car and the oil pan o rings. Trying to talk myself out of this issue being the issue. Worse yet, this does not sound a project I want to take on myself.
Could I be missing something? What are all those tubes running across the top of the motor? Is it possible I did not reconnect one or more them properly?

The tubes going across the top of the engine are for the turbos, 2 larger ones are from the MAF sensor/ air filter to the turbos and the plastic peice that Y's in to one peice in the middle are from the turbos to the innercooler. None of these being connected wrong or loose or not at all can cause an oil pressure issue.

The "low Oil" message also occurs when the pvc system needs to be cleaning. When is the last time that you had this done?

How's your idle? You'll get the low oil message if the car is idling below 750rpm.
If yours is, then you may need to clean/replace the ETM.

Both of these issues are seen in high mileage S80s, like yours.

I have never cleaned the PVC System. Care to share the details of how to do this? Is this something I can do myself?
Important to note.....the message is "No Oil Pressure" and not "low". Does this make a difference?
What damage will be done if I keep driving?

Ok so some folks will call me stupid here but I really didn't have a choice.
I have continued to drive the volvo even with the no oil pressure light on. 90 miles to work this morning and I think I almost did not make it and now have some serious issues. The entire trip is highway at 70 MPH.
First 20 miles went with no issues, no oil pressure light or any noise.
Next 10 miles the no oil pressure light would flash, not a flashing like a warning light but rather on for 10 seconds then off for 20 then on 5 then off for 30, etc.
The the light stayed on. At about mile 65 of the trip I noticed a wierd sound coming from the drivers side of the engine. Sounded like a vacumm and you could hear it then it would make the final suction noise and you could hear it close. This went on the remainder of the trip.
At mile 70 while headed up a hill I noticed a pluff of white smoke from the tailpipe. From that point forward I knew I was in trouble. Stop and go traffic for last 10 miles of trip and major white smoke when I stopped. Once up to speed the smoke was not visible. I could also hear a strange sound from the motor. Kind of like a screaching sound.
Like I said, not much of a choice here. Even if motor is fatal with the age and the cost to fix it the Volvo was not getting it done so I figured I might as well take my chances and keep going till she dies.
Thinking back I did put some addictivie in the crankcase that I got at the auto parts store the day the no oil pressure light came on. Guy said to expect some white smoke for first 10 minutes. Could this be the issue and if I just drain the oil it will go away?
Anybody want to buy a cheap Volvo?

Decoding Tailpipe Smoke Colors
 

For what it's worth - tailpipe smoke:
- bluish means you've got oil in the combustion chambers
- black means you've got excessive fuel in the combustion chambers
- white means you've got water in the combustion chambers

I don't know what all is wrong, but "no oil pressure" indication, followed by driving it anyway, followed by loud screeching and other odd engine noises - doesn't sound good at all. I suspect something dramatic may have happened, and you probably don't need a factory Volvo mechanic to diagnose it.