So , I have a thing for old Buicks. And a 2008 Lucerne CSX came up for sale locally cheap. And a guy needs a car, so I thought I could flip it fairly easy. But this northstar leaks so much oil, it is ridiculous. And its packed in there like a sardine. So if it's the block girdle or rear main seal, I ain't bothering with it. But what of the other easier to get to or less expensive leak points? N* Fellow sufferers, what are your thoughts?
Forgive me, BITOG, for I have sinned. N* owners/mechanics question.
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Buy a bunch of those magic alixirs 
I have hpl ec40 and valvoline premium blue restore on the shelf as elixirs, any other choices? Lol
The name Northstar and easy to access are not synonymous...sorry.
Rocker covers do leak - that's about as easy as it gets, the rest is all downhill from there
Per the Caddy forum, here are the most likely points of leaky leaky:
In order of what's posted throughout this site by frequency -
1. Oil pressure sending switch
2. Oil filter gasket itself
3. Oil filter adapter O-rings/composite seal plate (depending on year) and (if fitted with V03) - oil cooler lines
4. Tossup between cam cover seals and oil level sensor in the lower front of the pan
5. Halfcase and oil pan formed silicone seals (not "gaskets")
6 Rear main bearing seal at the flexplate
7. Front crank snout seal.
8. PCV dirty air line or the earlier type rattle valve grommet.
In order of what's posted throughout this site by frequency -
1. Oil pressure sending switch
2. Oil filter gasket itself
3. Oil filter adapter O-rings/composite seal plate (depending on year) and (if fitted with V03) - oil cooler lines
4. Tossup between cam cover seals and oil level sensor in the lower front of the pan
5. Halfcase and oil pan formed silicone seals (not "gaskets")
6 Rear main bearing seal at the flexplate
7. Front crank snout seal.
8. PCV dirty air line or the earlier type rattle valve grommet.
Lucas stop leak 
YES!! They are tight and leak everywhere and the way the exhaust routes and how the transmission is attached there really is no easy way to fix lower oil leaks w/o pulling the motor....which I did a motor replacement on an 08n Lucerne 4.6 last year. Used LKQ motor and I resealed it before installation. For the record the motor will come out the top, that is how I do these as well as the DTS.
To answer your question on leak points that are common AND you can fix w/o trouble is the oil pressure sensor (it's facing the front of the car) and these make a mess. Also a common thing I see are the trans quick connects in front as well as the one way under in the back that you can get your arm thru the frame opening to get. Other than that - nothing that leaks oil on these can be fixed easy/cheaply the way its all packaged in there.
I would run a bottle of blue devil rear main sealer, snug up any oil pan bolts etc you can reach and degrease it all down and see what happens. If it has a rear main seal leak - I can attest, thru many uses, that Blue devil is the best chance of fixing or slowing it down.
Never put any additives in oil. That only ruins the oil additive package, and viscosity, tbn, and ends up destroying the moving parts and what they touch. A good way to ruin an engine.
If the compression is good on all cylinders, it's time to pull it, redoo all things related to keeping the oil in.
Not what you want to hear, but the truth.
If the compression is good on all cylinders, it's time to pull it, redoo all things related to keeping the oil in.
Not what you want to hear, but the truth.
This stuff actually works on a roof leak, metal @ work.
lol
Driveway sealer? Get the airport grade.