In the oil pan It's in the timing cover. The culprit is most likely the pickup screen in the oil pan. Take it off and clean it.
check the oil pressure snding unit first then check the pressure gage if both are good you need to replace oil pump Oil pumps in buick 3800,s do not go bad. Replace sending unit or the oil pump pickup screen is clogged.
A 1992 Buick Regal 3800 needs approximately 4.5 quarts of oil. The oil can be purchased at any auto parts store such as NAPA.
If it doesn't have an oil pump, the engine will seize right after you start it. If this has a 3800 engine (I think it does) the oil pump is mounted to the inside of the front timing cover. The crankshaft passes through the oil pump directly driving the pump, so there's nothing that can break to prevent operation of the oil pump.
4.3 liters
4.5 qts
Fig. 19 Oil Pump Assembly
the 3800 oil sending unit should be on the side of the block. It is screwed in right beside of the oil filter.
The 3800 engine take approx. 4 1/2 quarts of oil with filter replacement. TechJK --------------------------------------------------
in the oil
Neglect to replace the supercharger oil.
I have the same problem with the same vehicle, the oil pump is on the inside of the timing cover. good luck
You can prime the oil pump on an 85 Buick Regal by removing the distributor and inserting a priming rod onto the oil pump shaft. It can then be turned by hand or with a drill to distribute oil throughout the engine.