The oil pump on your Oldsmobile Silhouette is located inside the oil pan, which you need to remove to gain access. However, this may be an involved task and require the use of special tools, depending on your particular Silhouette model. If you need these special tools, check first at an auto parts store or tool rental shop in your area before you start this job.
On your 3.1L model, raise the front of the vehicle, remove the crankshaft damper or pulley and drain the engine oil. The rear of the engine is equipped with flywheel shields that you need to remove as well. Since you will need to make as much room as possible and raise the engine to detach the oil pan, remove the starter motor and support the engine at the transaxle mounting bracket.
With the engine properly supported, unfasten the engine mount bracket bolts at the engine and raise the engine just enough to access the oil pan mounting bolts on that side. Then you can remove the oil pan mounting bolts, detach the pan and gasket.
With the oil pan out of the way, you will have access to the oil pump. Remove the pump and drive shaft extension. If you decide to remove the pickup tube for inspection and cleaning, make sure you have the appropriate gasket for reinstallation.
Before reinstallation, clean the gasket mating surfaces on the oil pan and bottom of the engine and use a new oil pan gasket.
Removing the oil pan to gain access to the pump on these models requires the use of special tools to help you hold the engine in place since you will need to loosen the engine mounts. Install a universal engine support fixture and adapters on top of the engine compartment to help you hold the engine in place.
Now, raise the front of your Oldsmobile, drain the engine oil and remove the oil filter drip shield, bolts and shield. Also, detach the exhaust pipe from the manifold and place jack stands under the front and rear of the frame. With the frame secured, unfasten the engine mount nuts at the frame and the transaxle mount nuts at the frame.
Now, you will need to lower the front of the frame. For this, loosen the rear frame bolts and remove the front bolts. To gain access to the oil pan mounting bolts, remove the engine mount and bracket, the starter motor, the oil level wiring harness connector and the transaxle bracket.
After removing the oil pan and gasket, unfasten the single oil pump mounting bolt and remove the pump and drive shaft extension.
To gain access to the oil pump gears, remove the engine front cover. Then detach the oil filter adapter, pressure regulator valve and spring. The pump has a cover that you can remove by removing the mounting bolts. Under the cover you will see the pump gears, which you can remove now.
The oil pump body is located under the oil pan. But before raising the front of your Silhouette model, remove the crankshaft balancer with a suitable tool. Then, jack up your vehicle to gain access to the oil pan. First drain the engine oil and then unfasten the pan mounting bolts. Once you remove the pan, remove the gasket and oil pump.
