Oil filter location on 1998 catera - 1998 Cadillac Catera

found this link.
https://www.justanswer.com/cadillac/21gaw-transmission-dipstick-a1998-cadillac-catera.html

HI. This will normally be the result of a failed oil pan gasket. With that said, I will list other areas of concern below. Have theses areas checked for faults asap.

1. Loose or improperly secured oil outlet screw.
2. Failed oil plug screw ring gasket.
3. Failed head gasket
4. Damaged or overly secured oil filter device.
5. Damaged or deteriorating oil pan gasket.
6. Damaged or breached oil pan.

OIL PRESSURE SENDING UNIT LOCATED ON THE OIL FILTER ADAPTER ABOVE THE OIL FILTER.

Hi, it is located on the driver side of the car, in the engine block, Lift the car and safely support the vehicle. Slide under the car behind the driver side wheel. You can see it with 1 mounting bolt, its located near the base of the engine block next to the oil filter. It is very difficult to remove because the wire runs so tightly between the exhaust pipe.
Take care

It is very small (fist size) and should be located on the opposite side of the engine were the starter is

If you are asking where is the oil pump it is inside the oil pan under the engine

The oil separator is otherwise known as the oil filter.

I don't have a diagram, but your problem is the oil cooler underneath the intake on top of the engine. Remove the intake, and the cooler is right there in between the heads. Easy to change once you get the intake off. This is a VERY common problem on Cateras, and the symptom of it is oil in your coolant. I have a 1998 Catera and had the same issue.

It's a crankshaft position sensor. the sensor itself is located right under your oil filter ans the wiring runs back up behind the top of the motor.

the noil filter is in a canister under the exhaust manifold drivers side, a 1/4 inch ratchet should help getting it off, can relace with spin on filter from FRAM