Where is the oil sending unit on a 1989 Chevy suburban 5.7 l engine?

On a 1989 Chevy Suburban with a 5.7L engine (likely a TBI, Throttle Body Injection), the oil pressure sending unit is typically located on the driver's side of the engine block, near the oil filter. It's a smaller sensor, often with one or two wires connected to it. It's not directly on the oil filter itself, but in close proximity.

However, to be absolutely certain:

* Consult a repair manual: A Haynes or Chilton manual specific to your year and engine will have diagrams showing the exact location. This is the most reliable method.

* Look carefully: Once you've located the oil filter, examine the surrounding area of the engine block. The sending unit will be a relatively small component with wires attached.

Be aware that some variations might exist depending on minor manufacturing differences. Using a repair manual will eliminate any guesswork.