* One is near the front of the engine block.
* The other is near the rear of the engine block.
Because there can be slight variations depending on the exact engine casting, using a repair manual specific to your vehicle's year and engine code (found on a sticker under the hood) is highly recommended to pinpoint their exact locations. Trying to locate them without a proper diagram might lead to wasted time and potential damage. A visual inspection with the proper diagram will be far more efficient.