Here's why:
* Reduced Mess: Some oil will inevitably spill when you remove the water pump, especially if it's located near the oil pan. Partially draining the oil minimizes the mess and the amount of oil you'll have to clean up.
* Easier Access: Lowering the oil level provides better access to the water pump and its surrounding components. This makes the job easier and less prone to damage.
* Prevention of Oil Contamination: While unlikely, there's a small chance of coolant mixing with the oil if the oil level is high. Lowering the oil minimizes this risk.
Instead of a full drain, consider:
* Siphoning: Use a siphon pump to remove a few quarts of oil from the oil pan. This is a less messy alternative to fully draining the oil.
* Partial Drain: Remove some oil through the drain plug, but don't completely empty the pan.
When a full drain might be necessary:
* Some specific engine designs: In rare cases, the water pump might be positioned in a way that makes complete oil removal necessary for access. Consult a repair manual specific to your vehicle.
In short, while not strictly mandatory, partially draining the engine oil is a prudent and highly recommended step before removing a water pump to make the job cleaner and easier. Always consult a repair manual specific to your vehicle for the best instructions.
