Do I need to drain the entire cooling system before installation?

Yes. Disconnect the lower radiator hose first to drain fluid, then unbolt the radiator from the mounting tabs. Refill with fresh coolant after the new unit is secured and all hoses are reconnected and bled for air.

Will this fit if I've modified my engine bay or fan setup?

This radiator is designed for stock RX300 configuration. If you've swapped fans, brackets, or core support, test-fit before committing—the mounting points are factory-specific.

What hardware do I need to install this?

You'll need basic hand tools and new coolant. The radiator uses the factory bolt holes in your core support. Check your service manual for torque specs and coolant capacity—don't reuse old hoses if they show wear.