Do I need to drain the cooling system to install this?

Yes. Drain your coolant into a clean container before removing the old tank. You can reuse it if it's clean and hasn't been sitting exposed. Once the new tank is bolted in, refill with fresh coolant to the proper level.

Will this tank work with my current coolant, or do I need to flush the system?

Use whatever coolant your Highlander requires—the tank itself doesn't dictate that. If your system hasn't been serviced in years, a flush is smart practice anyway, but not strictly necessary for the tank swap.

What if the tank comes cracked or leaks after I install it?

Contact ModSupply with photos and your order number. We handle defects—don't drive on a leaking coolant system.