Q: Can 2006 Toyota Sienna radiator with plastic ends be replaced with an all meta version

There are no material or system incompatibilities at all due to the metal versus plastic. The anti-freeze itself has corrosion inhibitors to protect the radiator and all metal cooling system components. The best fit and function is always obtained using the Toyota OEM radiator, however, the Toyota part is often (not always, but "often") more expensive. If you are replacing the radiator due to an episode of overheating, be sure to install a new engine cooling thermostat. An engine cooling thermostat is subject to damage from overheating and failure of that component could create new engine cooling problems. If you desire that a certified mechanic install your new radiator, please use YourMechanic’s radiator replacement service page to request service. When you review the quote, if you desire you can select, "I am using my own parts" unless you want yourMechanic to procure the radiator for you and include it in the price. The responding mechanic can handle the thermostat replacement as well. If you have further questions or concerns, do not hesitate to re-contact YourMechanic because we want you to make the most of your repair dollars and help you to get the best possible results.