How do you replace valve seals on a Toyota Avalon?

To replace valve seals on a Toyota Avalon, first, remove the valve covers and the necessary components to access the cylinder heads, such as the intake manifold and spark plugs. Use a valve spring compressor to remove the valve springs and retainers, then gently pull out the old valve seals and replace them with new ones. Reassemble the components in reverse order, ensuring all parts are torqued to the manufacturer's specifications. Finally, check for leaks and ensure everything is functioning properly before starting the engine.