Before you start work on Highlander engines, take these steps: disconnect the negative battery cable and drain the engine's coolant. Cover your engine by taking off the air intake duct that lies above the radiator, then removing the splash shields that cover the engine's underside around the radiator and any engine covers that may be there. Before working on 2008 and newer models, take off all three parts mentioned - radiator grille, hood latch cover, and hood latch - and disconnect the electrical connector going to the Hood Courtesy Switch if applicable. Separate the radiator support cover and the radiator support assembly first if they are equipped. After that, take off the hoses for both the upper and lower radiator connections and the coolant reservoir line from around the radiator opening. 2008 and every model year after, pull out the battery first. On all 2008 models onwards, take off the engine oil cooler tubes before proceeding. Place a tray under the radiator and use caps to stop fluid from running while you disconnect the cooler lines from the transaxle. On 2008 and newer cars, loosen the condenser holding bolts and pull the condenser partway off before moving it away from the radiator. Untwist and remove all electrical fan connections. Also, disconnect any wires or brackets connected to the fan shroud and radiator. Remove the radiator mounting hardware and pull out the radiator and fan cover together, and later unfasten the fan unit from the radiator parts. Look the radiator for leaks, damage, clog, then clean it by blowing air and brushing it with a soft brush, being sure not to bend the cooling fins and using eye protection. Put everything back together while making sure the rubber seals fit properly, and refill your cooling system correctly mixing antifreeze and water. Fire up the car and let it warm up normally, then look at your coolant again and pour more if needed. Take a look at both the automatic transaxle fluid and top it off, if necessary. The coolant reservoir attachment method varies by Lexus and Highlander model year. Most versions pull out of a bracket on the fender well, but those for 2004 and later Lexus models and 2007 and later Highlanders mount directly to the engine cooling fan shroud and cannot be unscrewed. Tilt the car to drain the coolant into a bucket, wash and check the reservoir for spot damages, and place a clean one back when you're done.