Lexus GX460 coolant leak issue with overheating and low coolant levels on Lexus GX460

Some Lexus GX460 owners report experiencing coolant leak issues that may lead to overheating and low coolant levels. These leaks can develop from the valley of the 4.6 liter 1UR-FE engine as it ages, causing coolant to pool and potentially run down the back of the engine or the transmission. Many owners note that the coolant valley plate leak tends to arise as the vehicle approaches around 100,000 miles, and repairing this leak can be costly. It is recommended that owners monitor the overflow tank for low coolant levels as an early sign of a coolant leak. However, it is worth mentioning that by 2016, some of these coolant leak issues, including the valley plate leak, appear to have been addressed by Toyota.