2010 Toyota Highlander hybrid 240,000 miles automatic. (New hybrid battery installed at 160) Car runs great, I took it across the country and back with no issues last month, I do have a micro crack in the radiator but it's so small I only add less than a teaspoon every month. The problem I have is that I live in Colorado and when I drive uphill (especially if trying to go fast) my hybrid battery empties and when it's all done and all the power is coming from the engine it starts to overheat. This happens almost nowhere else on my driving (which I do a lot of) and only happens if the grade of incline is high and I drive uphill for an extended period. Also it never occurred during the winter. Got any ideas?
Your cracked radiator may also be partly clogged, thermostat not opening enough, water pump impeller corroded, fans not working, etc. it's a 12-year-old vehicle with hundreds of thousands of miles on it, could be any of a number of cooling system problems. The engine has to work harder going uphill without the battery assist.
Check the site FAQ for tips on diagnosis.
Radiators need to hold pressure. Replace it
The small micro crack in your radiator will not stay small and one day when it develops into a macro crack and your car really overheats and possibly damages the engine you will wish that you had replaced it while it was still in the micro stage.
Have you ever had a small tear in your jeans? Did it stay small? As my grandmother used to say, "A stitch in time saves nine." 🙂
And perhaps the current overheating is due to one or more of the suggestions that @ChuckTobias provided, and those need to be addressed as well, but as @MountainManJoe advised regarding the cracked radiator, "replace it." 😉
