It’s true. I’ve fallen way behind on maintenance for my 2007 Toyota Highlander. Now, I’m trying to figure if I need to do anything different to help “catch up” and save any vehicle components.
The service guide recommends that I “replace engine coolant” at 100k miles, but I never did. I’m now at almost 180k. Does Toyota mean a drain & refill, or a flush? Since I’m overdue, is there something else I should do to the coolant system? (The engine temperature has been steady since the day I bought it used, so I assume I don’t have major cooling issues.)
The guide also recommends replacing the spark plugs at 120k. I’ve read multiple websites that list symptoms of needing new spark plugs (starting problems, rough idling, etc.), but I have none of those symptoms. Should I wait for a symptom, or pre-emptively replace the plugs?
The guide does not mention replacing transmission fluid. They just recommend inspecting it. Should I replace it? (I have noticed that changing gears is not as smooth as it used to be.)
(For what it’s worth, I’ve gotten the other items done - replaced air filters, changed engine oil and filter every 5k miles.)
I’d appreciate any advice. Thanks!