2001 LS430, 160k
Replaced the timing belt at 80k. Annual summer trip to Vegas from LA. Engine temperature normal all those trips. Just this past weekend, with the A/C running, outside temperature about 107 F, the engine temperature got a full notch higher while climbing the grade. It got back to normal the minute it reached the top of the grade. It's time to replace the timing belt/coolant once again. That red stuff is well worth the money! and for me last a good 5 years, 80k.