I have a 99 Dodge Caravan 2.4L 55k miles, and I never replaced the original spark plugs (I know, the manual says every 30k but the engine runs smooth so I just forgot about it). At 10 years, do you think I should get the plugs changed, or is it likely that they've seized to the head already, and I should just leave it alone? I'd like to keep the car another 10 years but I don't think the plugs will last to
100k. Same question on an '02 Toyota Corolla with 60k miles, manual says replace plugs at 120k/8years, but would they have seized by 8 years? Should I just ask my local mechanic to loosen and tighten each plug (not replace) annually to avoid seizing?(Another question, the Caravan has original timing belt, manual says replace timing belt at 120k miles, 8 years. 2.4L is a non- interference engine. Should I replace the timing belt now or wait another year or two?)
Thanks (planning to do better maintenance in the future...)