I have a 2014 Prius V with
I have a 2014 Prius V with 175,000m miles. As second owner I purchased dealer maintained with records at 137,000 miles. It does/has not used any oil between 5000 mile oil changes. Has not (never) used any coolant since I changed all fluids a year ago. Occasionally I have an unpredictable rough cold start in the morning. Randomly occurs once every 4-6 or so months and lasts 15-20 seconds. Freaks me out! Then runs uneventfully smooth for months at 44+ mpg. I primarily use Sunoco or Shell - sometimes Mobil. I frequently alternate octane choices between 87 and 89.
Would it be prudent to replace the EGR cooler for pre-emptive head gasket preservation? I recently discovered what that occasional cold start knocking was all about. Now I'm ready to over react! Is it worth changing the EGR valve as well? Of course I will clean intake manifold as well. Is it too late to put the occasional devil back in his bottle? Thank you for providing insightful info! BobW