2013 Chevrolet Silverado 1500 — coolant is old by age but mileage is low

If it were in my driveway, swap the cheap/easy piece first on the 2013 Chevrolet Silverado 1500 and see if the fault moves. Save the big job until that test fails. Run the total, not the monthly, before you commit. Not interested in a five-hour wait for a shrug.

Ask what changed right before it started. Write temp, speed, and in-gear vs coast when the 2013 Chevrolet Silverado 1500 does it — then decide on parts. That's the branch I'd chase this week. Do that first. Wrote this up on my lunch break.

Log the conditions before you spend. Two 2013 Chevrolet Silverado 1500s can feel identical and have different causes, so measure before you copy someone else's repair. If the cheap test changes it, stop and reassess. On “coolant is old by age but mileage,” that was the fork that mattered for me. Do that first. Cold start is when I can actually reproduce it.