It’s great to know how to fix your own car. You can save big bucks vs. going to the mechanic’s shop and you know the quality of the work being done. That’s not to say the average person has the skills to pull a transmission or anything, but changing your own oil, belts, even doing brake jobs - those things are not beyond the reach of the conscientious car or truck owner.
Those with experience have some things to say about the best times and places to buy the car parts you need.
September, October, and the first half of November are the times of the year when large retailers (Walmart, Amazon) try to get rid of excess inventory. Other auto parts stores will usually do price matching. So the best time to buy motor oil is after Labor Day but before Black Friday.
Coolant is an item most people don’t consume huge quantities of. There’s not really the best time of year to buy it because it’s not a high-volume item.
Speaking of coolant, fixing a radiator is a mid-level-expertise job that a lot of people can do. You can get them anywhere if you price-shop.
These kinds of things are best purchased a year or two at a time.
Amazon.com often runs at least one sale a year on brakes from manufacturers that often have rebate offers at the same time. If you can hit one of those, you’ll compound your savings.
Tire manufacturers like to drive sales around three major holidays – Memorial Day, Thanksgiving, and Presidents’ Day. Sometimes you can take advantage of overlapping rebates or discounts from the manufacturer and the retail location.