5W-30 is good for older engines, especially as a step up from the thinner engine oils like 5W-20 that is used in the early 2000s.
Although it also depends entirely on your vehicle's original manufacturer specifications and the overall engine wear.
5W-30 engine oil is good for older engines, but it's not the correct oil for all older engines.
You should always follow the vehicle's owner's manual or use the correct oil that is listed on your engines oil cap if it shows it.
If your vehicle calls for 5W-30, you should stick with 5W-30 oil.
If your engine specifies 5W-20, it's often recommended to switch to 5W-30 engine oil for older and high mileage engines that are over 100,000 miles to provide a slightly thicker and protective layer under heat and load.
And for older classic cars and engines from the years of the 1970s, 1980s or even 1990s that originally used and specified thicker oils like 10W-30 or 20W-50 engine oils, then 5W-30 engine oil may be too thin and could result in low oil pressure, noisy lifters or burning oil.
If you're using 5W-30 engine oil in a high mileage engine, you should buy a high mileage 5W-30 engine oil as they contain specialized seal conditioners to prevent leaks and additives to reduce oil consumption.
The 5W rating on the engine oil also ensures that the engine oil flows quickly during cold startups in the winter, and the 30 rating provides good protection at higher engine temperatures.
And if you live in an extremely hot climate, then using a slightly thicker engine oil like 5W-40 is also sometimes preferred.