How often to change synthetic motor oil and/or oil filter
Same as regular.
As usual, Texases is spot-on.
Despite any promotional material you may have seen to the contrary (of oil change frequency, not of Texases).
I don’t know, because you did not tell us what make model or year car or truck or maybe boat or railroad engine.
You have the answer in the owner’s manual. You don’t change the oil change schedule due to changing to synthetic. While you may be able to stretch it out longer, I don’t recommend it.
Under warranty whatever the manual states. Out of it whatever you feel comfortable with. A whole forum on it is www.bobistheoilguy.com
Two categories of driving conditions, normal and severe. Severe takes a shorter OCI that the normal. If your vehicle is bigger than 14 quarts, it might be a good idea to do an oil analysis to see if the oil needs changing. I had one done with only 5 litres which sounds like I wasted my money but was curious so I was happy with the feedback which said it was OK and didn’t need changing.
Change it at the intervals recommended in the owner’s manual.
If you’re in warranty, change it as often as the owner’s manual requires. If you’re out of warranty, you might be able to stretch the interval a bit, but why risk it?
Honda Civic (see tags below OP). But still no year. I’m still getting used to the tags, too.
JazznArt, why do you want to use synthetic in a Civic? It runs perfectly well on petroleum products; synthetic is not at all needed.
If the car is still under warranty, change oil and filter at the intervals recommended in your owner’s manual to protect the warranty. I use the dealer for oil changes, even though they are more expensive than an independent shop, so that they have no one else to blame if a problem occurs.
Typically, there are two schedules for oil changes. One is for “normal” service and the other, usually twice as often, is for “severe” service. “Normal” service isn’t normal at all; it means almost exclusively highway driving which is very easy on the oil. Everything else, which is how most people use their cars, is “severe” service. Once your warranty expires, you can safely narrow the definition of “severe” to mean mostly short trips in stop and go traffic.
Thirty years ago, I worked for a transportation company that had its own oil lab. Since I knew the technicians, they would slip in personal samples now and then. At the time, I had a small, 4 cylinder coupe that I used for everything from commuting to work to club racing on road courses. I stopped worrying about oil change intervals after they showed me that my oil was still in good shape after 6,000 miles. Today’s engines run cleaner than they did back then and oils are better. Therefore, it should be safe to go longer between changes.
You need to tell us what year civic. For Civic’s this is important. The newer models specify a 5w20 oil and the Honda version of this oil is synthetic. If that is what your Civic calls for, then use the 5w20 synthetic and follow the owners manual.
If this is an older Civic that calls for 5w30 (see top of oil cap on engine), then you can use conventional or synthetic. If the maximum interval is 7500 miles, then you can use that for synthetic even if your driving calls for the severe schedule with more frequent changes.
Change the filter every time you change the oil.