synthetic or regular oil, oil change after how many miles?

5k for dino, if you switch to syn, 10k after that.

 

Make sure you're checking your oil between changes, with that many miles there's a decent chance that you're using at least a bit.

 

you change oil once a year regardless of oil type or (low) miles driven.

 

*Should* is very subjective and dependent upon environment (what type of driving you're doing). Here's my oil-change routine, which may or may not vary from factory recommendations (which may or may not be correct in the first place). I drive mostly city miles in a fairly dusty area.

1) 5k miles or six months, regardless of whether its dino or synthetic. Synthetic CAN go longer, but I like doing the work and don't mind spending a little extra to keep my oil fresh. I trust synthetic oil to go 10k or more, but I don't know if I trust the filters to last that long, and if you end up with a clogged filter, it doesn't matter what oil you use, you're going to wish you'd changed the filter sooner. Better safe than sorry, imo.

2) I always use synthetic, but I have also never had a problem with dino. The key is proper intervals. Change your oil when it should be changed, and your engine will be fine. Other elements of your car will break down long before your engine if you follow proper oil change intervals (Of course, this is following the law of averages. There's always a chance of a bad apple here or there, and if you've got my luck, you'll find that bad apple.)

And as another poster mentioned, check your levels periodically between changes to see if you're burning any. My current Prius with 145k doesn't burn any, but my old Echo with 220k went through a qt every 2k miles.

 

1.Change the oil and filter at least as frequently as specified in the maintenance schedule. Regardless of the longer intervals Toyota's touting in the 'States, some cautious owners prefer 6 months or 5000 miles, whichever comes first. I'm in that camp. Actually in Canada, the normal interval is 8000 kilometers (roughly 5000 miles) or 6 months.

2. Use at least the specified oil grade. I don't think Toyota makes any mention, synthetic vs regular. I believe 0W-20 (for example) will be synthetic by default. If you're using something like 5W-30 and a quality regular oil is available cheaper, I'd use that.