75k miles, automatic,
11 sonata limited 2.4 non turbo,
I use my car all day for work delivering. My manual says 3.7k miles intervals, my mechanic says 3k. But Scotty says highway miles are a 1/10th of city miles. I’d say my miles are 60%hwghy,40% city’. I’m at about 3.2k miles from my last oil change. I plan on testing the oil this time. But idk if it really necessary as my gdi engine is burning oil I believe. I had to add some oil in at about 3k but maybe I should just change it then, but Does this affect how often I should change it?
Burning oil does not change how often it should be changed. When you add 1 quart of clean oil to 4 or 5 quarts of dirty oil you wind up with - an engine full of dirty oil.
Those cars are known for oil burning and other engine problems, but a quart every 3000 miles is not all that bad. Changing the PCV valve may help. If you want the engine to last as long as possible change the oil and filter on time. The general rule of thumb for modern engines and synthetic oil is 5000 miles, but if your owner's manual says to change it more frequently stick to that.
3.7 or 3 is an insignificant difference. Yes, highway driving means you can stretch out the interval a bit, but Hyundais being what they are, I wouldn't extend it too much. Normally we recommend 5-7k intervals, so you're already on the overcautious side. I'm surprised the manual says 3.7k miles. It's unusual but I'd say stick to that.
Let us know your analysis results.
