Hello everyone,
I own a 2006 Hyundai Sonata 3.3L V6 sedan. The car currently has 81,000 miles on it and around 80,000 miles I put full synthetic Castrol Magnatec 5w-20 oil into it. From when I bought it at 60,000 miles to 80,000 miles I was only putting convential Castrol oil into it and the engine would not burn a smidge of oil between changes. Now around 81,000 miles, just 1,000 miles from my synthetic oil change, I’ve burned a little more than a quart of oil. If I switch back to conventional will the burning oil problem stop or is there now permanent damage done that needs to be checked by a mechanic?
What weight of oil did your owner’s manual call for? If it was 5W30 non synthetic and you are now using 5W20 synthetic I can understand. Synthetic is an incredibly good lubricant and very slippery. Older cars often experience oil consumption with thin synthetics due to larger clearances.
Try a 5W30 synthetic and see if it makes any difference.
The manual calls for either 5w20 or 5w30. I figured it would be fine to switch to fully synthetic because it didn’t say I had to use conventional/couldn’t use synthetic, just either 5w20 or 5w30. I drained out the full synthetic oil earlier today and filled it up with some Pennzoil high milage conventional oil. I hope that the engine will continue to never burn oil as it did before.
One theory, the synthetic oil is much better at cleaning gunk and deposits from the oil system. It may be that it cleaned it so well that an oil leak has developed. A leak that was plugged up by gunk before. Suggest to have your shop check for external oil leaks. You could park your car over a big piece of cardboard at night and the next AM check for oil dripping too.
I have experienced that twice on higher mileage engines. I only use synthetic oil and changing over with a used car after 80-100K miles using regular oil sometimes causes oil usage beyond what the engine has seen in the past. @George_San_Jose1 is right, synthetic tends to clean the inside of the engine better than regular oil. It might be a leak, it might just be cleaning the deposits off the rings.
Short-change the oil at about 3000 miles and continue using synthetic and I’d bet the oil consumption improves by quite a bit. If it doesn’t switch back to regular oil and the consumption should go back to normal.