I have just bought my first car in about 30 years... 2nd hand. It's about due for an oil change. I need a refresher course on motor oil from you gentlemen. First is the weight of oil. I live in Hawaii for starters. Engine recommendation in the manual is 5w30... What I can remember is that one used the higher weights for hot climates and the lower weights for typical wintry conditions with low ambient temps.

The temperature here seems to never drop below 60 Fahrenheit (say 17c) where I am located. That's early morning temp in January. So is 5w30 the correct weight oil to use?

Secondly, the synthetic vs conventional oil debate. I am reading online that synthetic actually lasts longer so I would like to go with synthetic. I have no idea what oil is in the engine at the moment. I have seen folks state that one cannot switch between conventional oil and synthetic. Other folks state that there is no problem in doing so. So what's the opinion of folks here? thanks

  • Your owners manual should give you a chart for specific climates. Jan 14, 2017 at 4:51
  • There should not be a problem switching between types of oils at all
    – method
    Jan 14, 2017 at 4:54
  • manual just says 5w30...
    – thurgood
    Jan 14, 2017 at 5:03

1 Answer 1


If the owners manual (and probably on top of the oil filler cap) states to use 5W-30, that's what you should use. Today's engines are engineered to use a specific weight of oil. The tolerances inside the engine are setup to the specific weight. To use something else can cause premature failure (over time) and/or worsen gas mileage.

You should have absolutely no fear of synthetic oil. Most of what you read on the internet today is about wives tales from yesteryear. The thought used to be that switching from dino oil to synthetic would cause leaks to occur. The only way synthetic can cause leaks to occur is if the higher cleaning synthetic were to clean out dino oil deposits within the engine on seals or gaskets. This might open small areas where leaks can occur. This is such a longshot of happening, it pretty much isn't worth worrying about. Synthetic oil will provide great lubrication for your vehicle.

While synthetic may be able to run longer in your vehicle, if the vehicle is still under warranty, you'll still need to maintain the proper oil change interval in accordance with the manufacturer's maintenance schedule to keep the warranty intact.

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