Synthetic/Semi Vs Conventional Car Oil?

Goremans on 21/01/2025 - 11:18
Last edited 21/01/2025 - 13:39 by 1 other user

Hey all, I've read so much contradicting information on this topic - I'm turning to OzB to help me.

I have a 2006 Hyundai Elantra with 150K (for how old it is it's in pretty good shape). We've kept up with its maintenance.

I'm looking to start changing the oil myself, as, long story - I have more time and less money.

As I understand as a car ages then a thicker oil (non fully synthetic) is preferred?

Thanks in advance

**edit my manual calls for this: sae 5w-20 ilsac gf-3

Which would this expensive stuff: https://www.ebay.com.au/itm/163375910880?chn=ps&_ul=AU&_trkp…

• 

  shxhshzhz on 21/01/2025 - 11:33

  +3

  Thicker means the XW-XX specification, not the type of oil. Larger numbers mean thicker oil, e.g. 15W-40 is thicker than 10W-30. Use the oil recommended in your manual.

  • 

    Goremans on 21/01/2025 - 13:12

    +1

    How did I not know that! Ok, no worries, ill check over the manual again. I guess regular changes are most important

  • 

    Goremans on 21/01/2025 - 13:40

    My manual calls for this sae 5w-20 ilsac gf-3

    Which would this expensive stuff: https://www.ebay.com.au/itm/163375910880?chn=ps&_ul=AU&_trkp…

    • 

      shxhshzhz on 21/01/2025 - 14:15

      +1

      Are there any other options? Common cars don't usually use these uncommon oils. Supercheap Auto's website says 5W-30 is compatible. Is that written anywhere?

    • 

      MS Paint on 21/01/2025 - 14:23

      +2

      I can guarantee that your mechanic or dealership is just filling your car with 5w30.

      • 

        Goremans on 21/01/2025 - 14:32

        I think he does use 5-30 - is there any benifit using thinner (5-20)?

        What does the ilsac gf-3 mean?

    • 

      brad1-8tsi on 21/01/2025 - 16:07

      +1

      My manual calls for this sae 5w-20 ilsac gf-3

      That would be for cold weather (snow) use in North America. I'm guessing you are reading the table incorrectly.

      You are best to use one of the "oil finders" on the oil companies web site.

      Nulon & Penrite both say use 10w-40 full synthetic which makes more sense than 5w-20.

      Hopefully you have the correct tools, jack stands, drain pans and somebody to guide you through the process.

• 

  pscac001 on 21/01/2025 - 11:34

  +4

  Check if the invoice from past services tells you what sort of oil it has in it. If you aren't noticing any problems, keep using that. If the engine is leaking or noisy, then moving up to a thicker oil might help a little bit. Don't change from mineral to synthetic or vice versa.

  • 

    Goremans on 21/01/2025 - 13:10

    It has been slightly noisier - but that could all be in my head. Ok will do, weve got a great local mechanic. - we buy him christmas chocolates every year.

• 

  jv on 21/01/2025 - 12:11

  +2

  As I understand as a car ages then a thicker oil (non fully synthetic) is preferred?

  Not really, it depends…

• 

  wannagrababargain on 21/01/2025 - 12:56

  +1

  Plug your car details into Supercheap auto website or the iPad in store and it will tell you what oil to buy. Pretty much all modern engines are designed for a fairly thin synthetic oil and that never changes throughout the engine life.

  PS Change the oil filter too.

  • 

    MS Paint on 21/01/2025 - 13:10

    +2

    iPad in store

    My local had replaced this with a QR code to scan.

• 

  Goremans on 21/01/2025 - 13:08

  Absolutely, will be changing filter also. Cheers

• 

  Russell Dupsumtucka on 21/01/2025 - 13:28

  If the engine is still in good condition (no smoke or rattles) then use the same viscosity as it has from new (probably 5w30).

  Thicker oil could cause more issues than you believe it will fix.

• 

  JimB on 21/01/2025 - 14:43

  +1

  "my manual calls for this: sae 5w-20 ilsac gf-3"

  It also depends what climate you live, the same engine in a hot climate may have a different recommended viscosity to one of a colder climate. colder the climate, thinner the recommended oil.

  5w20 isn't so common for a non-performance 20yo car.

  I'd bet 5w30 (slightly thicker when oil is hot) would be suitable for your car (if 5w20 was one of the recommended specs).

  Semi-Synthetic will be fine, however if you're saving money by DIY, use the savings and spend an extra $10 or $20 on Synthetic.