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5w30 vs 5w40 engine oil

  • 25-07-2023 7:40am
    #1
    Roberto_gas
    Registered Users, Registered Users 2 Posts: 4,508 ✭✭✭


    I have 5w40 oil sitting which i want to use on my car which is recommended 5w30…is it ok to use 40 or it will cause issues? Also can u mix 30 and 40?


    Thanks in advance



Comments

  • #2
    BlakeS94
    Registered Users, Registered Users 2 Posts: 1,331 ✭✭✭BlakeS94


    The only difference between the two is viscosity at engine operating temp.

    The 5w40 will be thicker and won't flow as well as 5w30.

    Mixing them for a top up would not cause an issue provided the oil is within manufacturer spec, that's the most important part.

    But personally I wouldn't go doing a full oil change with a different viscosity oil.



  • #3
    newmember2
    Registered Users, Registered Users 2 Posts: 2,586 ✭✭✭newmember2


    https://www.boards.ie/discussion/2058306333/5w30-vs-5w40-engine-oil

    I think you can mix yes but it will give you a different weight oil.



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