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Can you mix engine oil types?

Discussion in 'Motors' started by Frenzy, 9 Oct 2021.

  1. Frenzy

    Soldato

    Joined: 11 Sep 2009

    Posts: 5,409

    Location: Limbo

    Hey guys, so I have 4 litires of 5w40 of one brand and I want to mix it with mobil 1 5w30 xe.

    Are there any negatives to this?

    I'm going for an oil change and I figured if I have the 4 litres laying around I may as well use it.
     
  2. dLockers

    Sgarrista

    Joined: 21 Jan 2010

    Posts: 8,325

    Yes, they're two different types of oils. :confused:
     
  3. Frenzy

    Soldato

    Joined: 11 Sep 2009

    Posts: 5,409

    Location: Limbo

    What are the negatives apart from viscosity changing slightly then? Do you think they chemicals will react?
     
  4. jpaul

    Capodecina

    Joined: 1 Mar 2010

    Posts: 15,555

    I don't think I'd mix synthetic with non-synthetic , but, I don't think you are proposing that, thinking non-synth might break down the synth.
     
  5. Frenzy

    Soldato

    Joined: 11 Sep 2009

    Posts: 5,409

    Location: Limbo

    Nah both are fully synth rated ll04 for my bmw e46
     
  6. andy_mk3

    Capodecina

    Joined: 5 Oct 2009

    Posts: 11,546

    Location: Spalding, Lincs

    Will be absolutely fine that.
     
  7. amigafan2003

    Perma Banned

    Joined: 18 Jan 2008

    Posts: 18,975

    Location: Fylde Coast, Lancashire

    It'll be fine.
     
  8. jsmoke

    Capodecina

    Joined: 17 Jun 2012

    Posts: 10,831

    Oil is overrated.
     
  9. Nasher

    Capodecina

    Joined: 22 Nov 2006

    Posts: 21,830

    There is a video on youtube where someone mixed something like 40 different oils in the same engine and it worked fine :p
     
  10. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,383

    Location: Berks / Moscow

    For how long. An engine would work ‘fine’ for a YouTube video on olive oil too
     
  11. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,383

    Location: Berks / Moscow

    What brand ?
     
  12. bainbridge

    Mobster

    Joined: 9 Dec 2009

    Posts: 4,475

    Location: Bristol

    Modern multigrade oil is a mixture of different oils anyway, so provided you get the correct viscosity it'll be ok, however I wouldn't do it personally because a car engine is usually worth thousands of pounds and for the sake of £40 or so I'd prefer the peace of mind that the correct viscosity is going in.
     
  13. Frenzy

    Soldato

    Joined: 11 Sep 2009

    Posts: 5,409

    Location: Limbo

    Yeah I don't think there would be any harm from mixing them but thinking about it I'll just use it as a top up instead or grab more on the next oil change. Both weights are fine for my car :)
     
  14. Cyber-Mav

    Capodecina

    Joined: 30 Jul 2005

    Posts: 16,326

    Location: Midlands

    Check owners manual, it usually gives you range of viscosity you can use. If it says use 0w-30 up to e.g 15w50 then yea mix and match as long as you dont go outside the viscosity e.g 0w20 or 10w60 etc, well you could use the last two but need to do some balancing calculations. Lol
     
  15. Scania

    Capodecina

    Joined: 25 Nov 2004

    Posts: 24,988

    Location: On the road....

    Two mixed oils are infinitely better than an insufficient quantity of the right oil….
     
  16. dLockers

    Sgarrista

    Joined: 21 Jan 2010

    Posts: 8,325

    You can always throw a pinch of sand in if it's too runny.
     
  17. theone8181

    Soldato

    Joined: 27 Mar 2013

    Posts: 6,342

    That's my thought, I had to top up my m3 once on the motorway and all the garage had was 0w60 (or 5w60 can't remember) . As there were ~8 litres still in the engine I figured it was worth it, the engine was fine ever 20,000 miles later.
     
  18. dLockers

    Sgarrista

    Joined: 21 Jan 2010

    Posts: 8,325

    Didn't you have to get your engine replaced? :confused::o:p
     
  19. theone8181

    Soldato

    Joined: 27 Mar 2013

    Posts: 6,342

    Yea but that was due to a clogged injector staying open, which I don't think was oil based:cry:.
     
  20. turbot1984

    Mobster

    Joined: 6 Jan 2012

    Posts: 2,824

    Not an M3 i hope?