Search the forum using the power of Google

Viewing 13 posts - 1 through 13 (of 13 total)
  • Can you mix engine oils?
  • ell_tell
    Free Member

    Want to top up my engine oil and looking in the manual a 5W-30 or 10W-40 is recommended. However, I dont know which viscosity is in there at the moment so is it ok to mix oil types?

    Its a Mazda 323f as well is that helps and the previous owners helpful notes suggested a semi synthetic oil should be used.

    Out of interest what do the different designations, 5W-30 etc mean? ūüėÄ

    Free Member

    Yep = you’re probably fine.

    The first digit represents how viscous the oil is when cold ‚Äď the second when hot.

    My understanding is that in a cold country (UK) you’d tend toward the lower of the recomendations and a hot country (Dubai) the higher.

    The main thing is the SAE. More reading here:

    Free Member

    Yes it will be fine but its pretty cheap to change the oil if you have some mechanical know how.

    Its basically temprature ratings and the speed of flow(thickness) markings..

    Full Member

    another yes. All modern engine oils are multigrade, that is, viscous rating for hot and cold.

    Free Member

    Teh numbers are the viscosity (Thickness) ‚Äď the first is when its cold, the second is when its hot.

    so multigrade 10/50 is as thick as a 1o w oil when cold as as thick as a hot 50 weight oil when it is hot

    You can mix oils but its not recomended.

    Free Member

    If you really must mix oils, try to keep to the same Brand and type if possible. (Assuming you know whats in there to start with).
    What year of 323F have you got? I’ve got a T reg 1999 BJ (no sniggering at the back please!)

    Free Member

    Home maintenance is a bit of a small prob for me as on street parking ehich usually means my car is in a different street or boxed in so hard to work on…

    I’m guessing coming into cold winter months something a bit less viscous would be preferable?

    Checked back through the service notes/receipts but cant find any reference to the make of oil used.

    bigyinn ‚Äď likewise a BJ (ahem) here on an 03 plate ūüôā

    Free Member

    It‚Äôll be fine to mix it, regardless of makes and types ‚Äď crack on.

    All oils get mixed during a change, you never get it all out before putting the next lot in ‚Äď if they are not cross-compatible you‚Äôd be stuffed. 99.9% of the additives etc are exactly the same between makes/types, just vary in quantity.

    Free Member

    <pedant mode>
    Viscosity is a measurement of a liquids resistance to flow, not it’s thickness
    </pedant mode>

    Multigrade oils have their viscosity measured at 20degC and 60degC (IIRC! ‚Äď it‚Äôs been a while since I done it), and are matched to the equivalent SAE grade of oil at that temperature.
    For example, a 10W-40 oil, at 20degC is equivalent to a SAE 10 oil, but when heated to 60degC is equivalent to a SAE 40 oil.

    As for mixing oils, for the occasional top-up, it’s not really an issue.

    Full Member

    just get a complete oil change if you haven‚Äôt had this done in the past year or two. Old oils (older than a year or so) tend to degenerate & get dirty. DIY it‚Äôs dirt cheap ‚Äď just remember to take the oil to the tip/recycling centre. Give a local garage or Mr Clutch a call. If it is just a top up then you can mix it without much worry. I guess I‚Äôd wonder where the oil went‚Ķ

    Full Member

    Fine in a car but don’t put car oil in a motorbike (wet clutches slip due to anti friction additives in car oil).

    Free Member

    Yes, OK to mix oil.
    Japanese cars are generally built for worldwide markets so can take pretty much any oil.
    An awful lot of bollox is talked about oils.
    If you are really worried take it to National Tyres and get an oil and filter change for around £25, much easier than doing it yourself and probably cheaper as well.

    Think of all the thousands of second hand cars that get sold every day.
    I’ve never heard of a buyer asking the seller what oil is in it so they can do any future top ups with the same brand.
    And, as coffeeking says, you never get every last drop out at an oil change anyway.
    Oils get mixed all the time and it’s not a problem.

Viewing 13 posts - 1 through 13 (of 13 total)

The topic ‚ÄėCan you mix engine oils?‚Äô is closed to new replies.

Search the forum using the power of Google

Support Independent Mountain Bike Journalism

Like what you are reading?

Bookmark us now and come back again.

Try out Singletrack membership today from only 49p per week

(49p is the weekly equivalent price of the £25 annual digital membership)

Support Independent Mountain Bike Journalism

Singletrack World is a largely reader funded community with over 6,000 members trusting us for their mountain bike news, reviews, adventures, advice and big views.  

Try out Singletrack membership today from only 49p per week

(49p is the weekly equivalent price of the £25 annual digital membership)