If you mix different manufacturers' oils but same spec eg 15/40 is that a problem? Also if you mix different specs eg 20/50 and 15/40 is that a problem? (If so, why?)
It's actually a very good question. I have topped up with the wrong oil once or twice on the theory that some oil is better than not enough, but what is the right thing to do? I imagine it's not a major issue with mineral oils but that's only me guessing...
It will change the spec of the oil, but I've been doing it all my working life and never had an issue. You must never mix synthetic and mineral oils If unsure what's in there use semi synthetic as it's compatible with both.
20/50 etc. is not the spec., its a grade of oil. Check the API/SAE spec and use that as your guide. Tony
You can mix oils from different manufacturers and mix different grades and types without any problem but I’d use synthetic in your Scooby engine and avoid mixing mineral with it.
Do you mean you topped up with SAE 30? It’s best not to mix oil types and grades so you know what’s in the engine but it’s not a major issue, you’ll just lose the advantages of synthetic if you mix mineral with it. But it might reduce an oil leak
That’s not correct; they are chemically different but they are compatible and will mix. A semi-synthetic is a blend of mineral and synthetic and most oils sold as mineral contain some synthetic. However, the additives in different types of oil may interact and there may be a reduction in the properties of the additives.
No it was probably 20 yrs ago ! And if my mechanic friend tells me he's usually spot on Sent from my iPhone using Tapatalk
