Mixing oil…….

[NYSail]

So doing my annual oil change. Unfortunately I put oil into a clear container (leftover from last year) and didn’t mark it. Could be 15 / 40 (engine) or 30 wt (trans). Little less than a quart. Was thinking I would rather make the mixing (if I do) in the engine rather than trans. Obviously it will change the real viscosity But are there any issues in doing so. Engine takes about 5.5 quarts total.

thanks
Greg

 

[Don S/V ILLusion]

Don’t know if there is any empirical data indicating any difference in lubricity, engine performance or engine life resulting from mixing viscosities so this is largely an academic opinion question. Personally, if it’s 1 qt out of 5+, I would just dispose of the unknown quart and not concern myself with the effect if any.

 

[Ralph Johnstone]

Little less than a quart.

Ditch it.

 

[Calif. Ted]

I've done it using the same brand of oil, I wouldn't mix brands, in engines, not the trans. The mixing of additives from different brands can be problematic I believe. Here's a link to a viscosity calculator if interested.
Mixing Viscosity (Blending) Calculator - ÖleZol

 

[Tally Ho]

I am as cheap as they come and I would pitch it and buy new so you know. Use the unknown oil for bar oil on your chain saw or burn it for a fire starter.

Greg