crw

I meant to order Brad Penn 20/50. I accidentally ordered 10/30 on Amazon

Should I order more, mix 1/2 and 1/2 and make it 15w40.

Or, can I get away with using the 10/30?

NYC993

no way!
i would not use 10-30 or mix it on aircooled.

ilko

15-40 is a good oil for climates that see cold temps. But the question is whether the 10-30 oil has enough of the ingredients that make 15-40 and 20-50 good for our cars.

NYC993

Xw30 are for US and japanese cars if im not mistaken.

let's not forget that oil temps on air/oil cooled cars get higher by the engine combustion components then in watercooled cars. Oil is used to cool the engine. You want oil that won't thin out and shear in the higher heat, hence w50 and w60 oils for aircooled. And yea anti-wear stuff also needs to be there in right quantty.

These are expensive engines to experiment with.

rlme36

Return the oil and avoid the horror of an oil thread war on viscosity

Vandit

You might end up with an oil pressure warning light at idle. Return it and get the right stuff.

pp000830

Not to worry, if its API label shows it to be acceptable for one of your other cars you can use it there.

Railmaster.

Oooooilthread!

mhm993

Find a buddy with a spec miata who uses 10/30.

crw

I can dump it in the C6 corvette - those things are robust.

sacman

it's cheaper to give those oil away and buy the right one than to use it.

NC TRACKRAT

When Brad-Penn first came on the market a few years back, they didn't yet offer 15W40. I inquired if I could blend the 10W30 and 20W50 to achieve the 15W40 and they said that it was perfectly acceptable. I use 15W40 in the both 993's and the old cars.

theiceman

I like this answer as I don't want to see this thread at the top for the next year 😉