Hey, I done an oil change a few months back and i put in 15 40, but now ive added some 20 50 because thats all i had, and my 15 40 ran out.

Will this cause me any problems ? I have nasty thoughts of it not mixing etc

Tsk shame on you! Especially with Sewells just around the corner!

Effectivly you've just made a multigrade but 20w50 is too thick at low temp and too thin when hot. Hope you ain't put too much 20w50 in.

Hehe, the guy who owns it is my old wood work teacher from school.

I aint put loads in, just enough to take it off just under min!

10w 40 is much better

Mixing 15w 40 with 10w 40 won't do much harm will it???

No dont think so IIRC, a few on here have mixed and matched, dont think 20w 50 is ideal though

itll be alright in the older engine