Oil Viscosity this time of year?

[bobby_the_one]

i was going to put castrol GTX high mileage 15w/40. i know ppl love elf on here but will it really make that much of difference? what visc.should i b looking at?

 

[BRUN]

15W-40 is the wrong grade for a 172, use 5W-40 which is the correct grade and will flow better in the cold weather

 

[bobby_the_one]

ok thats great thanks for that!

 

[Lunner]

As above the first number is the viscosity when cold (20 deg c iirc) and the 2nd number is the viscosity at 100 deg c

 

[edde]

5 or 10 weight oil are fine 10 is ok donw to -20 though wheras 5 weight is ok down to -25 its better to use 5 though on choice.