Switching to 10w30 synthetic? Mixing 10w30 syn w/ 15w40?

Joined
Nov 23, 2021
Messages
3
Have an oil change coming up. Recently came into a buttload of Delvac syn 10w30 (see below) via a foreclosure sale.
Been running the Walmart Super tech 15w40 since 150k (0-150k = Rotella 15w40). Would like to eventually transition to the Delvac if it’s not a problem but still have a 2 gal jug of the Super tech 15w40.

Would it be a problem to mix 8qts Mobil Delvac Extreme synthetic blend diesel engine oil 10W-30 with 7qts SuperTech 15w40 Heavy Duty Diesel engine oil?

Or should I just go straight Delvac synthetic IF it’s ok to even make the switch.

  • 2003 Ford F250 SuperDuty (165k miles)
  • Live in Louisiana
  • Just a beater - Lite mileage (>15m per day)
  • No hauling, heavy loading, etc…
Thanks for any advice!
 

craftyone

Thread starter
Joined
Nov 23, 2021
Messages
3
I'd do that all day long. I mix oils just about every oil change depending on what I have around and what season it is.
Thanks! Yeah if I lived in Alaska or North Dakota I’d probably look more into it but I think for my location and limited use I should be good. Plus I’d be 100% synthetic the next change and I always thought synthetic was the was to go with an older engine.
 
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