I only have 5 quarts of Mobil 1. Can I mix another quart or so of Penzoil or Castrol of the same weight? I cannot get more Mobil before shipping my truck back to the states in a week or two.. Thanks.

 

assuming the Mobil 1 is not the synthetic, I do not think it would hurt to mix a similar oil of the same weight. The Pennsoil is a different type of oil in that it has a parafin base. I would not mix it.

 

Penzoil BAD Quaker state BAD!!! It's not a good idea to mix them because of different additives that may be in different brands. You can but do you know for sure they go together? Oil's cheap just pick up another quart at walmart. edit: didn't see where you were. You'll run fine on 5 quarts. That is all I run in mine and they call for 6.

 

I thought all MOBIL 1 was syn???

 

I don't know, maybe it is. If so, don't think you should ever mix dino with synthetic. I know there are blends, but I would leave "blending" to the oil companies.

 

Yes, I was talking about using both synthetic brands.

 

Really? I've never heard of someone running less oil than called, especially an entire quart! I would be far too afraid to damage something... how did you even know that would be safe in the first place?

 

It's still on the dip stick and alot of Lightning guys do it. By reducing the level of oil they reduce the oil ingestion back into the motor.
It's called Tolerances. The OEMs build them in for people that don't check their oil regularly. Have you ever paid attention to how much oil you get out of the motor after 5K miles? Not the same amount you put in!!!

Don't quote me but I think the motors won't show low oil/no pressure until there is only 2 quarts or so left in the motor.