Ok to mix grades?

[lincolnjohnny]

Currently using Amsoil 0W-20 ASM in a 1991 Lincoln Town Car(4.6)147K. Used 1qt first 1.5k and now at 3.0k I need another qt. I think that I used too thin of an oil. Might be burning, might be leaking, to cold to investigate.Previously was using Mobil 1 5w30 and would us 1qt every 4k.
Could I just add a qt of Mobil 1 5W-20? My thought is that this would "thicken up" the oil a bit. Any harm in mixing brands of synthetic and grades?

johnny

 

[Spector]

No problem. Been mixing a 10w40 1ith 5W30 for a while now and also a 15W40 WITH A 5w20. You will not have any problems!

 

[simple_gifts]

Quote:

Could I just add a qt of Mobil 1 5W-20? My thought is that this would "thicken up" the oil a bit


How can you be sure? Are you sure 5W-20 is thicker @ temperature than ASM?

 

[ToyotaNSaturn]

You could mix a qt of 5w-20, but it won't do you any good. Like Spector, I suggest a thicker oil in that engine.

 

[Rock_Hudstone]

Originally Posted By: lincolnjohnny
Any harm in mixing brands of synthetic and grades?
johnny

Ideally at least blend within the same brand to avoid clashes in the additive packs. For example, Mobil 1 5w-20 with Mobil 1 10w30, etc. However, for a one time deal it's nothing to be concerned about.

By the way, why such thin oil in the first place? A good 5w-xx oil should be fine for all but the most extreme low temps.

Personally, with that high mileage I'd consider running a 10w30 in all but the coldest months.

 

[Triple_Se7en]

I would use one quart of 10w40 conventional. Then when you change the oil next, switch to 5w30 Amsoil XLM. Your engine may prefer a thicker viscosity - plus it may prefer Group III to Group IV.