Left over M1

[gfh77665]

I have two left over Mobil 1 5w20's, and would like to mix it with 3 more of something to achieve a near 5-30 for a high mileage 2000 Chevy truck. Would mixing in two 5w30 oils and one 15-50 equal a "7-30" weight? (I averaged the #'s).

Would mixing the above with Mobil 5000 conventional create an OK oil change? Thanks for your advice.

PS: It gets really hot where I live...

 

[bmwtechguy]

I would not hesitate to use 2 of the 15W-50 qts. for this mix, especially where you live. You could mix with the Clean 5000, but then you might want to change the whole deal out 5000 miles later.

 

[gfh77665]

OK, thank you. So, mixing the thin 5-20's with a thick 15-50 (or two) won't be detrimental to the engine in any way? Also, I do 5000 mile OCI's. Appreciate the advice!

 

[hate2work]

Well, it's funny because usually when someone asks about mixing/blending oils, the standard answer is "No, they have different add packs, they won't blend well".

But then you have several members who say they have done this for years with no bad results.

So...who really knows...

 

[bmwtechguy]

No harm. I do this with odd quarts of oil different viscosities to use them up. Never had a problem, even in BMW's. I weight it towards heavier viscosity going into hot weather and thinner for cold weather. As far as mixing brands, I try to stay with the same brand whenever possible, but do mix across oil types and viscosities within that brand or brand family such as an Exxon-Mobil mix, or SOPUS brands such as Shell, Pennzoil or Quaker State.

 

[Mark888]

I don't think there is any problem blending oil, but the 15W-50 may be a bit extreme to mix with the 5W-20. I would try to keep the highest one at 10W-40, 5W-40, or 0W-40 at most.

 

[bmwtechguy]

How is mixing with 15W-50 extreme? He'll end up with somewhere between 5w30 and 10W-40, which in a high mileage Chevy truck in SE Texas heat would be ideal, IMO.

 

[Mark888]

Originally Posted By: bmwtechguy
How is mixing with 15W-50 extreme? He'll end up with somewhere between 5w30 and 10W-40, which in a high mileage Chevy truck in SE Texas heat would be ideal, IMO.

Mobil 1 15W-50 is a slightly different animal compared to other Mobil 1 oils in terms of additives that it has for older valve train designs. It is API certified SM, but lacks any other certifications such as ACEA.

If it were me, I would probably use something like 10W-40 High Mileage Mobil 1. But maybe I over-reacted and you are right that one quart of 15W-50 mixed in with the others probably will not hurt. Actually, one quart of Mazzola Corn Oil probably would not hurt too much if mixed with 4 quarts of Mobil 1.

 

[TexHawk]

It seems like I read where someone mixed oils with vastly different viscosities and the engine developed a knock.