Just wanting to get everyone's opinion on using different oils for an oil change. I have 8 quarts of Mobil and 4 of Rotella (all synthetic). Any issues with mixing these on my next oil change? Thanks.

 

I did do a change with two gallons of CI 4+ and one gallon of CJ4 rated oils when the CJ4 just came out. These were the same brand of oil just the different rating. Check the bottles and see if it says compatible with other like oils, I have seen this when people needed to add a quart, the new bottle said something about being compatible. As long as they are diesel rated oils I would think they would be alright but others may know something I have not learned.

If you are uncomfortable doing it just go buy enough of one brand to do the change.

 

You will ruin the engine, radiator, grille and both front tires doing such a strange thing.


A military standard requires all oils of same weight and spec to be compatible in a engine. I am not sure that 100 % true but close enough to keep you out of trouble. You will be fried in Epson Salt if you do it again.

 

I wouldn't do it in my current truck but I had an 83 Ford gasser and I dumped what ever was handy in that old truck. It had 120,000 miles on it when I bought it and it had about 200,000 miles when I sold it, still runnin' strong. The only thing I done to that truck was replace the brakes and alternator.

 

See, right there, it can cause the alternator and brakes to fail early!!!!

Now, for a serious answer, all these oils are required to be compatible. So it is acceptable.
However, It is not recommended.
It was once told to me that an oil is a specific formula or recipe.
You usually end up( by mixing) with an oil that is below grade for either oil if used straight.
My brother in law once had an olds that he put anything he had in it. By 80,000 miles it was tired and using a quart in 400 miles. A brother bought the car, asked me to rebuild it. I put him off long enough to get him using a top grade oil for 3,000 miles. It cleaned it up and he drove it for 250,000 miles.