Oil/filter questions...

[Bluebird]

Wally world out of Mobil-DelVac 15/40, so I got Rotella 15/40.

1. If the truck should need some oil before the next change (4500 mile intervals), could I add some DelVac to the Rotella, or is that not recommended?

2. When I went to take the old oil filter out, the oil level in the filter was only 1/4 full, (enging temp was normal, just got off the freeway, oil pan drained about 15-minutes). Does that indicate any type of a problem?

Thanks in advance for any experienced replies



Patrick

 

[raksasa]

From issue 55 of the TDR:


3. I switched from Brand A to Brand B, and now my engine uses oil.

I doubt it! Oils are tested to make sure they can be mixed with other oils without problems. Chemistries are not that drastically different these days. If you noticed a difference when switching oil brands, be certain that:​

a. You are comparing oils which both meet the same

performance and viscosity specifications.

b. You didn't already have excessive oil consumption, but simply hadn't noticed it prior to switching oils. When you try something new, you become more aware of performance. ​

Regarding the filter... sorry, no idea if that's a problem. ​

​

 

[JLEONARD]

I have mixed oils in the past, but I only do it in an emergency so to speak. My policy is to stick with the same brand and NOT to switch back and forth between brands on a regular basis.

Yes make a change if you want but continue with that new oil.



That's my personal policy based on what little I have read over the years by various authors/experts on the subject.

 

[Greenleaf]

You can mix a top quality base stock oil with a oil of lesser quality base stock and it will improve it only because you just introduced a better oil to the lesser oil.



You need to know your oil TBN. A top of the line TBN oil may be low when new, say 10. BUT... ... ... ... it will remain there for a long long time and not wear out at a rapid rate. Mixing a low quality oil with a higher quality will not **degrade** the newer oil. Only **delute** it. I assume you always use an API rated oil.





The oil inside the filter in our engine will drain back. Thus, no problem what-so-ever.



Oil consumption? A higher quality oil will lower oil consumption due to the ability to seal compression better. A lower quality oil would tend to be consumed at a higher rate.

 

[KOG]

Rotella and Delvac should mix with absolutely no problem.