I was checking out Bob the Oil Guy and he was showing pictures of both regular and synthetic oil. The synthetic oil showed lots of trapped air which is not good. I had changed to synthetic on my last truck but don't know if I want to in this truck. From what I have been reading most of you owners have gone to synthetic so I am wondering which is best for the truck
Thanks
Pam

 

I run both synthetic and dino in my truck. In the fall, I switch over to Rotella-T 5-40W (easy to find at WalMart) and in the spring I switch to Delo 15-40W (easy to find at COSTCO). I principally change to the synthetic in the cold season to cure what is referred to here as the "romps" at very cold temperature start-ups (below zero occasionally) and to improve cold-weather mpg. My feelings are that so long as you are using a high-quality, diesel-rated oil, dino or diesel, your truck will love it. I don't recall the picture at BITOG, could you post the url?

 

IMO it is not necessary. Lots of guys run synthetics and bypass filters but I don't. I run Delo and change it every 3-4k along with a new Wix filter. The truck has well over 200,000 on it and still runs very strong.

If you hate changing the oil then maybe look into some longer lasting oil / filter system.

 

Here is the page I was reading. It was talking about Lucas but showed lots of white in the synthetic oil. At least that is how I read it.
http://www.bobistheoilguy.com/images/lucas/lucas.htm
Pam

 

Hey Neal. I was typing my post as you replied. I didn't intend to imply that what you do is not necessary. I know it gets colder where you live than here and the romps are a real condition that is addressed as you stated.

Andy

 

Just some questions and thoughts that come to mind.

- What does the entrained air do that's bad?
- Oil with entrained air has a larger volume. Fact. Harder to pump? So hard to pump that it doesn't get where it needs to? Does the increased volume compensate for pumping difficulty by spreading the thin oil layer over a larger area?
- If the air-laden oil is harder to pump, does that necessarily mean shorter HPOP life? or just that not as much volume gets to its desitnation at every stroke of the pump?

I don't honestly know the answers to these questions. The entrained air in the ol creates a wonderfully dramatic visual illustration that the situation actually exists, but how much science exists regarding whether or not the entrained air is truly a problem?

After all, we want to get lubrication from the oil we use, and we want the oil to last as long as possible while performing this job of lubrication.

Thinking about it more, perhaps the air is a problem in our HPOP system due to teh high pressures that the pump is trying to create. Maybe with the entrained air, the HPOP can't provide adequate pressure for optimum injection??

It would be good if someone can provide some facts about this issue of entrained air and what the measured impact of it is in our PSD's.

 

We might have to get Ernest on this one.

 

Duct Tape that oil so it sticks better!

 

First entrained air is at the molecular level and is not the same as large pockets of air that you can see such as in oil foaming. It is more common to discuss entrained air in fuel than in oil.
Second you can rest assured that most HDEO's, synthetic or not, have an amount of anti-foamant additive to combat oil foaming in modern diesel oils. The BITOG article and testing, which is rather dated now, showed the effect of one common oil additive that negated these anti-foamants and allowed the oil to foam when run through a gear set.
Early into the introduction of HUEI type injector systems there was at least one very commonly used HDEO that was reported as to not have sufficient anti-foamant in the formula, and poor running and scored injectors was the result. For a while Navistar or International had a TSB to add anti-foamant to the crankcase oil to correct issues with foaming, this seems to have corrected in updated formulations of major HDEO producers.
Foaming in the oil means that large amounts of air are introduced and carried in the oil, not just entrained but at a macro level. Hence the description of foam. A common example is when the sump is overful and the crank spins through the oil whipping it up exactly like whipping a liquid with a kitchen beater. Air is compressable, orders of magnitude more than oil or hydraulic fluid. Air in the oil in such a merange lower oil pressure, and displaces the lubricant such that in bearings they can starve from lack of lubrication due to lack of sufficient oil, and in injectors esp. heui type which rely on high pressure of relatively non-compressable fluid to operate leads to injector timing and low injection pressures with incomplete injection issues along with a lack of lubrication of the injector barrel with foamed oil, since the plunger first must compress the air before opening pressure of the nozzle is reached.
All diesel fuel has some entrained air as the fuel molecules are more polar in nature and an air molecule can become attracted to the fuel molecule and 'hitch a ride' through your fuel system, in general oil is less polar so does not have the same affinity to have air entrained in it that fuel does. But like I said, this is not foam as you cannot see entrained air. entrained air merely lowers your energy content and is mostly as incompressable as the molecules surrounding it, air bubbles in foamed liquid is compressable and not only lowers energy content but creates large voids in the liquid.

 

Excellent explanation, dsldrvr. Thanks. Rep points for addressing such a complex issue so concisely.

I can also now see that even if air-entrained oil covers a larger surface area, there is still substanially less oil for both lubrication and cooling, which would result in the lubed parts building up more heat as compared to if they were lubed with airless oil.

Leads me to this though... are you saying, then, that the current oils in use are not an issue today? If so, does that same position apply to both dino and synthetics on today's market shelves?

 

We be in agreement !

 

Hi F250 and thanks, AFAIK oils fresh out of the bottle the answer to your first question is yes and yes to the second question as well. There are two tests that have been specified since at least CG rating, the ASTM D892 foam test and the oil aeration test. The second test is specifically for HEUI systems, and i notice the test method and limits were changed with the advent of CH-4. So all present OTC CI-4 and CJ oils have to pass these basic levels of performance, synthetic or conventional. From real world observations in the past I have found that the synthetic formulations actually hold up better/last longer in their capabilities to maintain anti-foam and anti-aeration tendencies than the conventional types. This may be due to a synergystic effect between the anti-foamants and better quality dispersants in the synthetics or just that the synthetics tend to produce lower levels of insolubles and therefore stress the dispersants and overload the anti-foamants less. There were certain conventional (dino) oils in particular in the past that I could swear that they seemed to lose the aeration inhibiting qualities faster than others as use increased but couldn't say for sure without specific lab testing. At least that International bulletin i mentioned earlier seemed to confirm my observations. However with the advent of the CJ spec, the poor performers all seem to be getting a reformulation uplift with upgraded dispersant specs and the new formulations are supposed to be significantly better. We will see. Those that have delayed in upgrading to the CJ-4 spec have all been the better performers in this regard in the past I note.
I guess the moral is make sure you use the proper API service grade lubricant, and don't overfill your crankcase by a whole lot.
P.S. You can find the test limits at least for the API specs here:
http://www.infineum.com/information/tables.html

 

I just did the same on my last change. I'd been running 5-40 synthetic year around for I think a few years now because of the romps I experienced during a cold winter. Again, I agree with the quoted above. And I tell you what, my truck sounds dang good on the Delo 15-40. Good enough that I'm going to use it through my October pheasant hunt in ND to see how it performs in some cold weather.

As a note, I ran Rotella dino 15-40 before switching to the Synthetic and I believe it sounds better on the Delo. And.........my Dad's 99 with nothing more than a 4" turbo back MBRP with muffler and a 6637 sounds great on dino 15-40. And that's on CarQuest brand.

Again, I believe in the quoted above.

Hope this helps