synthetic oil

[AH64ID]

Cummins kits = OAI Testing/Polaris Labs and that's who I've always had the best luck with. Just sent my first sample to them in over 5 years, so hopefully I'm still impressed with their reports.

I prefer a 5w-40 for the cold flow and high heat properties, but 10w-30 works for most owners.

 

[dannonebr]

To add some more info here, I had the oil changed on my truck at the dealer as I was still due a free one, so I took it. I recently had back surgery for my pinched sciatic nerve so I went to the dealer. They used Valvoline premium blue 5w-40 and recommended my next oil change at 5000 miles. In another note the surgery went well, I can take long walks again but still healing.

 

[crispyboy]

So does anyone have an opinion on Mobil Delvac 1300 blend 15w-40 oil? I have always used Valvoline 15w-40 conventional oil with 5k oil changes. The Mobil is much cheaper priced ($12.37) at my local Sam’s Club than what I can purchase the Valvoline oil. I can also get Rotella T4 ($15.66) for a little more than the Mobil but less than the Valvoline.

 

[Bug Out]

Take it easy on my guys, but I just noticed Walmart has a full synthetic Supertech 15w40. I had seen they carried conventional 15w40, but not the full synthetic. Not sure if this is a newer item or I've just missed it. At around $15.84/gal it's the best deal on full synthetic I've seen. Is anyone running it? Reading to forum it seems Rottela T6 is the gold standard and the only CK4 rated oil I've seen carried locally. Most of the other brands are rated CK4/SN and from my reading the SN means it can be used in gasoline engines which leads me to believe it's a step below CK4. That said, I don't like the exhaust smell from T6. I mostly use our truck for pulling our trailer and don't want to hear the wife and kids complaining about the smell.
We put about 6K miles annually so not much. A mechanical told me once, clean oil is better than any fancy oil. I don't feel comfortable running oil over a year so for me that works out to one change on a full synthetic or two on conventional. I am partial to Costco Kirkland's brand products, so I've settled on two oil changes with filter change every other oil change. On sale, which it is this month, it's around $26 for 3 gallon box, best deal I've seen anywhere on conventional oil. I put the Geno's femco oil drain valve and has made oil changes a breeze with no mess.

Super Tech Full Synthetic Heavy Duty SAE 15W40 Motor Oil, 1 Gallon - Walmart.com

Back in the day when backpressure vent tubes were directly out towards the ground etc, the "Smelly Rotella" for the first 500 miles was heaven... Can't smell a thing now....

 

[AH64ID]

So does anyone have an opinion on Mobil Delvac 1300 blend 15w-40 oil? I have always used Valvoline 15w-40 conventional oil with 5k oil changes. The Mobil is much cheaper priced ($12.37) at my local Sam’s Club than what I can purchase the Valvoline oil. I can also get Rotella T4 ($15.66) for a little more than the Mobil but less than the Valvoline.

Considering this is a thread about oils for the CGI engine, yes there will be an opinion on any oil in 15w-40 as it’s the wrong viscosity for the engine.

For older engines I’ve never heard anything bad about Mobil Delvac 1300 in 15w-40. If your engine has been on a diet then 5K miles seems a bit short for OCI’s unless you’re timing out.

 

[crispyboy]

Yes I have an older 15w-40 engine. I figured it was a good time to post about this since motor oil was the subject.

 

[Grumpy8811]

Is it worth the extra cash to use Rotella synthetic or Rotella blend ? been using the blend for 50k

hard to say but using synthetics usually makes the vehicle owner feel all warm and fuzzy while using the cheaper stuff seems to belong to a group of people otherwise known as realist's.

 

[Grumpy8811]

Considering this is a thread about oils for the CGI engine, yes there will be an opinion on any oil in 15w-40 as it’s the wrong viscosity for the engine.

For older engines I’ve never heard anything bad about Mobil Delvac 1300 in 15w-40. If your engine has been on a diet then 5K miles seems a bit short for OCI’s unless you’re timing out.

I've often wondered why 5W40 is seemingly OK but 15w40 is not? Simply because about the only time that 5W oil actually behaves any different than 15W is at or below Zero Degrees F.

You can also wonder if 40W at 212F is acceptable, as in 15W40 or 5W40 why is 30W at 212F also acceptable.

Much like the medical profession, in the end I think Mopar just blamed the issue on the oil and not on underlying causes.

 

[Ozymandias]

Even at room temperature the viscosity of the 15-40 is considerably higher then the one of the 5-40.

 

[Grumpy8811]

yeah, this is the viscosity charts for 5-40 on top and 15w 40 on the bottom.... by 20C 68F the difference is small enough not to make much difference. .. my personal opinion is Mopar should have just specced using a synthetic 5w40 for everybody based more on the idea that 5w40 are all synthetic and composed of higher quality base stocks than conventional oils.. because the difference between 15w40's and 5w40 is negligible or non existent at normal operating temps..
other thought might be why did they use needle bearings in the lifters instead of a bushing like they used in some of their different engine cam followers?

I know Mopar mentions deposits as being the cause but I have often wondered if their recommendation is a band aid where they dont really know what the problem is so they blamed it on the oil.


temp/

 

[AH64ID]

I've often wondered why 5W40 is seemingly OK but 15w40 is not? Simply because about the only time that 5W oil actually behaves any different than 15W is at or below Zero Degrees F.

You can also wonder if 40W at 212F is acceptable, as in 15W40 or 5W40 why is 30W at 212F also acceptable.

Much like the medical profession, in the end I think Mopar just blamed the issue on the oil and not on underlying causes.

Have you looked at the specs? There is a difference at 40°C (104°F) that only gets more distinct as the oil temperature drops.

 

[Grumpy8811]

Have you looked at the specs? There is a difference at 40°C (104°F) that only gets more distinct as the oil temperature drops.

biggest diifference in the 2 is below 20C.. above that temp the differences start to amount to a rounding error..

but I digress, my main thought it why do they think you can't use 15w40 in a hot climate? the deposit thing should not have any difference when it comes to viscosity as that is more of the subject of additives and add packs are vastly similar across any brand from bargain basement to fools gold.. Other thought is the matter is also how long does one of the engines operate at low temps compared to normal operating temp? Because the viscosity thing sounds more like hyperbole than an actual thing, unless these engines suddenly became delicate because of hydraulic roller lifters and a CGI block.

 

[AH64ID]

A rounding error? Just looking at one series of oil the 15w-40 is 19% thicker at 40°C than 5w-40.

It’s not the block, it’s the lifters.

I do think that they would be just fine with a full synthetic 15w-40, but that’s just a theory I’m not willing to test on my own truck.

 

[Grumpy8811]

A rounding error? Just looking at one series of oil the 15w-40 is 19% thicker at 40°C than 5w-40.

It’s not the block, it’s the lifters.

I do think that they would be just fine with a full synthetic 15w-40, but that’s just a theory I’m not willing to test on my own truck.

which goes back to my question of what is the problem with the lifters that a 5w40 or 10w30 avoids but 15w40 gives?

little different story here, but along the same lines... Toyota specs some ultra low viscosity oils for their American market cars but if you buy that same vehicle with the same engine in a different country they spec a wider variety of lubes... so same thought should apply to 10w 30 versus 15w40 or 5w40... where is the difference? it isn't alot.

anyway you look at it, none of us are going to be able to answer it and 5w40 is so readily available as for me to not suggest anybody use 15w40, just that I think Mopar literally threw that out as a solution and is hoping that fixes it as it doesn't make alot of sense when it comes to " blaming deposits" when you know that 10w30 Rotella T4 doesn't have a different additive package than 15w40 Rotella T4.. or Delo or Delvac or Premium Blue for that matter.

 

[AH64ID]

which goes back to my question of what is the problem with the lifters that a 5w40 or 10w30 avoids but 15w40 gives?

Cold flow properties, nothing more or nothing less.

 

[Grumpy8811]

Cold flow properties, nothing more or nothing less.

alright, you say Cold Flow properties whereas Mopar said " deposits"... Quote them here...CAUTION! 15W-40 grade oil CAN NOT be used in any 2019 model year or newer 6.7L equipped vehicles due to the new designed valve train of this engine. If this oil is used, it will cause deposits to form in the Hydraulic Valve Lash Adjusters leading to undesirable noise, and/or engine damage. https://static.nhtsa.gov/odi/tsbs/2020/MC-10178698-9999.pdf

like I asked, what deposits are formed by 15w40 that aren't formed by the other viscosity grades in consideration of the idea they all use similar formulations and additive packs?

 

[AH64ID]

Mopar doesn’t really say anything different. The only time 15w-40 and 5w-40 are different is when the oil is cold.

As far as the actual deposits I haven’t actually seen them to know.

 

[Grumpy8811]

Mopar doesn’t really say anything different. The only time 15w-40 and 5w-40 are different is when the oil is cold.

As far as the actual deposits I haven’t actually seen them to know.

I know... Mopar says " deposits" in that Service Bulletin.. but it doesn't seems reasonable as there is little difference in additive packages between
any viscosity grade nor has anyone ever made the claim that 15w40 leaves deposits that 5w or 10W don't... so what were the " deposits " from?

or is it just Mopar bull? I'm thinking bull.

not disagreeing on cold flow, just the deposit thing..

 

[johnmyster]

Mopar doesn’t really say anything different. The only time 15w-40 and 5w-40 are different is when the oil is cold.

As far as the actual deposits I haven’t actually seen them to know.

5w and 15w are different everywhere below 100 C.

 

[AH64ID]

5w and 15w are different everywhere below 100 C.

Exactly