Synthetic or conventional motor oil

[Oldroostman]

Was gonna dump the oil on my 2015 at 5000 miles just to get the break in particulates out.you guys recommend synthetic or rottella t 15/40.had 3 different 5.9,s always ran rottella or Mobil delvac no problems .

 

[AH64ID]

I am a synthetic guy myself but I generally run conventional for the first 9-10K miles and change the oil every 3K miles until then.

That being said I hear the OEM fill is Synthetic 5w-40 as the factory has no idea what climate the truck is going to.

 

[sag2]

Correct, factory fill is synthetic.

 

[Newsa]

I run synthetic amsoil. But alot do run Rotella T. Personal preference. They all do the job.

I've heard some getting temps up to 240°F+. Synthetic is more reliable at high temps in my opinion.

But those hot exhaust gasses are good for keeping the DPF clean

 

[Tuesdak]

How hard do you use the truck? DD, Towing? What is the outside temperature? Tuner on truck? Miles put on the truck for the 6 month or 1 year time limit?

Due to cheap fleet operators Conventional Rottella has the higher TBN and other numbers for extended drain intervals. Even more so then their synthetic Rottella. I have ruined conventional engine oil due to heat and/or hot rodding. So engine oil does have limits where synthetic has some advantages for extended high temperatures. You have to work the truck very hard in high heat say on 7% or higher grades that go for miles towing or crazy hot rodding to get there.

Cheap... Oil changes are expensive. Oil changes come out of my bottom line. So screw changing oil early as 'insurance' because that is a waste of money and good oil. What isn't a waste of money is UOA, getting oil samples analyzed at the lab. This tells me if I am pushing the oil too far or hard, if I can run it longer, and if anything is going wrong like a bad air filter or scuffed piston. From a 7 quart 6.5 turbo diesel needing oil changes at 2500 miles (more than 1 change a week) to the $100 oil change of 3 gallons used in the Cummins that can go 7500-15K miles year dependent - the oil changes cost money. I can understand break in oil changes at 500 miles after a rebuild, but, I don't bother with it on new engines.

There are several flavors of synthetic oil explained here:
https://en.wikipedia.org/wiki/Synthetic_oil

I have found that the choice of the oil filter for use beyond 3000 miles is way more important than engine oil selection. A bad filter will take your engine out quicker than oil failure. I have already found failures in high end filters like Bosch and Mobile 1 this past year on gas engines. Yeah Mobile 1 is made by Champion labs that is now part of the Fram group. So who makes the filter and who stands behind the filter's warranty is very important.

 

[Newsa]

I personally wouldn't use Rotella T for 15,000 miles in a hot or mountainous climate and towing more than 10,000 lbs.

It's good. But think about the temperatures. If I'm driving my Cummins hard enough to do a passive regen.....

I'm going with an oil that can withstand the Temps. Namely, a quality synthetic.

 

[Tuesdak]

Exactly - how close to the edge do you want to be? The other side of the edge is expensive!

We towed the limit of our 2008 Duramax 550 miles a day every workday on conventional Rotella. Extreme grades, Max GVCW, extreme 121 degree temps, Oh My! At the ~10K oil change reminder message the oil was near done and not really safe to push longer. (~10K was the limit of the oil life system under ideal conditions for that engine.) The cost to go synthetic wasn't in the budget and we should have used it due to low oil pressure alarms and other oil stress. Outside the factory setup we had a massive 2 quart Killerbee oil cooler added and this is the only reason the engine survived. We ruined the 250 and 300 degree F continuous rated oil cooler hose.

The oil was reformulated since we had that truck for exactly some of the above reasons and other fleet concerns.

 

[Mingoglia]

I'm curious why the factory uses sythetic? is there a reason? Most of the time only vehicles that "need" it will come that way from the factory. I also find it curious when I brought my '15 into the dealer they "tried" to put conventional oil in. I found out before it was done and told them I wanted "exactly what it came with".

 

[AH64ID]

I'm curious why the factory uses sythetic? is there a reason? Most of the time only vehicles that "need" it will come that way from the factory. I also find it curious when I brought my '15 into the dealer they "tried" to put conventional oil in. I found out before it was done and told them I wanted "exactly what it came with".

The factory has no idea when/where it will be sold.. that could be Arizona on a 115° day or Fairbanks on a -37° day.

 

[Cummins12V98]

I'm curious why the factory uses sythetic? is there a reason? Most of the time only vehicles that "need" it will come that way from the factory. I also find it curious when I brought my '15 into the dealer they "tried" to put conventional oil in. I found out before it was done and told them I wanted "exactly what it came with".

IMHO yes DO run synthetic but run 15/40 since you are not in sub freezing conditions all the time.

I run the 100% Synthetic AMZ/OIL 15/40. Did in the 11 HO also and had great Blackstone test results at 7-7,500 miles.

 

[Bob4x4]

extended intervals don't work well with the aftertreatment trucks due to fuel contamination.Is synthetic needed to meet standard oil change intervals? no says Cummins.That is good enough for me.I do not see oiling failures on the Cummins.If it lets you sleep better go for it.

 

[Mingoglia]

IMHO yes DO run synthetic but run 15/40 since you are not in sub freezing conditions all the time.

I run the 100% Synthetic AMZ/OIL 15/40. Did in the 11 HO also and had great Blackstone test results at 7-7,500 miles.

I ran 15/40 Rotella in my 2nd gen for the 13 years I had it. I never did run a Blackstone test though, despite getting a bottle years ago. I figured on my '15 I'd just stick with the factory fill until I get about 10k miles or so on it. Amazingly I'm about to turn 9k on it already.

 

[Cummins12V98]

I ran 15/40 Rotella in my 2nd gen for the 13 years I had it. I never did run a Blackstone test though, despite getting a bottle years ago. I figured on my '15 I'd just stick with the factory fill until I get about 10k miles or so on it. Amazingly I'm about to turn 9k on it already.

Nice! You have been getting a lot of windshield time!

 

[TCDiesel]

extended intervals don't work well with the aftertreatment trucks due to fuel contamination.Is synthetic needed to meet standard oil change intervals? no says Cummins.That is good enough for me.I do not see oiling failures on the Cummins.If it lets you sleep better go for it.

Its the extend intervals that the Synthetic producers promote, I stand With Bob4x4, Good gosch Ams thinks theirs product are equal to pouring gold.OK its good oil but its twice the price of others. Shop around you can buy Quality Syn oils for fair prices, run it 10K and drop it...Hmm look at FCA spec for 3.0 oil $60.00 PG...AutoZone had Pennzoil Ultimate for $28 P5L with $15 RB, What.... the last time I check the 6.7 & 3.0 all had internal parts that need lubrication NO different then 10s of million of engines. If My 6.7s or 3.0s or any engines I own use oil there gone or Re-done.

If you dump your oil every 5-7K use STD oil, if you run 10-15K use syn oil. Now if you live in cold or extreme cold or heat use syn oils, But whatever you decide change it regularly.

 

[Cummins12V98]

I will be running this fill of AMZ/OIL 15/40 until the truck says to dump and at that time I will do a Blackstone test including TBN. I will post the results.

 

[Newsa]

Its the extend intervals that the Synthetic producers promote, I stand With Bob4x4, Good gosch Ams thinks theirs product are equal to pouring gold.OK its good oil but its twice the price of others. Shop around you can buy Quality Syn oils for fair prices, run it 10K and drop it...Hmm look at FCA spec for 3.0 oil $60.00 PG...AutoZone had Pennzoil Ultimate for $28 P5L with $15 RB, What.... the last time I check the 6.7 & 3.0 all had internal parts that need lubrication NO different then 10s of million of engines. If My 6.7s or 3.0s or any engines I own use oil there gone or Re-done.

If you dump your oil every 5-7K use STD oil, if you run 10-15K use syn oil. Now if you live in cold or extreme cold or heat use syn oils, But whatever you decide change it regularly.

I used to think 12,000-13,000 mile oil change intervals was an extended interval.... until I read the owners manual of my 2013 Ram 2500.

Still feels like (12-13k oil change) it to me. I have never gone with the 20k intervals amsoil suggests.

But I was glad I had amsoil in my truck in 2003 when some college kids who didn't want to take their final exam unhooked my bottom radiator hose in my driveway. And I hadn't noticed it until I was flying down the highway.

The oil was burnt. And I changed it. But any other oil would have destroyed the engine.

 

[TCDiesel]

Ams is good oil, the price does not reflect its usage...Heck I did some work at MME Midwest Motor Express, They have power units with 500K + on 15/40w Rottella running 30K service intervals on all 2010+ Power. I know they hold 11-14 Gallons none the less, even if the company bought 275 gallon totes it would cost $300.00 just for the Ams per engine.

 

[Tuesdak]

Its the extend intervals that the Synthetic producers promote, I stand With Bob4x4, Good gosch Ams thinks theirs product are equal to pouring gold.OK its good oil but its twice the price of others. Shop around you can buy Quality Syn oils for fair prices, run it 10K and drop it...Hmm look at FCA spec for 3.0 oil $60.00 PG...AutoZone had Pennzoil Ultimate for $28 P5L with $15 RB, What.... the last time I check the 6.7 & 3.0 all had internal parts that need lubrication NO different then 10s of million of engines. If My 6.7s or 3.0s or any engines I own use oil there gone or Re-done.

If you dump your oil every 5-7K use STD oil, if you run 10-15K use syn oil. Now if you live in cold or extreme cold or heat use syn oils, But whatever you decide change it regularly.

This extended interval for synthetic* is no longer true. Per the TDR's last oil article the oil analysis on new oil has TBN and other numbers for longer drain intervals higher on Shell Rotella conventional oil. Their Synthetic has lower numbers. Truly due to fleet operators asking more miles from their cheaper conventional oil.

*Synthetic in a generic sense excluding Amsoil and the marketing fraud of Group III vs. Group IV (PAO) base stock. So true synthetic like Amsoil is IMO a different class of oil that can claim longer drain intervals.

Running the generic marketing term Synthetic I have seen better extreme performance in regards to extended high heat and engine loads as well as results with hot rod diesels. Using UOA I was surprised when a lowly 6.5 GM Turbo Diesel with a monster turbo and BD spool valve ruined it's own conventional engine oil in under 3000 miles. Ruined means it went up from 40 wt to 50 weight, used up the TBN, and high soot. Switching to generic synthetic eliminated the high heat from killing the oil in the UOA reports. Another 6.5 engine towing extreme grades scuffed a piston on conventional oil when it exceeded the limits of the oil.

Change the oil regularly would be at the 1 year or 6 month interval by your owner's manual or recommended mileage for the conditions. UOA can extend the miles you get on the oil. Sure you can instantly ruin your engine oil, but, aside of that early changes are simply wasting money. Other things deserve the extra attention like transmissions and rear ends.

Speaking of transmissions the local Boy Scout Troop uses a 2000 Dodge Dakota quad cab V6 pickup to tow a overloaded trailer with donated scrap metal to the yard 2-3x a week. It had AMSOIL put in the transmission at a young age and miles. Not changed since and has over 1/4 million miles on it. IMO wrong truck for the job and certainly the wrong engine as the AC doors go to defrost on the way back due to extended no engine vacuum pulling the slight grade on the way back... Granted they take is as easy as possible on it, but, you can only be so easy with that kind of load.