Synthetics question

[Mtngoat]

I am planning to put synthetics in the axles and transfer case, but am not sure about the engine or transmission. Seems like with dino oils for the engines there is always a mileage and/or months recommendation (4000mi or 6 months for example).

I understand synthetics is supposed to last a lot longer than dino, but does the amount of time its in the engine make a difference? I don't put thousands and thousands of miles on my truck like some tdr members do.

The way I asked this question seems confusing to me so let me know and I'll to figure out another way to ask... But I figure you guys have seen it all and will know what I'm asking. Basically, as I don't really rack up the milage, is it beneficial to use synthetics in the trans and engine? Thanks!



Robin

 

[RustyJC]

Robin,



I'm probably in the same boat as you. I've used synthetics in all my vehicles since the mid 1980's. I currently use synthetics (Mobil I) in my wife's Durango and my Acura 3. 2 TL-S, and I use Royal Purple synthetic 85W-140 in the rear axle of the 3500. In the Cummins, however, I'm using Delo 400 15W-40.



The reason is that our truck only gets about 8000 miles per year usage - we took delivery on 8/15/01, and the truck has 11,800 miles on it. We use it almost exclusively to tow a 13,500 lb 5th wheel (21,180 GCW versus 21,500 GCWR), so we work it pretty hard when it is used, then it will sit in the garage for a month or two except for weekend drives to keep the batteries charged.



I choose to change the oil and filter at 3000 - 4000 miles simply because our truck does sit idle so much of the time. With changing temperatures and high relative humidity here on the Texas Gulf Coast, condensation can be a problem, and I feel better dumping the contaminants every 6 months.



That's just my choice based on the usage profile of this truck. YMMV.



Rusty

 

[Pit Bull]

Robin assuming that your CTD is broken in and has over 20K miles on it you can start using synthetics. I use them in the wifes Toyota Landcruiser because she only drives 8K miles per year. I figure when a vehicle sits for days without being started it is better to use the synthetics. I still change the oil and filter based on the manufactures recommendations. Now on my CTD I drive it everyday so I use Rotella T 15w40 and change oil and filter every 5K miles. I drive the CTD around 1500 miles a month. On the transmission I would ask Bill K what he recommends since you have his modifications. JMHO

 

[Mtngoat]

I talked to Stefan at DTT and he advised they have no problem with synthetics, Also to do the service at the same intervals as usual.



Robin

 

[DocStressor]

Good Question

Only oil analysis can tell you how well your oil is holding up under various conditions. I once went 11 months with less than 7K miles with Amsoil 15W-40 synthetic. The truck sat for several month long periods while we were away. The analysis showed more iron and silica than I usually see at 7. 5 K, but the oil was generally ok. The Mobile web site (for whatever that is worth) says that there is no advantage of synthetic over conventional base stocks for engines stored for long periods of time. I tend to agree. After a couple of day, enough oil drains off the metal parts to allow oxidation of the metal to occur. I don't buy any of the speculation that the ester components of synthetic oils or blends "cling" to metal better. They might make a difference over night, but not during long periods of inactivity. Synthetic and conventional oils use pretty much the same anti corrosion protectants, particularly in heavy duty diesel oils.



There may be no difference between conventional and synthetic oils if an engine is only driven say 2000 miles in a year. But the difference may be significant if the engine goes say 5000 miles per year. You should find out for yourself with oil analysis.

 

[Hohn]

This is an interesting topic to me, so much because I STRONGLY believe that there should be other recommendations for oil change intervals other than mileage. All miles are not created equally.



3K highway is nothing at all, especially if you did it all at once. 3K of trips all less than 5 miles is much harder.



I am a big believer in synthetics. I use Delo in my Cummins though. I do frequent changes because of my short trips, and the delo is more economical.



Most of my driving is very stop and go-- my drive from home to get on base is about 8 miles. Then I do some short trips on base (often less than 3 miles) and go home.



My feeling is that a syn would protect a lot better in my situation, where the truck sees lots of stop and go, but never sits for more than 4 hours or so.



In your case of having the truck sit for extended periods, I personally would run Delo with a bypass setup. If you live in an area where there is a lot of humidity, then you will want to run the engine more often to burn off some moisture.



In my case, I take the truck out at least once a week and run it hard. Once it's up to temp, I drive it like a stole it with one WFO run after another. This is not only to burn off the moisture, but also to help break the engine in since I only have about 8500 miles on mine.



Hohn

 

[amsoilman]

In my 94' CTD, I traveled 105,000 miles in a period of 5 years 3 months. I was using the Amsoil brand 15W-40 full synthetic engine oil along with a by-pass oil filteration system. I did on oil analysis every 10,000 miles. Each analysis that came back indicated the oil was still suitable for continued use.



The bottom line as far as I'm concerned, is the fact that with a good filtration system, high quality engine oil, and the use of OIL ANALYSIS, you can safely extend oil drain intervals.



The BIG thing is the oil analysis! This tells the internal condition of the Engine, as well as any contaminants, such as fuel, water, glycol, acids, or dirt.





Wayne

amsoilman

 

[DocStressor]

Are We Helping?

After re-reading this thread, I don't know if we are being helpful or just confounding the issue. Maybe we need more info.



Mtngoat: Do you drive your truck on long trips and then let it sit idle for periods of time? Or do you accumulate low miles because of many frequent short trips?

 

[Mtngoat]

It does a lot of in town driving and some 100 mile trips occasionally, and 3-4 times a year will haul the Jeep on the trailer to Arkansas or Colorado. No, it does not sit for a long time, 2 days would be the most it sits unstarted. .



Robin

 

[Hohn]

BAsed on that usage, I would say you are a good candidate for synthetic. I would run 15K intervals with the filter at 7500. You could go longer with bypass.



Don't switch to syn until you are good and sure that the engine is broken in. I am not there yet, but trying to get there soon!



HOHN

 

[DocStressor]

Yep. Hohn's got the plan for you. But I wouldn't go more than 1 year beteen changes without a bypass filter. We have open crankcase vents. So some dirt is going to get in there just as a function of time. At least that is what I have been seeing in mine.

 

[Mtngoat]

I would think it is broken in, it has 40K miles, however the former owner pulled alomost nothing with it if at all. .



Robin

 

[Hohn]

40K you should be just fine. Owner's manual says 20K. BTW-- it might not be FULLY broken in (which can take 50K or more on these engines), but it should be easily broken in enough to where you can switch to syn.



Some people have reported that the engine kept gaining fuel economy and using less oil almost until 50K! (THEN it was broken in. )



Hohn

 

[Texas Diesel]

Lots of good info here:



https://www.turbodieselregister.com/forums/showthread.php?s=&postid=608526#post608526

 

[Pit Bull]

The Oil Report, Blackstone Laboratories'

Spotlight on...

Oil Brands



No matter who you are or what your oil analysis needs are, you have undoubtedly faced the question on everyone's mind these days: What type of oil should I use?

Many people have very strong loyalties to certain brands of oil. They'll swear by their favorite brand and assure you that anything else is bound to ruin your engine. But we're here to dispel that myth. After nearly 20 years of testing oils from thousands of different engines and industrial machines, we have discovered an interesting fact: it doesn't really matter what brand of oil you use.

But wait! Before you dismiss us as heretical, listen to what we do recommend. We always suggest using an oil grade recommended for your engine by the manufacturer and a brand that fits your budget. The grade of oil is much more important to performance than the brand of oil.

In fact, here's another little secret. The oils you can find at any mass retailer are actually name-brand oils, but with the store's label on it. Think about it. A retail store is not in the business of manufacturing oil. They buy their oil from the big oil companies and put their name on the bottle. The only difference between the "generic" brand and the name-brand oil is the name on the bottle and about 50 cents per quart.

We analyze oils from our personal use engines (right down to our lawn mowers) religiously. We tend to choose oils that do not contain additives that can get in the way of elements we want to see in the analysis. For instance, some light, multi-grade oils use compounds of copper and/or sodium as oil additives. The copper additive masks brass or bronze wear from the engine. Sodium additives can mask anti-freeze contamination.

If you want to see for yourself which oil is going to perform better in your engine, we recommend a test: run Brand A in your engine for a set number of miles or hours and have a sample analyzed. Then run Brand B in your engine for the same amount of time and have that oil analyzed. You can compare the results for yourself, side by side, to determine which oil is best for you.

 

[Texas Diesel]

Good point PitBull, I have always wanted to compare oil analysis numbers and see if a peticular brand really performs better than another.



MTNGOAT, something else to consider here, no synthetic oil run or extended drain Cummins has topped 1,000,000 miles, there have been plenty of dino oil/OEM filter/regular changes Rams that have. Extended your drain intervals beyond OEM will void your factory warranty, read your owners manual. Some have reported successfully fighting back and having their warranty reinstated but it is still a risk you need to weigh against the benefits of extended drain intervals.

 

[Hohn]

Simple explanation

There's a simple reason that all the million-mile rams have been run on dino oil.



In order to reach that kind of mileage, you have to be running the truck all the time. It's rarely turned off, and the miles are highway miles.



Thus, these miles are the easiest you can imagine. Yes the engine is working hard, pulling a heavy load, but it's startup and shutdown wear that is hardest on an engine. Being on the highwway all the time is an engine's dream, since it's easiest on it.



Thus, since they are racking up all these miles, many of them don't want to spend the $$$ to run a synthetic. They don't run extended drains because they are old fashioned guys who don't mess with something that works. So if your truck lasts with Dino oil on 5K changes, whcih screw with it when synthetic is more expensive??



THAT'S why none if these high mileage trucks have used synthetic. It has NOTHING to do with the oil (other than maybe cost), and EVERYTHING to do with the owner, his personality, and how he uses the truck.



I know that many owner/operators of Class 8s have but the bullet and switched to a synthetic and bypass on their big tractors. Yes, it might cost them $400-$700 to do it, but the results they get keep them doing it once they have converted.



I personally think that synthetic AND dino oil could both be run on a longer drain than DC recommends (agreeing with Gary again? please help me. . I am sick). I also think that greatly extended drains are possible with a bypass system.



IMHO, a synthetic is easily a better oil as far was what oil is supposed to do-- protect an engine. The arguments against syn are always if the cost is justified or if we need the extra protection in an engine that will last forever even on dino.



It's not for everyone, and it's often not even a better value.



I would think that a synethic would be more appropriate for extended drains with a bypass setup because they are less dependent upon additives, so there's less to be depleted over time.



Hohn

 

[Texas Diesel]

Hohn, what you said makes a lot of sense, very few start-stops on OTR rigs.



I still ponder this question myself, I have synthetic oil everywhere except the engine. I just cant get over the cost and I am not comfortable with extended drains



One question for you:



The OTR trucks used extended drain intervals with dino oil for decades, what effect did switching to synthetics have on their established drain intervals? Any ideas?

 

[RustyJC]

For me, it comes back to this:



1. The Cummins will go to at least 500,000 miles with Delo 400 (I'm being intentionally pessimistic - I really think it will go to 1,000,000)



2. I drive 8,000 miles a year



3. Therefore, it will be 500,000/8,000, or 62. 5 years before the truck requires an overhaul.



4. I am 55 years old.



5. I will be 55 + 62. 5, or 117. 5 years old when the truck requires an overhaul.



6. I really don't think it will matter to me at that point!



Rusty

 

[Hohn]

My only real knowledge of this comes from my stepdad, a former diesel mechanic and now an OTR driver for Tyson foods.



Large fleets don't use synthetic often because they don't care ultimately how long the truck will last. They LEASE their trucks, and maintenance is part of the contract. The contractor naturally uses a lower cost oil to save money. If these trucks will run just fine with dino throughout the lease period, so they never have the trucks long enough to where synthetic would benfit them much. Many OTR guys still use bypass and analysis to determine drain interval-- the bean counters bought off on this.



It makes sense too. In a CTD ram, you can almost do a whole change for the cost of analysis, so why bother if you are running dino.



Not so with an OTR where a change can run $70 or more for just the oil. Analysis can reap benefits here, and it's more cost-effective.



As for synthetic, the only time you really see it is with owner/operators who OWN their trucks and want to keep them alive as long as possible. The cost savings of being able to almost DOUBLE your time to overhaul is a huge help to the little guys (O/O).



So, when you add fuel savings in with lower maintenance, it makes more economic sense to run the synthetic with a bypass.



My stepdad says when he was a mechanic you could ALWAYS tell the engines that had been run on synthetic (he didn't get many). The internals were very clean and highly polished-- almost mirror-like. Even the rod bearings were polished and had no scoring or gouges.



He's a big believer in synthetics based on his experience. Last time I went to visit, their '02 PSD was getting a change with Rotella synthetic. only had 2800 miles on it. I guess a PSD doesn't need break in-- (weaker internals)



I don't badmouth their PSD because, well, they are family and all. They would have got the cummins if it came in a Crew Cab.



WHEN IS DODGE GOING TO WAKE UP AND MAKE A REAL CREWCAB?? Don't they realize how many times that this is the ONLY, repeat ONLY reason someone buys a Ford over a Dodge??????



If *I* ran DC, things would be very different indeed... .



HOHN