Synthetic, still make sense?

[02supercrew]

My '06 CTD has a MFG'er reccomended OCI of 7500 miles for towing, and 15000 miles for light duty. No mention of synthetic oils what so ever, other than breakin should be with a conventional.

With that said, I'm going to go out on a limb and ask the following:

Why would one want to use a synthetic in this case rather than a HDEO conventional with these kinds of OCI's, other than for a warm and fuzzy feeling. If the MFG'er says I can take regular house brand oil (with proper ratings) out to 15K on the same filter, why would I wan't to use a synthetic?

 

[Pablo]

I think the main thing here is sump capacity, but if you go 15K miles on conventional oil, perhaps a UOA would be in order.

The reason for synthetic would be not only doing 15K with ease, but easily going beyond that year around while cranking a full oil pan at -5° F, cruising all day at 105°F, with less wear and less piston build up. Sure conventional may do that barely, synthetic oil just does it better and longer.

 

[LargeCarManX2]

I take it that it's a Dodge Diesel Pickup?

Take a look at the light duty qualifications.....

Most, if not 90% of owners don't meet these guidelines.
Most, if not 90% of Amsoil or Mobil users don't meet this synthetic oil 15K vs. 25K or 35K guideline.

The only way to really tell is to run your own tests. Try a 8K test and UOA that oil with a particle count. Then look at the results. If your oil is still good to go UOA at 12K and look at the results.

We have seen these engines UOA's with synthetics that could easily go 15 or 20K. The trick is to do the full 25K with Filter to make synthetics payoff. The gap is closing and your question/s are valid.

I don't suscribe to OEM or Aftermarket oils guidelines on OCI's.

 

[Steve S]

Unless you live in a freezing climate there isn't any reason to run syn oil unless it is recommended by the engine manufacturer. Get a pyrometer to measure the exhaust gas temperature and don't overheat the turbo and don't shut the engine down till 300 degrees.And your engine will have all the protection it needs.

 

[1sttruck]

The 7500k miles change interval is not just for towing, it's also for lots of stop and go driving, idling, etc.
This means that unless you do mainly highway driving you need a 7500 OCI for warranty, regardless of what oil you use. A 5w40 HDEO works better for lots of cold starts.

 

[1040 WreckerMan]

Those 6BTA5.9's are very easy on oil and can run longer OCI's on just about anything. We have some 4 and 6BTA's that run mostly highway miles and they are around 18k OCI's and they do fine. Most people drive the trucks as grocery getters and daily drivers and thus qualify as severe duty, imo. Driving them back and forth to Wally World is harder on them than towing constantly on the highway.

If you want long OCI's then synthetic is the way to go. If you want the comfort of knowing that the oil in the crankcase will protect if you do occasionally exceed the limitations of conventional oil then synthetic is the way to go. In most cases plain old dino HDEO will work fine. Synthetic oils like Schaeffers 5w40, Valvo PBE and Rotella 5w40 are great oils for the money and work much better in cold temps.

 

[BMWR1150GS]

CAT 3126B, turbo, air to air intercooled, pushing a 27,000 lb. motor home with a rather warm engine bay (rear engine RVs are noted for running a bit warm due to poor air flow over the radiator. Those of you with R-E RVs, check hoses and belts routinely...they deteriorate more quickly than on front engine layouts).

I use Delvac 15w-40 1300 exclusively. At less than $9.00/gallon (5 gallons are needed), I think this oil is a bargain. Change intervals are about 6 months rather than mileage dependant.

Synthetics tolerate hear better and typically have higher TBNs thereby keeping the additive package in better shape. Once an engine is bedded in, synthetics are my choice due to extra protection and extended drain intervals.

If you routinely change oil at short intervals (less than 10,000 miles) and don’t short haul the engine, dino oils are a reasonable choice.

But remember, short OCIs exhaust oil reserves more quickly. Synthetics make sense in that regard.

 

[BMWR1150GS]

Quote:

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Why would one want to use a synthetic in this case rather than a HDEO conventional with these kinds of OCI's, other than for a warm and fuzzy feeling. If the MFG'er says I can take regular house brand oil (with proper ratings) out to 15K on the same filter, why would I wan't to use a synthetic?

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Better Noacks
Better temperature tolerance
Better pour point
Better oxidation control
Better soot handling capacity
Higher TBN
Longer OCIs
Better resistance to shear

Just my opinion…

 

[1040 WreckerMan]

The CAT 3126 and C7 engines are very hard on oil. Just as hard as the Navistar T444E/VT365/VT265 engines are in fact. A synthetic oil is of much better value in this case because of the loads imposed on the oil from the HEUI fuel system. The Cummins 6BTA is either a Bosch VE rotary distributor pump, VP44 rotary pump, P7100 inline pump or Bosch CP3 common rail fuel system. These only use engine for for lube purposes. In addition the 6B engine family (including the 4B) have fairly large sized main and rod bearing surfaces which help reduce the load on the oil.

Certainly the points brought up about temperature tolerance and pour point is important, but for most people they are not needed in diesel applications. The Cummins is unusually easy on oil making synthetic all that more cost prohibitive. If running synthetic oil makes ya feel warm and fuzzy then great, go for it. I change my ATF and gear oils much to soon for that very reason

We have several C7 CAT's at work that run standby service. Get started cold, run the pis out of them (mostly in town) and idle for extended peroids of time and we don't have any oil related trouble with them. I think we are running them 12K OCI's on dino 15w40 (whatever is on sale when it gets ordered.) and we have yet to see evidence of this routine harming the CATs in any way.

 

[02supercrew]

Thanks for all of the replies.

Yes I agree that my CTD is definately easier on my oil that the 7.3L PSD I used to have.

The reason that I posted this thread was because of what my manual says, and a lot of the conventional HDEO's that are from the 5.9L seem to show a boat load of TBN left in the oil at the 7500 mi mark. I can see why the manual reads like it does.

When I see other motors not even comming close to making this suggestion as far as a 15K OCI on regular dino, maybe my statement should have said, "Synthetics still make sense in a CTD"?

 

[SteveD2]

Other than I run a bypass, my Rotella 15w40 looked good at 10k...I am changing bypass setups, so I will need to do it again, but I will most likely stretch out to 15k intervals unless I plan on some towing or actually working the truck.

steved

 

[Steve S]

Quote:

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Quote:

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Why would one want to use a synthetic in this case rather than a HDEO conventional with these kinds of OCI's, other than for a warm and fuzzy feeling. If the MFG'er says I can take regular house brand oil (with proper ratings) out to 15K on the same filter, why would I wan't to use a synthetic?

---

Better Noacks
Better temperature tolerance
Better pour point
Better oxidation control
Better soot handling capacity
Higher TBN
Longer OCIs
Better resistance to shear

Just my opinion…

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And?

 

[buster]

Quote:

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Unless you live in a freezing climate there isn't any reason to run syn oil unless it is recommended by the engine manufacturer.

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Correct. Synthetics are really for extreme temps and extended drains. If you haven't already noticed, conventional oils and synthetics share the same additive packages most of the time. The main difference is the base oil and AO's. People that run synthetics for 3k-5k miles are really wasting oil and their money. Now that we have oils that meet the demanding API SM spec, you can't go wrong with any oil out there.

 

[1sttruck]

My manual calls for a CI-4, the new stuff is CJ-4. I notice that a lot of SM oils are also rated A1/B1, but not nearly as many are rated A5/B5, which seems to be a rating for higer performance and extended drains.

As I recall my manual also states not to use synthetic during break in, which can take as long 20k miles if you don't tow. Seems like synthetic results in less wear, regardless of what a UOA might indicate. Whether some unknown amount of lower wear is important will depend upon how long someone plans on keeping a vehicle. Some of Dodge diesels have hit over 1 million miles, but that seems to be mainly with vehicles having mainly highway miles with a lower number of cold starts. Average engine life is 350k miles in a medium duty application. So, what does it take to get to say 500k miles or more, if use includes lots of cold starts ? Maybe a synthteic oil will help ?

 

[bmwtechguy]

Schaeffers 7000 blend 15W-40, or 9000 5W-40 full syn. Both excellent oils. Great wear protection without the overinflated price of some more well-known brands. Donaldson Synteq or Amsoil EaO full flow. Why not add a bypass filter of your choice too and go all the way to 1 million miles on your engine? Don't wait until you're already over 200k miles to install a bypass (like I did- real smart, huh?)

 

[mdocod]

My step-dad runs synthetic in his 1 ton dodge cummins. It's usually loaded to about 12,000lbs. And routinely pulls a trailer weighing ~8000lbs. Gets run hard 6 days a week. Lots of miles, lots of stop-n-go, lots of cold-start-n-goes. He changes it every 5k "just to be safe." I don't blame him, It's a business vehicle and needs to last a long time to pay off.

 

[Strjock81]

Schaeffer's 5w-40 has improved the MPG in my 04.5 CTD, I am running 7500 mile intervals, since I mostly use it to pull a trailer.