Synthetic Diesel Oil

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MikeT

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I'm thinking I'm opening a can of worms here, but I've been waffelling about using synthetic oil in my Cummins. I'm due for an oil change and am wondering if I can get double the miles from synthetic as I get from Dino. Syn is running about double the price of Dino for a gallon at Wally. If nothing else I'd rather go 10k instead of the 5k schedule I'm on now. Have Syn in all the family gas engines and have had good experience with it. Use Mobil 1 in all of them. What do you guys think?

Thanks, Mike
 

Fuel35 67

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You changing the oil at such early intervals is wasting time, oil and money. You should be changing at 12-15 depending on the oil analysis results.
 
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MikeT

MikeT

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Got a chance to check with the shop that changes my oil yesterday. The guys said "Dyno oil or synthetic doesn't matter 5k miles and change it" dyno it is at about 1/2 the price of synthetic.

My Cummins is a 5.9 and 5k miles for oil change is what they recommend I believe.

Thanks for the replies guys.

Mike
 

Fuel35 67

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You are wasting money. But it’s your truck, your money. Just trying to save ya a few bucks.
 

Gr8bawana

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You are wasting money. But it’s your truck, your money. Just trying to save ya a few bucks.
The guy is already wasting $$ by paying to have the oil changed so he's just gonna waste extra $$.
That being said, I don't think anyone ever hurt their engine by having oil that's "too" clean.
 

Fuel35 67

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So true. But if ya want it clean, use a bypass system.
 
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MikeT

MikeT

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Thanks guys for the comments. I'll continue to be using the regular Dyno oil rather than synthetic. The reason I have my oil changed is that I don't have the facilities to change it myself and at my age (77) I'm not willing to do a ton of manual labor to get it done. I buy my oil at Wally so I save several bucks on that. They change oil, oil filter, check/change the air filter, rotate tires and this change will check the brakes for me. To me it's worth the money to not have to do that myself. On average I put on about 7 to 8 thousand miles a year on the truck.

Mike
 

Fuel35 67

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Then changing the oil once a year will suffice. And at your age, there’s nothing wrong with paying someone to do what is needs to be done.
 

crash68

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My Cummins is a 5.9 and 5k miles for oil change is what they recommend I believe.
Try the recommended oil change interval is 15000 miles or 7500 miles if you work the engine hard.
Oil change depends on how you use it, if you put a lot of highway drive miles on then 5K is a waste of money. Unless you idle the truck for hours on end goto a synthetic and no less than 7500 miles(more like 10 K) or 1 year whichever come first.
Before you go on about how black the oil is, you know how many CTDs(or diesels in general) pushing over 500K miles oil looks black like that for probably the entire 15K-20K mile oil change intervals.
 

HDGoose

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The guy is already wasting $$ by paying to have the oil changed so he's just gonna waste extra $$.
That being said, I don't think anyone ever hurt their engine by having oil that's "too" clean.


PepBoys changed the oil in my truck for $20 more than the oil and filter cost me. And they used the Shell Rotella diesel oil I use.
 

smiley

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Twice the miles = twice the contamination. Synthetic does nothing to change that.

Cummins specifically does not endorse extended oil change intervals because of synthetic.
It doesn’t breakdown like conventional so you don’t have to worry about it getting thin then really thick and causing sludge. It is superior in pretty much every way. If you filter it well it will last until all the detergent is gone.
 

Gr8bawana

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It doesn’t breakdown like conventional so you don’t have to worry about it getting thin then really thick and causing sludge. It is superior in pretty much every way. If you filter it well it will last until all the detergent is gone.
It may not break down but it still gets dirty like any other oil. The owner's manual makes no mention of longer oil change intervals if using synthetic oil.
 

Fuel35 67

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Cummins does endorse the use of synthetic oil.

Copied the statement


Valvoline Premium Blue Extreme Full Synthetic Engine Oil is exclusively endorsed and recommended by Cummins, meeting API CJ-4 specifications, including Cummins CES 20081.


Synthetic oil doesn’t break down when hot like Dino oil, think about it. Your turbo will thank you for using synthetic.

If you want to run extended oil changes, use a bypass filter system. Amsoil has a BEAP 100 that’s good for 70k. I suggest getting an oil analysis if you go this route.
 

Gr8bawana

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This is directly from the owners manual. It say "you may use synthetic oil" if it meets spec. Nowhere is there any endorsement or recommendation to use synthetic.
There is nothing wrong with using synthetic oil but it is not needed and an unnecessary expense.

Lubricants which do not have both the engine oil certification mark and the correct SAE viscosity grade number should not be used. Synthetic Engine Oils You may use synthetic engine oils provided the recommended oil quality requirements are met, and the recommended maintenance intervals for oil and filter changes are followed. Synthetic engine oils which do not have both the engine oil certification mark and the correct SAE viscosity grade number should not be used.
 

Gr8bawana

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Show us where in the owner's manual it is endorsed and recommended.
 

Fuel35 67

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Even if it’s not in the owners manual, you have been proved wrong about Cummins not endorsing synthetic oil.
 
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