Considering Switching to Full Synthetic Oil

rayporter

WKR
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Jul 3, 2014
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arkansas or ohio
i had a 2001 ram Cummins that had 199,000 mi on it the last time i sent in an oil sample.

i had went 10,000 i on that particular oil change. the report came back to try for 12500 mi next time.

but it is the opposite on my 2017 Cummins ram. the computer [or i suspect the milage monitor] says to change at 10,000 every time. no matter how i drive or what i pull. any interval over 7000 mi and Blackstone says i have wear. a 5000mi interval is about right. it has 90,000 on the engine now.
 
Joined
Oct 24, 2015
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W. Wa
The reason for frequent oil changes isn't necessarily due to the oil or additives degrading - its the filter. Engineers were smart enough to build in a pressure-based bypass into the filtration system. Once it gets too hard to push oil through the filter(due to it getting full) it starts bypassing so the engine isn't starved of oil. The upside is the engine doesn't grenade because it isn't getting lubrication. The downside is there's no filter to keep the nasties out of your engine.

So, even with a full synthetic that claims it can go 10-15-25k you're still changing oil at 5-6k. Hell, the oil change interval on the last 2 trucks I owned was 10k and I still change it at 5-6k.

Its like cheap sleeping bag ratings. It looks good on the box, but never translates to real life.
 
Joined
Feb 23, 2023
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I went full synthetic Mobil 1 when I bought my 98 Z71. I've run it for over 470,000 miles, it's still going strong. I ran it in my 01 Vette, now in my 15 Audi A7. I don't have to change it as often.
 

Wrongside

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Jun 3, 2012
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AB
Guys use cases will all differ at least a little. I buy good condition used or new vehicles, and then drive them into the ground. Anymore we only own Toyotas for long term reliability and durability. And we get every last Mennonite inch out of them.

8000 kilometer oil change intervals. Full synthetic 5W30 or 0W20 Pennzoil Ultra Plat. OEM or WIX filters. (Viscosity depending on the age of vehicle/Toyota spec).

As a few guys have said- Oil is cheap, engines are expensive.
 

coiloil37

Lil-Rokslider
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Jul 24, 2013
Messages
193
Location
Oz
I hope you guys with the 6.7 Cummins are running the Donaldson DBL7349 oil filter. There isn’t a better full flow oil filter for that engine.

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The factory fleetguard is a 40 micron filter, the Donaldson is 15. The Donaldson is also cheaper then the mopar painted fleetguard.
 

Sled

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Jun 11, 2018
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Utah
This is one reason to not push the oil change intervals if you're running an ecoboost

 

CorbLand

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Mar 16, 2016
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NAPA here does a 50% off on oil filters once to twice a year. I buy enough to have three on hand for each vehicle. Generally its coupled with their branded (produced by Valvoline) full synthetic oil on sale for ~4 buck a quart.

I change the oil on my wifes car and my pickup every 5K. Usually equates to about 2/3 changes on my wife car per year and about 2 on my pickup. About 25 bucks a change at 5 changes a year...125 bucks. Going to 7500 would change that to ~3 changes a year. I think I will spend the extra 50 bucks.
 
Last edited:
Joined
Dec 27, 2015
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966
This is one reason to not push the oil change intervals if you're running an ecoboost

I had the coolant and oil lines replaced when I had my 3.5 Eco manifolds done at 163k.
The tubes and filters were much cleaner than I or the mechanic expected.
Maybe towing or hot environment would have a different result.
I loosely stick to the display OCI.
Generally 2X/yr.
 

Backyard

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Jan 24, 2014
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Minnesnowta
Go on the Amsoil website. They test oil.

Of course they do! And if it’s their product that they’re testing, it always tests out perfectly. And opposite.
I think if I really needed something tested I would choose an independent company to do the testing.


Sent from my iPhone using Tapatalk
 
Joined
Nov 22, 2023
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Whichever brand you go with, just make sure you read your owner's manual to make sure it is the appropriate type. Not all synthetic oils of the same viscosity are adequate for every vehicle. I have a Jeep Gladiator EcoDiesel that uses 5w-40 of a specific requirement ("MS-12991"). Only a few brands meet this, as per the label on the back of the container. I need nine quarts of this stuff and it's not cheap, but I get in on Amazon when it goes on sale. After picking up an OEM oil filter and investing in a couple decent quality tools to do the job myself, I cut my oil change costs in half. NTM I can go 7K-10K in between changes with synthetic.
 
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