Oil Change Interval ?

[08HoeCD]

If nothing else, I appreciate the OP sharing findings. It's refreshing to see actual scientific data and test results as opposed to the typical 'well, I've always used X brand of oil and changed it every X miles, and I've never had a problem.'

 

[donjetman]

Remember me? I started this thread here last April. Go to my original post here to refresh your memory

Todays post has the results of UOA(used oil analysis) #2. Again, the lab is Oil Analyzers Inc(OAI) or Polaris Laboratories. See picture below.

The vehicle is a 07 Yukon Denali w/aluminum L92 6.2L w/147,000 miles now. We used the same oil this time as last time, Mobil Delvac 1 ESP 5-40w. Here's a link about the oil: https://www.mobil.com/English-US/Commercial-Vehicle-Lube/pds/GLXXMobil-Delvac-1-ESP-5W40

The Oil Change Indicator said "50% Remaining" when I took this sample. This time the oil has 6163 miles and 119 hrs on it, which means I averaged 54+ mph. We did two 2000 mile hwy trips and the rest was local driving. We averaged 16.1 mpg, burnt 382 gallons of 89 octane Mid-grade unleaded. My catch can caught 1 oz of thin gasoline like liquid(see pic), not thick like oil. I did not add any makeup oil. Its down about 1/3rd of a qt from the full mark. When we bought it last Oct it burned and leaked more than 1 oz of oil per 100 miles. Not no more! (Read all my threads)

The reults are just as I thought they would be, GOOD! There is plenty of life left in the oil. I plan to leave the oil and the full flow filter in place for another 2000+ mile hwy trip I'll be doing soon. Then I plan to change the oil and full flow filter with the same. I might send in another sample then too.

I'm not worried about the "oxidation" because the viscosity hasn't changed. New it's 13.8, the report says it's 13.9. The lab doesn't know what this oils oxidation # is when new, so they can't give me an accurate recommendation about it. They want ME to send them a virgin sample on my nickel so as to educate them. I DON'T THINK SO! They don't have a BASELINE REFERENCE on this oil. They flagged it "RED"(severe) and they don't even know what it is when new. I gave them some grief about that last time and I will again.

What do yaw think again?

 

[thompsoj22]

Your test is accurate and valid reason to believe that factory oil change intervals can be followed or extended without harm to the components that require lubricity to prevent wear. But i do think that combustion by products/gases and the chemical compounds they create, the oxidation that results in reaction to metals is also just as important if not more so. Are you sure your not riding the razors edge in relation to pitting/corroding as the engine cools and electrolisis has it's way as the engine sits "static"with water vapors present, especially in the winter. I know you are a good mech, but i think your oil will end up corrosive long before it's lubricating qualities are gone. Im rambling! That oil looks dirty as crap! lol! im headed to wallmart and buying another 5qt's of mobil one 5/30 for $22! I followed your thread when you worked the bugs out of the vehicle, i know money isnt the reason you are testing the limits of oil. are you sure you feel good pulling the grades in Colo at 3500 rpm for 25 miles with oil that has 15k miles on it?

 

[mountie]

combustion by products/gases and the chemical compounds they create, the oxidation that results in reaction to metals is also just as important if not more so. Are you sure your not riding the razors edge in relation to pitting/corroding as the engine cools and electrolisis has it's way as the engine sits "static"with water vapors present,

I have heard same talk from my friend that has dyno tuned motorcycles for decades....... My friends that build race engines don't care about that ...race engines get refreshed.
"Long-lasting oil" ?? / then only change filter a couple times????? Nope.
Change oil at suggested intervals !!!!!!

 

[donjetman]

Again look at the first sentence of post #1. I appreciate those that appreciate what I'm doing.

Based on these 2 UOA reports for the Yukon, I think 8K to 9K miles is OK for this oil for the way we operate the vehicle. When I say OK, I mean I'm not changing it too early, or too late. If I'm wrong, hopefully we'll all learn something.

Below is a picture of all 10 UOA reports for my current daily driver, 07 FJ Cruiser, w/240hp 4.0L v6. It gets 20+ mpg doing 100% local driving. So its much easier on oil than the Yukon. The oil brand was Amsoil for the first 6 reports. You can see how high the "oxidation" levels were w/Amsoil and it didn't hurt a thing. The FJ now has 195k miles on it and doesn't burn or leak any oil. Like the Yukon, I run a engine oil bypass filtration system on it. Toyota says to run Super unleaded. It has seen nothing but regular unleaded. I'm getting away w/ mid-grade unleaded in the Yukon. The FJ has the same oil in it as the Yukon right now, Mobil Delvac 1 ESP 5-40w, and I will do a UOA on it before the year is out. The oil will have 10-12K miles on it. That will be interesting to see how it held up compared to the Yukon.

TBN, total base #, is "the additive package level" in the oil. The better the oil, it usually cost more, the more robust the additive package, and the longer the oil will last. Also, the better oil start out with a higher TBN#. This oil starts out new with a TBN# of 12. WalMart full synthetic, see #7 below, starts out at 10. And its not just the quanity of the additive pkg, its the quality too. I like to change the oil when the TBN gets down between 2 and 3. I've used Blackstone and OAI labs. OAI is more conservative and will flag the TBN# sooner, when it gets below 3, not Blackstone. If anyone uses Blackstone Lab, make sure to pay the extra $$ for TBN# etc.

 

[gooffeyguy]

Just curious, I've never had my oil analyzed, about how much does it cost?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[mountie]

Your numbers are good........

But, since changing my oil is one of the cheapest chores to do, I am not going to stretch a few miles.

 

[donjetman]

Just curious, I've never had my oil analyzed, about how much does it cost?

Retail thru the Amsoil website = $34
I pay $20/yr to be a preferred customer so my discounted price is $28.35 thru the Amsoil website.
I make an order online and 1 or 2 days later its at my house. Shipping is free if I order more than $75 worth of stuff.

OAI website: http://oaitesting.com/
Amsoil retail: https://www.amsoil.com/shop/by-product/other-products/oil-analysis-services/

 

[gooffeyguy]

So about the cost of an oil change, maybe a bit less?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[HiHoeSilver]

Just curious, I've never had my oil analyzed, about how much does it cost?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

Retail thru the Amsoil website = $34
I pay $20/yr to be a preferred customer so my discounted price is $28.35 thru the Amsoil website.
I make an order online and 1 or 2 days later its at my house. Shipping is free if I order more than $75 worth of stuff.

OAI website: http://oaitesting.com/
Amsoil retail: https://www.amsoil.com/shop/by-product/other-products/oil-analysis-services/

I use Blackstone Labs. Its $28. Plus $10 for the TBN which is optional.

https://www.blackstone-labs.com/?se...abs.net/Bstone/(S(x2velq55fzpk1355pmwtx555))/