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Discussion Starter · #1 ·
Where to begin. We own an 08 Acadia SLT and from day one I have been changing the oil and filter. I have my oil sent off for analysis when ever I change it. Well from the advice of the individual that I have been dealing with for the past 6 years or more and he has been doing oil analysis for over 25 years, I changed out the oil on the Acadia to his recommendations. Basically I changed the oil and filter out at the first 500 miles, then just changed out the oil when I put 1,500 more miles on the Acadia, then went 3,000 more miles and changed out the oil and filter. This was at 5,000 miles on the Acadia. From there it was a fresh oil filter and oil, ran that for 5k miles and then had the oil analyzed. Turned out the oil was out of spec and seriously fuel diluted. Basically the high fuel dilution killed the oil. So I changed the oil again per the labs recommendations and went another 5k miles which put it at a total 15k miles on the vehicle. This time the oil was again out of spec and still had high oil dilution. So now I'm on the third long oil drain phase and going to see what happens at the next 5k miles. The individual that has been reading my analysis can't figure out what is going on. Something inside the engine isn't working properly, and from what he can tell it seems to be an issue with the computer and how it is set to run the engine, basically running it to rich. Now I'm running a really high quality oil, not your basic off the shelf Pennzoil, Quaker State or Valvoline. What I'm being told is the oil I'm running is taking a beating and if it wasn't for it specifically then regular oil would have been shot sooner. I'm spending money on quality oil. It is something I do since it is my hobby and interest, that is why I do oil analysis on my vehicles. Again it is my choice to run a premium engine oil. I'm not saying that everyone else has too. It is just what I like to do. Some have a hobby of sports, fishing, golf, hunting, boating, mine is oil analysis and using quality oils to see how my engines are holding up and if any problems arise like they are now with a brand new vehicle. My 02 Silverado is running great and I have been able to go to 15k mile oil changes before the oil is to the point of needing changed, which runs about a once a year oil change. I would think the Acadia would be able to do the same but for some reason it isn't.

I'm wondering if the engine beating up the oil like this has any relation to the other issues like the cams going bad, due to the programing of the ECM. The fuel dilute got worse this second time when I had my oil analized. It just so happened that we had the transmission TSB done at the same time as the last oil change. So with the new program and shift patterns is there a connection to the high fuel dilution? Terry who reads the oil analysis is concerned. He is familiar with this engine and there isn't any problems with it in the CTS and since I'm one of the few that send in an analysis from an Acadia he doesn't have much info to go on for it in our application. He just doesn't understand why it is running in this condition to trash the oil like it has. He has stated time and time again, it isn't the oils fault, the something with the running condition of the engine is beating the oil to death.

Is the fact that the oil isn't lasting long due to the engine running parameters causing other issues? The oil should be lasting longer than 5k miles, especially the oil I'm using. I sure wish I could win the lottery so that I could afford to have several other Acadia owners oil analyzed to see how things are inside their 3.6. If a full synthetic is getting beat up then regular oil doesn't stand a chance. Heck the oil I'm using is shearing down from a 30 weigh oil to a 20 weight, that shouldn't be happening in just 5k miles. Terry is seeing the oil I'm using last well over 10k miles in other applications with no problems and everything staying with in specifications.

Just wanted to share this with everyone. To me it brings up a question to some extent. Maybe our Acadia is that one in a million that for some reason has an issue with the engine run program and hopefully everyone one else is ok.
 

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Hmmm. How has your gas mileage been?
 

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Just wondering if the oil life indicator in the DIC showed the oil degrading like that?
 

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likely not. the DIC oil life indicator is soley based on historical oil degradation that GMC pre-calculated based on various types of driving. it does not actually sense how your real oil is doing... only how it "should" be doing based on your driving style and conditions.
 

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Discussion Starter · #5 ·
loach said:
Hmmm. How has your gas mileage been?
Our gas mileage has been on average according to the DIC around 19.9,mostly city, country road driving.

The oil life monitor has never gone off because I reset it every time I changed the oil. It has been around 50% life left when I changed the oil the last time with 5k miles on the oil.
 

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You may want to have your engine checked at a dealer. I've had my oil checked by Blackstone Labs (one of the majors in the field) at 4 k miles (thats all I do on mineral oil) and fuel dilution was <0.5% (thats their bottom reporting level) where the allowable is 2%. Thats typical of all four of my cars. You may have an area of a ring not sealing well or a bad injector pattern that need to be remedied. What percent dilution are they actually reporting?
 

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Rat407 said:
Turned out the oil was out of spec and seriously fuel diluted. Basically the high fuel dilution killed the oil. So I changed the oil again per the labs recommendations and went another 5k miles which put it at a total 15k miles on the vehicle. This time the oil was again out of spec and still had high oil dilution.
What were the actual readings and for what parameters was the oil out of spec? What does kill the oil mean quantitatively? How did the other test parameters for the oil look? I was told by Blackstone labs that high fuel dilution readings can sometimes show up in oil samples that were taken from not fully hot oil. There is always some fuel dilution in oil that is not fully hot. That 's why short trips are so hard on oil life.
 

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Discussion Starter · #8 ·
GerryL said:
You may want to have your engine checked at a dealer. I've had my oil checked by Blackstone Labs (one of the majors in the field) at 4 k miles (thats all I do on mineral oil) and fuel dilution was <0.5% (thats their bottom reporting level) where the allowable is 2%. Thats typical of all four of my cars. You may have an area of a ring not sealing well or a bad injector pattern that need to be remedied. What percent dilution are they actually reporting?
our fuel was at 1.6% which is way high. Also the high fuel pushed up other readings from the last report. Lead was at 22 so the bearings are taking a beating, like I said it sheared to a 20w which isn't good either, flash point which should be above 400 was down to 285 and oxidation which shouldn't be past 20 was at 159. In other words the oil lost it's ability to protect the engine and wear was starting to really take place.

The oil sample was taken after a nice long interstate run. Matter of fact the oil sample tube I used to pull it from the dipstick area was super soft so the engine was up to temp and for a few miles of driving, that should have taken care of any fuel dilute from running cold.
 

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I did a 10K mile interval last time (I wrote down the exact numbers but it's out in the car right now). The oil monitor said I had quite a bit of life left. I did pull a sample and put it in a mason jar for testing but didn't know where to send it. The other question is this is the oil the dealer put in for my free oil change, so I don't know what it was to start with.

If you let me know where to send it, I'll be glad to send it in and see what we get.
 

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I will send mine in also. It is about to get changed soon, so let us know. :thumb:
 

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Discussion Starter · #11 ·
Schram said:
I will send mine in also. It is about to get changed soon, so let us know. :thumb:
I use http://www.dysonanalysis.com/ He goes above and beyond anyone else I have use. He actually sends the information in on a PDF file and with that he sends an explanation on an mp3 file so you can listen to him explain exactly what is on the PDF file. You just listen and follow along. He covers everything that an oil analysis can give you.

You can also use http://www.blackstone-labs.com/free_test_kit.html Blackstone is good as well but just send you back a written statement with the report. Also you don't get the entire readings, to get the TBN, which is the total base number and what tells you how much of the additive package you have left in the oil. The additive package is what fights all the acids and such in the oil to keep it in spec. If you want the TBN from Blackstone it is an extra $10 I think on top of the regular oil sample cost.

You can always collect a sample of the oil and hold on to it until your oil sample kit comes in the mail. Just get a clean plastic container, like an old peanut butter jar or something similar. You want to collect at least 6 oz or about as much as a half to 3/4 full coffee cup. Better to have a little extra than not enough. So when your ready just make sure the engine is at operating temp, pull the drain plug, let the first couple seconds of oil drain out into the pan and then collect the middle part of what drains out, that way you don't get any of the bottom diry oil or what flows out the hole first that might get contaminated by anything around the drain plug. You get the good mixed up oil that was in the pan.

It cost about $1.90 to send in an oil sample. If you want it to get there faster Priority is about $4.00 There is nothing special, it isn't considered hazzardous. Average turn around time is anywhere from 4 days to two weeks. Depending on the lab and how busy they are and how fast the mail gets the sample to them. Below is a letter on Blackstones web page about sending oil samples in the mail.

Dear Sir or Madam:

The product being sent in our oil sample container is new or used lubricating oil. It is not hazardous, flammable, or toxic. The average flashpoint of used engine oil is 380°F. Used transmission fluid or lube oil has an average flashpoint of 340°F. The minimum flashpoint for all oils we receive is 250°F. The postal regulations for Hazardous Material (DMM 601.10.6) indicate that:

"For air or surface transportation without restriction, if the flashpoint is above 200°F (93°C). Mailable combustible liquids must be properly and securely packaged to prevent leakage."

Our oil analysis kit consists of two HDPE plastic bottles, both with lined screw-on caps to prevent leakage. The white inner bottle (capacity: 120cc) and absorbent material should be placed in the plastic zip-lock bag. This bag and absorbent material not only prevent leakage from the inner bottle, but they also serve as packing material to prevent the inner bottle from being jarred during shipping. Should both the inner bottle and plastic bag leak, the outer bottle will contain any excess oil. The oil must be packaged as we have specified to meet USPS regulations.

In the unlikely event that oil should actually spill from the black mailer, the clean-up procedure (as specified by MSDE Safety sheets for virgin and used oil) is to simply contain the spill and wash contaminated areas with soap and water.

This letter and the accompanying packaging have been approved by the United States Postal Service. If you have any questions about the samples being sent to our laboratory, please contact Patty Buell, USPS Manager of Customer Services, at 260/427-7316. You may also contact Blackstone Laboratories at 260/744-2380.

Sincerely,

Kristin Huff
Vice President
Blackstone Laboratories
 

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Thank you very much. I will send mine in and post so you know if our results are similar. Mine was dealer changed the last time. The DIC says 50% remaining, so it should be comparable.
 

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Rat407 said:
GerryL said:
You may want to have your engine checked at a dealer. I've had my oil checked by Blackstone Labs (one of the majors in the field) at 4 k miles (thats all I do on mineral oil) and fuel dilution was <0.5% (thats their bottom reporting level) where the allowable is 2%. Thats typical of all four of my cars. You may have an area of a ring not sealing well or a bad injector pattern that need to be remedied. What percent dilution are they actually reporting?
our fuel was at 1.6% which is way high. Also the high fuel pushed up other readings from the last report. Lead was at 22 so the bearings are taking a beating, like I said it sheared to a 20w which isn't good either, flash point which should be above 400 was down to 285 and oxidation which shouldn't be past 20 was at 159. In other words the oil lost it's ability to protect the engine and wear was starting to really take place.

The oil sample was taken after a nice long interstate run. Matter of fact the oil sample tube I used to pull it from the dipstick area was super soft so the engine was up to temp and for a few miles of driving, that should have taken care of any fuel dilute from running cold.
As you said, it's not good. Show the dealer your oil analysis and get the engine looked at. Good luck.
 

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I changed the oil again yesterday and sent off two samples to Blackstone. The 1st one was from February with almost 10K miles on the oil (13% remaining by OLM) and almost 8K miles on the oil yesterday (26% remaining by OLM). We'll see what the results are.
 

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I'm surprised at the good MPG with this taking place. I recall a similar issue with the LS1 V8 where one (#7 cylinder springs to mind) would wash out & eventually loose compression.
 

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Rat, what was the labs recommendation you should do with the results not in spec? If you continue to change every 10K using full synthetic, did they say what type of cam wear...etc could be expected after 50,000 or 100,000 miles?
Is the lab able to determine what the dealer should be looking when you take it in......example: Will diagnostics be able to determine if bad fuel injector or compression ratio in a particular cylinder not within specs? Will your dealer have to send out its own sample to confirm your labs findings before performing any investigative work on your engine? You have raised an important issue requiring answers! Please let us know what remedy the dealer/GMC has come up with in this situation. I wonder if GMC has similar complaints on file coupled with solutions? Keep us posted if you will.
Jon
 

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Here are the results of an 8K (26% remaining) and 10K (13% remaining) interval. Sodium is a bit high and they recommend a 4K interval next time.
 

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I like the comment "you have a nice engine that should treat you right". :)
 

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GAR said:
I like the comment "you have a nice engine that should treat you right". :)
maybe it could have been, "you have a nice engine that you should treat right" ;D
 

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Discussion Starter · #20 ·
jseck2 said:
Here are the results of an 8K (26% remaining) and 10K (13% remaining) interval. Sodium is a bit high and they recommend a 4K interval next time.
That silicon is way high, need to check your air filter and all connections to the engine that might pull in air. The sodium can point to antifreeze, notice they put ? where it reads an antifreeze level. I wonder why they did that. No TBN on the second reading. The first reading the TBN was low and basically shot, which means your additive package that protects from acid build up was depleted. Good thing is your fuel dilution is normal where as ours is way high. What type of driving do you do, alot of highway and long runs? Now to see when the other samples come in.
 
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