Synthetic blend or full synthetic?

[Davidd]

was surprised the owners manual For the 2013 Denali suggests sun blend not full synthetic. I just purchased the veh and the dir said 22% oil life remaining but it looked a bit dirty so I changed it w fresh 5/30 full syn. Is this ok and why does book say semi syn?

 

[ccapehartusarmyINF.(ret)]

you can never go wrong by switching to full synthetic the only downside to switch is if you have a really hi mileage engine and switch to full synth you mite expose any bad seals since synth oil molecules are smaller then regular oil molecules
oil life monitors dont physically monitor the life of oil. Thorugh driving habits and an algorythm the pcm calculates an estimate of how good the oil is

 

[Gurrzt]

GM just tried to save money by using a synthetic blend oil, like paying $60k for these vehicles would not cover the cost of full synthetic oil, THANKS GM

I drained the factory oil out of my 2013 Yukon Denali @ 2000 miles and have been using Mobil 1 Extended performance 5W-30 ever since ( have 50k now), my oil change intervals are @ 10k miles, and the oil is still relatively clean.

 

[MichaelSE]

the only downside to switch is if you have a really hi mileage engine and switch to full synth you mite expose any bad seals since synth oil molecules are smaller then regular oil molecules

Do you have a reference for this? Sounds fishy; I mean, 5W30 is 5W30, it'll be the same thickness whether dino oil or synthetic oil.

Anyway, I just switched my Suburban over to Mobil 1 full synthetic at 117k miles. At 119k now and I've experienced no increased leakage. I plan to go 6-8k in between changes. I would certainly recommend going synthetic - at the least, it will save you money because the intervals are further apart.

 

[ccapehartusarmyINF.(ret)]

i said mite i didnt say itll happen to every hi mileage engine you put it in
and actually learned it the gillis automotive textbook in school in a class called "basic engine"
ill explain a little better though
full synthetics are derived from crude through a chemical process and coventional oil is derived through distalation. and becuase of this full synthentic oil has a more consistant molecular structure wich have more uniformed propertys (so all the little molecules look alike ) so its like full synthetic is made in a lab so its more specifically for its purpose and conventional oil from distilled from crude and what you get is what you get some are tall some are small some are fat some are lopsided

 

[ccapehartusarmyINF.(ret)]

Do you have a reference for this? Sounds fishy; I mean, 5W30 is 5W30, it'll be the same thickness whether dino oil or synthetic oil.

Anyway, I just switched my Suburban over to Mobil 1 full synthetic at 117k miles. At 119k now and I've experienced no increased leakage. I plan to go 6-8k in between changes. I would certainly recommend going synthetic - at the least, it will save you money because the intervals are further apart.

so i guess its not so much there smaller then the other its more like there better designed then the other

 

[VICDBOSS]

I used high milage synthetic blend on my 07 burb after it hit 100k. I was losing about a quart and a half every 4K miles before the switch. After I made the switch I noticed I was only losing half that. I sold it at 250k miles. Changed the oil every 4K miles. I think they say the high milage synthetic blend has conditioners in it so it keeps the seals tight.


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[nharkey85]

Most "high mileage" oils have an additive that makes the seals swell up some, therefore possibly stopping/slowing oil leaks/loss. The issue with obviously is swapping to HM oil will cause premature wear to the oil seals.


119k miles I wouldn't consider high mileage. I'm just over 170k, run about 7500 miles between changes, and lose less than half a quart