Syn. vs. Dino - Engine Cleanliness - simple question

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Jan 6, 2005
North Alabama
In a little over a year that I've spent on BITOG, I've come to the realization that synthetic oils are very use-specific, & not necessary for most passenger cars & light trucks, except as specified by the vehicle manufacturer. it, or is it not true, that in a properly maintained engine, synthetic oil will keep an engine's internal parts considerably cleaner, over say 100k+ miles, than a dino oil with equal specifications?
Personly I think they will since they have a more uniform Molecule size and would be less prone to burning off and coking. Which would result in fewer deposits.
Perhaps. A toyota 3.0L V6 will be substantially cleaner with PAO than with dino. Just depends on how tough the specific engine design is on oil.
One of the attributes of synthetic oil is greater resistance to oxidation than conventional oil. Much of the crud you see inside an older engine is the products of oxidation of the oil. Look at this chart of base oil properties from Chevron and check the rows for Oxidation Life and Deposit/Sludge Control Note that the Asian (Korean?) Group III oil isn't that special. Ken
I saw a good point made in a thread awhile back: We often see older engines run on dino with some varnish buildup. The poster said that that dino buildup likely came from the dino used in the engine 10 years ago, and the current oil isn't varnishing anymore. That made sense to me, but I really don't know if it's true or not.
I would think that 23 oxygen stability for the Asia VHVI 8cST is almost for certain a misprint. Their light-neutral-oil is 35 and the medium <i>should</i> be around that.
I don't think there is going to be a difference with todays oils.. Especially if you boost the already oxidatively stable GF4 oils with LC. Any oil can coke or sludge if there is a mechanical problem. PAO is not Carbon deposit kryptonite. Certain additves are close to it.
Saab and VW engines less than three years old show plenty of varnish with dino oils. You never get that with Redline.
With the old Grp I oils (~ pre 1998), there was a big difference in engine cleanliness compared to synthetics -- unless the OCI was kept to very short intervals. With the newer oils (Grp II), even at medium drain intervals they should be very close to synthetics in engine cleanness.
With saab, though, it's the result of an inefficient PCV system. However, I still agree...dinos still varnish...
If the question is: Will walmart supertech dino oil, changed every 6K miles keep my engine as clean as mobil1 changed every 6K miles, then the answer would be, NO... Mobil1 would certainly keep it cleaner. However if the question is: Will walmart supertech dino oil changed every 3K miles keep my engine as clean as mobil1 changed every 6K miles, then my answer is: I dont know. My guess is, yes, the dino oil, changed twice as frequently would keep the engine just as clean as the synthetic run twice as long. My engine has never seen synthetic (Other than Motorcraft blend and castrol blend). It's only got 45K on it, but looking inside the valve cover it appears as clean and varnish free as the day i bought it. My previous car had over 200K on it when i sold it and also only saw dino in its life, and while i would assume it had some varnish or something after than many miles, it burned no oil and the orig PVC valve was still working fine. It was a 4 valve SOHC though. Had it been a turbo or 16 valve, my story may not have been so successful [Wink]
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