which synthetic oil do you prefer??

gumpy

Unless you use a very specialised place i'm pretty sure they're using a type of spectrum analysis on the oil... and from what i understand that only gets you the dissolved stuff in the oil. They do they don't centrifuge the oil and seperate all the stuff out. BITOG has more on this.

In saying that it's probably the best method of testing, but just know it's also limited...

GC is probably one of the best but i know my dealership will void my warranty for using something different to 5w30... they are so lame... i hate them...

6SPD_FTW

I understand what you're saying. Insolubles normally should be below 0.6%. On the Altima and the Z, I never had anything higher than like 0.3%. If it's high, then you have more trouble than just what's IN the oil. Means you got some issues with oil or air filtration. I guess...just throwing that out there.

Late,

Trav

IDZRVIT

When I was in the navy I had the opportunity to work in the lab where oil analysis was done and performed the actual analysis. At that time it was called SOAP - Spectrographic Oil Analysis Program. Similar elements were measured as in the UOA. It wasn't measured by percentage but rather in ppm. Samples of the oil were filtered and mixed with a solution in test tubes (can't remember exactly as it was twenty years back) and analyzed in the spectrographic apparatus. This was done routinely on a monthly basis for the engines, gearboxes, pumps, etc. Everyone should be aware that molecules in the components such as lead in journal bearings leech out into the oil from the constant contact between the two. So there was always a reading. From trending and comparison of results from sister ships with identical propulsion systems conclusions were drawn as to whether there was actual wear or just 'leeching'. Wear was normally identified by a spike in the ppm. VA (vibration analysis) was recommended to ship's staff to perform on the suspect bearing. Anyway, for you guys that get UOA's, pay close attention to the results. You don't have the luxury of doing VA and you don't want to be tearing down your engine looking for the bearing that may have resulted in a spike in the UOA report that may have some wear but not worn anywhere near the point of catastrophic failure. I will say this - changing the oil will not repair a worn part! However, after changing the oil and reviewing the UOA results, it may confirm a wear condition if there is another spike or if there isn't a recurring spike, then the original analysis may have been an anomaly - nothing is 100% perfect.

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