My understanding is that they would have the same(ish) base oil but the 5W30 would be the one with less VII, especially if we're looking at oils from the same category, eg a euro 5W30 A3/B4 MB 229.5 compared to a typical 5W40 of the same category.the winter rating decides how thin the base oil is. VII adds viscosity on both ends (cold and hot), only relatively more at the top end.
so, the 5w40 has thinner base oil and more VII
If a person is willing to pay for a more extensive analysis through Polaris labs, they can tell you exactly what part the metal is coming from. It’ll cost a couple hundred bucks. I know several people that have done this on class 8 trucks. Money well spent considering engines can be upwards of $40,000 on class 8 trucks.Not to discourage UOA testing but consider this;
Suppose the next series of UOA's shows a slight uptick in wear metals.
Is the increased wear metal content coming from cylinder/ring/piston-pin wear, crankshaft journal/bearing wear, cam wear, or from the timing chain?
Just curious but if there are several components in the engine with the same metal being used, then how could they ascertain the source of the wear?If a person is willing to pay for a more extensive analysis through Polaris labs, they can tell you exactly what part the metal is coming from. It’ll cost a couple hundred bucks. I know several people that have done this on class 8 trucks. Money well spent considering engines can be upwards of $40,000 on class 8 trucks.
I have wondered the same thing. As I've stated in other threads, I have 2 (Ford) Duratech's (which are based on the Mazda MZR engine). The 2.0 in my 14' Focus is GDI and the oil is beginning to darken about 2K into the OCI while the 2.5 in my 16' Escape is still clear looking when I change it (usually about 6K OCI). It help's that the 2.5 has a 5.7 qt. sump vs. 4.5 for the 2.0.*How significant is soot content in a GDI engine with respect to engine wear (i.e. timing chain) ? My '17 Sonata GDI engine's oil is pretty dark by 2K ~ 3K miles .
There was a good study published on this exact topic sometime last year. Moly was found to have a fairly significant (positive) impact. High amounts of ZDDP appeared to make things worse. Found it: https://www.stle.org/images/pdf/STL...
The above linked study was rather interesting. However, I suspect the test was run using rather low viscosity oil. My speculation is that additives become the lubricant when oil viscosity is too low to prevent rapid wear. For over 100 years, industry has been using chains for power transmission, often in seriously heavy duty applications. So chain life was a major factor in operational costs, machine accuracy, down time and so on. Industry studied the problem and found the longest possible chain life required just two things. 1) 30 viscosity oil. 2) extremely clean oil. Despite what many here say, oil changes are the way to remove micro particulates from your engine oil. Unless one is performing particulate counts and knows the percentage of soot in the oil, extending OCI's beyond the severe service interval is risky. We've known about chain wear forever. This is nothing new and surprising. Timing chains have been failing for as long as they've been used. With wildly differing results on the very same engine models. The reason for early failures remains the same as it's ever been. My suggestion: Choose a quality synthetic oil of sufficient viscosity, change it frequently. The Ford Ecoboost chains that are failing take 25 man hours to change and the parts cost is near a $1000. That's nearly $4000 to replace chains, often before 100,000 miles. The oil change is cheap insurance.