Super Tech 5w-30, 6,200 miles, Hyundai 3.3L GDI

I wanted to see if I could run a quality full syn oil to 7,500 miles with this particular engine.

I used Oil Analyzers because I believe their testing method for flashpoint and fuel dilution is more accurate than Blackstone’s.

Of the miles on this oil, 2,200 were “pure highway”via two separate interstate trips. The remaining 4,000 miles were “loop driving,” i.e., on the I-275 loop or stop and go driving.

Super Tech was used because that’s what my brother put in it shortly before I acquired this ride.

Initially, my bigger concern was (is) intake valve deposits owing to the GDI. My plan was to use Valvoline Modern Engine for 7.5 k OCIs. M-1 is in it only because I got it on sale.

The engine runs great and the UOA backs that up, other than more fuel dilution than I’d like.
Right now I’m thinking of keeping the OCI to 6k. What oil I use next is still not certain. Probably VME or just stick with Supertech or Costco.

Personally, I think the TBN of 3.1 is pretty good considering the fuel dilution.

And yes, the engine had been run at normal operating temperature for several miles before the sample was taken.


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Northern Ontario, Canada
We have that 3.3L in our 16 Sorento. It is very good.
I tend towards changing the oil more often on GDI engines.
FWIW, KIA requires 3,750 mile OCI in Canada.
If it was my car, with your drive cycle, no more than 5,000 miles on oil changes - because GDI.
Saint Nazianz, WI
My biggest concern is that the kinetic viscosity is just above the threshold between 30 and 20 weight oils. It should start around 11 for this oil and dropped to 9.7 (threshold is 9.3), not too terrible but I think you would effectively have 5w20 in your crankcase if you pushed the OCI to 7500 miles.
Saint Nazianz, WI
It wouldn’t be the first time we’ve seen a 30 weight oil shear down to a 20 weight.

I just remember when Hyundai began their push towards using direct injection engines during the last decade and were adamant about not extending an OCI beyond 7500 miles. Much of it had to with the limitations of their OEM oil filter but I believe time has informed us that direct injection is particularly hard on motor oil. I think your UOA reinforces that notion.


New York
I've previously stated that the oil in my 2.0 Duratech with GDI gets darker much quicker than the 2.5 non-GDI Duratech in my wife's Escape.
For this reason (and the fact that the 2.0 has a 4.5qt. sump vs. 5.7qt. in the 2.5) I change the oil sooner than recommended in the 2.0.
Since Ford specs. Motorcraft synblend 5w20 in both....I'm thinking that using a synblend or dino 5w20 (which really is a synblend) at 5K in the
2.0 is fine (I'm thinking full synthetic at that interval is a waste). Thoughts?

I make this analogy because my thinking would be the same if I owned a 3.3 Hyundai GDI...If I owned a turbo GDI I'd stick with full synthetic and still reduce the OCI to 5K.
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