I wouldn’t run anything thicker than what the manufacturer calls for. These new engines aren’t using 0W‑20 and 0W‑16 just to chase EPA numbers, they’re built tight. The bearing clearances, the oil passages, the crank and rod journals… all of it is designed around thin oil that moves fast. You need that quick flow to build the oil wedge and keep the bearings floating. If you dump thicker oil in a modern engine, it can’t squeeze into those tight clearances, the flow drops, the wedge collapses, and you end up with wear you’ll never see until it’s too late.
The oil pump and the VVT system are built for low‑viscosity oil too, so going heavier can starve the top end and mess with cam phasers and timing chains. Stick with the viscosity and additive package the engine was engineered for; that’s where the protection is.
I was a mechanic, not an engineer. I haven’t torn down these newest 0W‑16/0W‑20 engines. But I’ve worked on enough motors over the years to know what happens if you ignore the clearances. These modern engines are built tighter than ever, and thicker oil just doesn’t belong in them.
Hi Louis. I've done non technical research on this over the last several months. (Meaning I talked to a service manager at a German repair specialist, watched some YT videos and read some blogs).
My 2016 Audi and my 2019 VW both have the same basic 1.4 TSI turbo engine. Just the year is different so maybe minor changes. The 2016 called for 0W40, 0W30, 5W40 and the VW calls for 0W20 (VW 508/509 spec -- not the standard 0W20). I doubt they made changes to the engine that it requires the 0W20. The Audi engine is specced at 150hp despite being older while the VW is specced at 147hp. That comes down to the more aggressive timing on the Audi to be a bit more performance oriented.. But they're in the same ballpark. I've had a VW dealer tell me it was to chase the uttermost MPG rating to hit the fleet standards.
There are more accounts of premature engine wear on engines specced for the super light oils. And I've seen enough of the reputable YT oil experts (not random guys but guys who have been mechanics for decades, are oil engineers and test oil professionally etc) and they recommend, mostly, to not use that light of a weight. Plenty of examples of burned out pistons or whatever they were showing using the lighter weight.
I know some people are against mixing oil weights but the last one I did on the VW I did about 50-60% of the specced 0W20 VW 508/509 spec, and the rest the "older" 0W40 or 5W30 I had that is VW 502/505 IIRC. It's the VW spec oil I use in the Audi. I didn't research it but I assume the additives package is similar, being that older versions of the engine take the older spec and its VAG (VW Group). Big and stuck on stuff that works. Slow to make changes.
I'm willing to take the risk as I didn't like the images I saw of engines damaged by too light of oil.
I think it is Chevrolet that had an issue with a motor specced at 0W20. The fix was to move to 0W40 synthetic. Several other brands have major issues with light oil. Here is the Google AI issue when I asked about car manufacturers with light oil issues:
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The Global "Double Standard" Controversy"
Automotive teardown communities frequently point out that many of these same global engines (from
Subaru,
Toyota, and
Honda) explicitly permit thicker oils like 5W-30 or 10W-40 in their owner's manuals for European, Asian, or Australian markets. They only strictly mandate 0W-20 or 0W-16 in North America to comply with strict domestic fleet efficiency standards. [
1,
2]
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I'm not an expert and I didn't stay in a Holiday Inn Express last night
I also ballasted the track on the diorama base. Not too bad for a day so far. Almost lunch time!
