5W-20 second thoughts

[Dave Sherman]

After driving around for a little over a week, and actually watching the gas mileage, I can't tell any significant drop going from 5W-20 to 5W-30. I can still get around 32 MPG on the highway, and it's hanging around the usual 24 commuting. This morning it was cool enough to have dew on the car, and normally that would mean some clattering during the warm up. No clattering that I can tell.

Since another thread here mentioned some camshaft galling on K-series engines, I might just stick to 5W-30. I was curious to see how much of a hit in the gas mileage it would take, but so far it's looking like almost no difference. Since I keep a spreadsheet of all the gas mileage, I just made a note at the last fuel stop that I changed to 5W-30, so I can see if it actually makes a statistical difference over several tanks.

 

[Smokescreen]

I just pulled in my best tank ever at 46.29mpgUS or 5.08L/100km, 112% of EPA still on PP5w30 with my '09 Corolla with original '09 ECU code. I expect to get even better in the next coming months.

 

[Gary Allan]

Anyone doing long mileage routinely may get nothing. The 1-2% difference can be easily masked behind being behind on tire pressure adjustments or head winds for that matter.

The winners are those who never reach full operating oil temp. They shorten the curve to that number with lighter oils. The deeper you get into the warm up event, the less pronounced the difference.

The two oils are most alike at normalized operating temperatures. That would be when you would expect the fuel economy to be most alike too. I got statistically insignificant differences between 5w-20 and 20w-50 on single warm up 200:400 mile back to back events. The 20w-50 was the nitpicker's winner.

Running the same engine around town for 5minute jaunts and 15w-40 vs. 5w-20 assessed a 30% penalty.

YMMV

 

[Audi Junkie]

Originally Posted By: Dave Sherman

Since another thread here mentioned some camshaft galling on K-series engines, I might just stick to 5W-30.


That was pretty shurely shown to be a metallurgy problem. Aftermarket cams, like Skunk, have shown no failures.