cristphoto

How much penalty in gas mileage is there by using 5-30 oil vs 5-20? Anyone ever done a comparison? I've used 5-20 Mobil 1 in my 06 TL since the first oil change at about 7000 miles. I'm considering going to 5-30 Mobil 1 once the weather warms up if there is negligible loss of economy.

01tl4tl

Run the 5-30
The whole 5-20 thing is another govt bs thing called CAFE- the average fuel economy across the line of a maker. So by having slightly less drag for the testing with 20w, (at normal operating temp) they reduced the cars fuel use by a tiny amount, but anything to make the average look good.
Its all about the numbers you know!

Test revealed the 5-20 was the MINIMUM- the 20 part- you can use, and not ~seriously DAMAGE~ the engine. I want more than min. spec on every part of my TL

KJSmitty

To answer your question,
The 5W-20 will/should give you the better mileage. I actually see about 1mpg difference. Remember, whether its cold or hot, once your engine is at 190 degrees+, the 5W-30 will always have a greater viscosity than the 5W-20. So don't just think that just because its hotter outside the 30 will garnish you the same mileage in the summer that the 20 will in the winter. Oil just doesn't work that way. My mileage always drops in the summer due to overall AC use.

Now, I'm no expert on oils but you can search the site for numerous 5-20/5-30 "weight debates." The "experts" will tell ya that both provide excellent protection year around. Some stats reflect the 5W-20 is superior - I believe in it's "shear" resistance..

Try them both - neither will be of any harm to your TL. Let us know what your mileage numbers are.

Cheers

KJSmitty

Interesting - I'll be the devils advocate here,,,
Because if 20 was the minimum you best be running a straight 20 or 30 weight - "20w or 30w." (or never run your engine unless the oil is 190+ degrees)

As mentioned above, even with a 5w-30 multi-weight your only going to be some where in the 5W+ arena until your engine is about 190 degrees or more... So no, 20 would not and could not be the "minimum viscosity" required to prevent serious damage to the engine... That's why you see 0w-20 etc. multi weight oils... Even 0w provides good protection.

I actually had a client that religiously ran a straight "5W" oil year around in his GM vehicle in Montana. The gentleman had the car the entire 8+ yrs I worked at the dealership - it had over 100K miles. The engine is probably still running today.

It's all good.

01tl4tl

I was not clear in my statement- cant you just understand my thought process???~
The wife doesnt get half of what I say either

What I meant was: that for running the engine at normal operating temp, the 20 is the min SAFE viscosity AT TEMP, yes the COLD number is different issue, mainly- if you live in Canada run 0w something and in the states 5w whatever
BUT for what we are taking about, in non abbreviated statement, is 5w20 will yield slightly better mileage that 5w30

which oil is better protection at normal operating temp?? when being used in a rev pushing manner for the pure enjoyment of it all???
the 5w30
because the 30 part is better-thicker protection for all those parts hammering against each other several thousand times a minute.
Thats based on everything I have read and many years working with performance street and race cars.
google CAFE Corporate Average Fuel Economy and see what I am talking about

01tl4tl

Disclaimer!!!! Due to my limited scope of knowledge on the following subject:

I dont ~believe~ that 190 is a change-over in viscosity temperature number,
rather that it works the other way.
Pour oil from a jug that sat out overnight and what you get is GLUUUG GLUUGGG
IMO- Its not 5 weight then... just waiting to transform into a thicker oil at a certain temp.
The special additives and whatever secret sauce the oil contains ~must~ allow it to FUNCTION as a 5w for an- as yet undetermined- amount of time/temp.
This is just my guess, and a good reason for me to do some more research on viscosity ratings and test protocals.

Piston engine Airplanes run a straight 50w oil, and in Alaska winters- you have to drain the oil out and put in on the stove overnight. Otherwise it would be too thick in the morning to allow the engine to crank over without killing the battery.

Yes, we do allow the engine to reach good temp before takeoff, when you can rev the engine without it stuttering and the oil temp is in the green, now- lets go flying!!!!