Synthetic oil

[GRU]

i may be crazy but i have logged my instant mpg at 58mph for pretty much every trip and it's always showed about 44.5 mpg. Now that i switched to synthetic i'm constantly getting 46 mpg at the same speed

[mwebb]

there are many compelling reasons to use only synthetic

oils
ACEA A3 B3 A3 B4
or better for all engines in the viscosity range the engine was designed for

while Fuel Economy may improve marginally it is not the primary reason to use the absolute best oils available for your particular application
engine life is
cat converter life is
particulate filter life is (in diesel engines)

with proper service intervals
the more expensive correct oils are cheaper to use , your engine service life and cat converter service life will be hugely improved over dogshnit oils

this is a complex subject
that evolves with new engine design and new cat converter design
study and learn at the BITOG forums

never use any oil
that does not meet ACEA specifications OR minimum OEM specification for your application

for instance
today
in GM engine s dexos1 for gasoline dexos2 for diesel
in VW Audi , minimum oil specification in (most) gasoline engines
is VW 502 and Minimum in current VW Audi TDi engines is VW 507
never use dogshnit oil in any VW Audi engine that does not meet minimum
specification for the application

unless
you enjoy
pain

[Frank Lee]

Never heard of dogschnit oil- seems all the major brands "meet or exceed specifications".

Up until about a year ago all my stuff ever had was conventional oil- I do have synthetic in one of the Tempos, I guess as a test. I usually use Halvoline or even Wallyworld SuperTech oil, but if something else is on sale with or without rebate my stuff gets fed that too.

The last 40 years of doing that (in addition to ignoring the "severe service" "traditional" change interval of 3000 miles) has shown to me that my engines have had no lubrication issues even though where I live they'll see -40F to +100F ambient temps; what happens is that road salt kills the rest of the car way beforehand.

In the past I've spent time digging around BITOG; biggest thing I learned was that yep, there are a lot of recreational oil changers in this world.

P.S. I don't own any of that uppity VW/Audi ****; I'd agree if you want that garbage to live you better use their uppity oil in it too.

[2000mc]

see frank you really do need some good oil, more for spraying at the under body, but you need some oil good for that

so what is the service life of an engine changed according to manufacturers specs when changed with conventional vs synthetic?

[Frank Lee]

Ha- right you are!

[AaronMartinSole]

Originally Posted by Ford Man

Personally I've never had any problems with conventional oil in about 1M miles of driving, with one of my cars being at 518,700 miles on the original engine.

What's your secret to keeping that car going that long on the original engine? That's insane!

[Diesel_Dave]

Earlier this year I switched my diesel truck over from Shell Rotella 15W-40 conventional to Amsoil Series 3000 HDD 5W-30 synthetic. It's one of the few mods on my truck that's had an immediate, noticable impact. I was expecting someting on the order of a 3-5% FE improvement, but saw a 5-10% improvement.

I think part of the reason for that is the fact that I run such a large engine and I suspect during normal comminuting my oil pan hardly ever gets up to "full" operating temperature--I'm usually almost halfway there before my coolant temps get all the way up and the oil temp will lag the coolant temp.

However, I do think it's more about the viscousity than whether it's "synthetic" or not--now days the line between synthetic and non-synthetic is getting blurry anyways.