That oil is Fine. I use 20 - 50 in all my 4 cyl and 6 cyl and 8 cyl
cars. As the Engine runs and you put miles on the car the oil Viscosity
breaks down from heat , gas in the engine.
As you drive say 1000 mile etc your oil changes to say - 16w - 45 and
lower and lower as you put on more miles. I would never use 5w - 20 or
5w - 30 as the oil will break down real thin like water - so to speak.
This will damage the engine.
Brian - Las Vegas
Nothing's changed significantly with respect to engine design.
The reason for manufacturers' recommendations for lower-viscosity oils
has more to do with fuel economy. Federal rules mandating greater
Corporate-Average Fuel Economy (CAFE) has led all the manufacturers to
recommend lighter oils, because it takes less power to pump the
lighter oil through the engine. Less power used producing oil
pressure means less parasitic load, and less fuel used.
You can "get by" with the thin stuff, because their aim is
only to get their product to last through the warranty period.
There's nothing wrong with using a bit heavier oil, in the interest of
making the hardware last somewhat longer. As always, consideration
should be given to engine size and the expected operating ambient
temperature (to name just a couple of parameters) in choosing the
The oil channels in modern engines are much smaller than in "ye olden dayes" and
the high viscosity oils just can't get to the upper cylinder areas as quickly as
the thin stuff. There's also the matter of startup oil pressure. I have real oil
pressure gauges on my vehicles, and they all will peg the gauge at 100 psi on
cold startup. Put in that pre-90s "syrup" in one, and the engine seals wouldn't
last very long, oil pressure relief valve or not. Longevity? I have three
vehicles that run very well, they each maintain at least 35 psi at idle, and use
almost zero make-up oil between 5,000 mile changes; this is on 5W30 Mobil One,
the only oil they've ever seen. Engine longevity? 232,000+ miles, 109,000+
miles, and 158,000+ miles. Thicker oil, my a**.
And other hard heads will find it IS true that CAFE has dictated the
use of lighter oils. Are heavier oils necessarily better? Or worse?
NO. It depends on a lot of factors - but I will ALWAYS run a slightly
heavier oil than recommended by the manufacturer both in warm weather
and when running under high load conditions. "Ideal conditions" do NOT
EXIST in my world.So I don't use oil recommended for "ideal
Use the manufacturer recommended weights as many have said. I personally
use Shell Rotella Synthetic 5W-40 in my 5.2L Ram & 3.8L Town & Country. I
have excellent oil pressure and consumption is great, too. The Chrysler
uses less than 1/2 quart in 5000 miles and the Ram uses 1 quart every 3000
miles. They have 139,000 & 160,000 miles respectively.
Hope that helps,
. All naturally-aspirated and turbocharged four-stroke diesel engines using
high or low-sulfur fuels, and four-stroke gasoline engines
. Mixed fleets of diesel and gasoline engines, and/or old and new equipment,
such as newest exhaust gas recirculation (EGR) engines with lower exhaust
particulate emission standards
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