Not ALL Ford engines recommend the 5W20, and those that do, the
majority recommend synthetic or synthetic blend. You CAN use 5W30 in
any engine that recommends 5W20. The critical cold flow is the SAME on
both. 5W20 gains a couple tenths in the CAFE over 5W30 - and that is
the ONLY reason it is recommended.
No need to change oil type - but when I run an engine hard in high
temps I ALWAYS use heavier oil. (and all my vehicles are, by
definition, high mileage, because I buy them at 100,000Km plus, about
10 years old for $5000 or less and drive them 'till they are done -
usually well over 15 years old.
I take care of them, but they earn their keep.
The tolerances are virtually the same as they were 10-15 years ago.
The low viscosity oil is for fuel economy, almost exclusively.
And using 5W30 in place of 5W20 has NO detrimental effect on
lubrication because when it is cold, where lack of oil flow due to
viscosity would be a problem, they are virtually IDENTICAL. The oil is
thicker cold than either of them are when warm (and thicker than a
5W50 would be when hot as well)
The ideal oil, as far as I'm concerned, would be a 5W50 or 0W50
synthetic (only because non synthetics are almost impossible to
produce with that wide a viscosity rating and still be "oil".)
They use low viscosity oil now because they CAN. The thin oil today
does a better job than thin oil could do 15 years ago in many ways -
but is still not as effective as a slightly thicker oil could be.
No, they are able to maintain CLOSER tolerances. They can produce
finer finishes, more repeatably. There are less "high spots" or "tight
spots" which means the engine does not require a complex breakin - but
the specified clearances are virtually the same in today's engines as
they were in "precision" engines 30 or more years ago.
No, not necessarily. There is less VISCOUS friction. That is good for
economy, and as long as everything goes according to plan (like that
EVER happens for long) it is good for the engine. However, what is
good for fuel economy is NOT always good for engine life. A thicker
oil film provides more protection - to a point - as does an oil with
EP additives (like Zinc) which are no longer allowed because WHEN, not
if, the engine burns some oil it poisons the catalytic converter.
Thick oil is less prone to burning - so thicker oil with zinc is just
as good for the converter as thin oil without.
Saying today's engines last longer because of the thinner oil would be
a faulty observation because so much more has changed - not just the
oil viscosity, or the oil composition, but the fuel composition as
well. Lead free gasoline is likely the largest contributor to longer
engine life due to the fact phosporous and other similar compounds are
no longer required to keep the lead suspended and avoid lead buildup
on valves, guides, pistons, and ports. This keeps the acidity of the
crankcase in check, making everything last a bit better.
No more "friction" ANd precious little difference in pumping loss.
Not necessarily better, but definitely different. They are better in
some ways - but that still has not ballanced out the loss of EP
performance due to removal of zinc and other metallic EP agents.
Which? That it would be the best, or that it is difficult to produce a
non-synthetic with that broad a viscosity range and still be "oil"?
The (long chain) polymers used to enhance viscosity index DO reduce
the "oilyness" of oil somewhat. That is a known fact
0W50 synthetic oil DOES exist - that is a fact. 5W50 non synthetic is
extremely rare if it exists at all - and that too, my friend, is a
If you understand oils at all you know that a 5W50 is still thicker
when cold than it is when it is hot. An SAE5 oil cold is thicker than
an SAE50 hot. So a 0W50 or 5W50 oil still thins out when hot.
The "cold" number affects cold start oil pressure and the spped at
which lubrication is acheived on a cold start. The "hot" number
affects the film strength(indirectly) and the oil pressure and
lubrication of the engine when hot (and under load) and has NO EFFECT
AT ALL on cold start lubrication.
The ONLY "problem" with an oil with a high VI is a fraction of a
percent difference in fuel economy.
40 years of experience is all I have as evidence, but there is a lot
of research out there that backs me up.
If thin oil is better, use straight 5 weight, or even kerosene or fuel
Today's manufacturers are specifying the thinnest oil they think they
can get away with to coax that extra 1/10% fuel economy out of their
engines. If they use the thin oil to qualify the engine, the MUST,
under American law, require/reccomend that oil for every-day use.
OK - When this "thin is better" crap started I was a dealer service
manager and I was replacing camshafts and timing chain tensioners.
LOTS of them. Didn't matter how often the oil was changed, in hot
weather cams, tensioners, and chains were failing.
My brother was at a Ford shop and they had cam problems on the 2.3,
particularly in the south. They found using 10W40 and 20W50 oil
completely eliminated the problem
I said "enough" and went back to using 10W40 in the winter and 20W50
in the summer.
Guess what? I wasn't replacing camshafts, chains, or tensioners on my
customer's vehicles any more!!! I was still replacing them on engines
using 5W30 oil in 90 degree plus summer temperatures - following the
manufacturer's recommendations. When I told the "road man" what I was
doing (because my warrany claims were WAY down) he said he could not,
legally, recommend it because the vehicles were certified by the US
EPA and Canadian MOE for their fuel economy using the thin oil. He
also said he could not with a clear conscience argue with the results
and there would be no effect on the vehicle warrantee if I continued
doing what I was doing.
The heavier oil was extending the life of the engine significantly.
And I NEVER had a bearing failure on the engines I serviced this way.
MANY went well over 300,000 km (and we are talking 1980's vintage 4
and 6 cyl engines).
Even the notorious 2600cc Mitsu/Mopar "Hemi" would last if it ran
20W50 in the summer, with 3000 mile change intervals. Following the
6000 mile "factory recommended" change interval with the "factory
recommended" 10W30 or 5W30 oil (or any combination thereof) and the
tensioners went bad and the timing chains got noisy and let go before
100,000 (often before 100,000 km - or 60,000 miles)
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