Use of motor oil weights

Typo. I meant 25C.
Yes I’m saying 5W20 at 25C is thicker than 20W50 at 100C.

At 25C, 5W-20 is 5 weight

At 100C, 20W-50 is 50 weight.

Tester

“Weight” is not a direct measure of viscosity.

I have the older 4.6L. The consensus for that engine is that it can take either 5W20 or 5W30. Different years with the same engine call for different oil. The difference is the EPA rating because a thinner oil provides for less drag and better mileage.

If you are concerned, only run it in the summer if you live in an area where the winters are colder. I would change it out and just waste it as recycled oil IMMEDIATELY if any codes show.

Someone recently gave me a 5 quart jug mostly full of some store brand 20W50 oil. I hate to waste it so it will be used as chainsaw bar oil. Chainsaw bar oil is usually a straight 30W.

http://knowhow.napaonline.com/understanding-oil-weight-numbers-bottle-mean/

Tester

I was responding to viscosity change affecting vvt. My 4.2 is an Atlas I6.

Did this just turn into “Bob is the oil guy”?

I wonder what the poster decided to do with the 5w30?

Variable valve timing has been around for 25 years, at least 90% of the time the correct oil viscosity goes in during an oil change, why do we not see the consequences of using the wrong oil in these $10,000 engines?

A VVT actuation delay of a fraction of a second will not cause an increase in pollution that would require the check engine light to illuminate. Cylinder deactivation is different, the valve deactivation must be synchronized with injector on/off actuation, out of time will cause an increase in hydrocarbon emissions, that is why variable displacement engines monitor oil pressure/viscosity.

Some manufactures offer a list of alternative viscosity oil for those who travel outside of the EPA’s jurisdiction. The same engine that calls for 0W20 in the Sonoran desert can use 5W40 in the Persian Gulf.

I have enjoyed the information on oil but I think we can all agree, just use the oil the manufacturer recommends.

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I was referring to @TwinTurbo 's comment about having a 4.2L . It’s since been clarified .

These weight claims are false. I bought a bunch of different ‘weights’ of oil, weighed them, found them all the same weight!

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I wonder how “weight” ever got used with motor oil. Crude oils do differ in density, but not motor oils.

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I have a car that specifies 0W20 and that is what I use. That being said, the car is only made in one factory but sold around the world. The same model in China can take 10W40 conventional oil but with shorter change intervals.

The consensus is that the engines are not made differently. The same exact engine is coming to the US as is going to China. All the internal parts are the same no matter what country the car is made for.
Some people who feel 0W20 is too thin have gone to a 5W20, 5W30, 0W40, 5W40 synthetic. The big downfall is a reduction in fuel mileage but no other harm has been done.

I would not be too concerned with using 5W30 in the Ford engine. 10W40 would probably be a different story.

Two things have been overlooked here. First the OP can look into his owners manual to see what it says about alternate grades of oil. 5w30 may be allowed but with conditions like changing sooner etc.

Second, those

may be older and of a different API spec. The oil must match the API spec as well as the grade.