Higher Oil Viscosity?

120K mileage is nothing these days with modern engines. Keep using the Mobil One and it'll probably go to 300K and beyond with proper maintenance.

The engine sounds "tight?" How does it sound differently than when it is "loose."

There is no need to change oil type.

Jeff

If you listen real close at the tailpipe....... a "loose" motor can be heard to utter "Hey, sailor.... wanna get lucky?".

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. ** Posted from **

The oil viscosity presently used is the recommended viscosity. What are you recommending?

It sounds like what you have been doing is working. It may be a mistake to change if there has been no recent change in operating conditions. It is my understanding that 5w30 oil is made with a higher quality stock with a high quality additive package to achieve the 5w rating. It doesn;t sound "broken" so don't try to fix it.

Lugnut

The owner's manual recommends "Motorcraft SAE 5W-20 Premium Synthetic Blend Motor Oil." I believe that's what the other Tom is referring to.

SC Tom

He likely thinks you should be using 5W20.

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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.

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That presents a follow up question, would switching to 5 - 20 present any problems since I have been using 5 - 30 from day one?

I would never use higher than recommended viscosity, unless I had a valid reason. The lower viscosity oil is needed with new engines because the tolerances are less.

Jeff

You could use the 5W30 if you found one that meets Fords WSS approvals. But, since there isn't such an animal...

And the High Temperature High Shear specs aren't.

-That- totally ignores Fords oil specifications, which happen to be a whole lot more important than simplistic viscosity myths.

Baloney. 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.

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Stick with the 5W30 if it's working for you. I wouldnt switch back to the 5W20. The 5W30 probably GOT you to the 120K with less wear than the 5W20...

Ford switched from 5W30 to 5W20 because 5W20 gave ~1% better gas mileage...period. There was NO change in the internal engine components/clearances that I am aware of. The slightly heavier oil will IMHO protect better under load and at higher rpms. Ford lists

5W30 as an alternate spec for many engines.

Note that diesels and many European gasoline cars use heavier oil for better protection under load/hgh rpm. My 2005 Jetta 2.0l takes 5W40, many diesels take 15W40.

Yes, you can go TOO heavy, but the 5W30 should be fine in a healthy engine.

Don (who runs BMW/Castrol 5W30 synthetic in his 03 F150 4.2 and 99 Taurus Duratec 3.0) Don Byrer KJ5KB Radar Tech & Smilin' Commercial Pilot Guy Glider & CFI wannabe kj5kb-at-hotmail.com

"I have slipped the surly bonds of earth; now if I can just land without bending the gear..." "Watch out for those doves..."

Actually, they're not. The tolerances are smaller, because, with robots, engine makers are able to have smaller tolerances.

Gee, that means that with lower viscosity, there is lower friction. Lower friction is good for an engine.

Yet, there is more friction with the higher viscosity oil.

One thing you have not accounted for is that today's oils are better than the oils of 10 or 15 years ago.

And this is based on what evidence?

Evidence that a thicker oil is better, please.

Jeff

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 fact.

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 oil.

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.

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