Motor Oil Viscosity

The only way to find out is to get the used oil analyzed several times while alternating between 5W-30 and heavier oil, but I've been told it takes at least 6 analyses to get statistically meaningful results.

I used to drive a VW Rabbit (Golf) in southern Arizona with Mobil 1 synthetic 5W-20 and changed it every 10,000 miles and had the used oil analyzed. The wear numbers were always low, and the engine had 150 PSI compression when I sold it at 140,000 miles. VW recommended heavy oil for this engine, straight 40 for most of the year, and they considered even 20W-50 too thin. So a much newer design engine should have no problems with 5W-30, especially in a cooler climate like yours. Also not just Ford and GM but also many reputable car makers now recommend thinner oil, so I doubt it's bad

- I hate the idea of using 5W30 wt. motor oil - even tho it is a factory recommendation.

what do you think?

mho vfe Your manual normally gives a range of acceptable motor oil types or viscosities depending on the type of driving, temperature, etc. I think it is perhaps wise to stick within those recommendations, particularly if you have a warranty in place.

What is your basis for hating the idea of using 5-30 engine oil.

I'm trying to understand why you would want to choose to ignore the information in the owners manual. Possibly it is because you think the collective wisdom of a few usenet group posters outweighs the collective widsom of the petroleum, chemical, mechanical and mettalurgical engineers employed by car makers and oil companies.

..ouch

I need to get the Funk and Wagnalls out so I can spel gooder.

I think you need to think.

What gets hotter, the ambient temperature in Texas, or the burning gasoline?

If you're that concerned about it, use a synthetic oil rather than go thicker. I'd only go to a thicker oil if you actually have an oil pressure problem.

nate

In the last few days, that might be debatable, Aarcuda;>)

5W20 or 5W30 oil will save a few drops of gasoline during the first few minutes of driving. 20W50 will keep keep your bearings and camshaft lobes from wearing out after the oil thins out because it is running at around 200 deg.F. It's your choice.

snipped-for-privacy@webtv.net wrote:

Oil viscosity recommendations are no longer driven by "...the

There's a little thing in the U.S. known as CAFE: Corporate Average Fuel Economy ratings. Lighter oil viscosity improves (slightly) the fuel usage for a given vehicle. As long as the august experts mentioned above agree that most of the vehicles in question will last through the warranty period without an unacceptable number of claims, the manufacturers are going to recommend the thinnest oil they can. Remember that manufacturers are NOT interested in your car lasting a long time. They depend on new-vehicle sales, and they will do anything they can to get you to buy newer, sooner, more indulgently. 15W40, or even 20W-50, is fine for vehicles in "temperate" climates.

Well, supposedly that viscosity range means that it will perform like a

30-weight at the hot end, and in the old days when singleweight oils prevailed, that's what we typically used in healthy gasoline engines. As they got older and worn out, people would use a heavier oil.

You didn't say what kind of car you have, or what kind of age/mileage/condition.

Diesels are different, typically wanting a heavier oil and also, these days, calling for differences in other parameters -- but since your manual calls for 5W30, I assume you have a gasser.

Anyway, look carefully at the owner's manual. You might find that in summer, a 10W30 or 10W40 is okay and you only need the "5" end in winter. Some cars, though, really seem to want the effective thinness of a 5Wwhatever while warming up.

Finally, if the engine is young and healthy, you might consider a fleet-duty 5W40 *synthetic* . With the viscosity range that synthetics sometimes offer (in addition to their other advantages), you can have your cake and eat it too; it just costs more to see the dessert menu.

Finally, buy quality filters. One of the ways that they often cheapen down a loss-leader filter is by skimping on the anti-drainback valve. On some engines that's pretty significant as one of the finer points of how to protect your engine immediately after startup no matter what oil you're using.

Cheers,

--Joe

If you're that concerned about it, use a synthetic oil rather than go thicker. I'd only go to a thicker oil if you actually have an oil pressure problem.

nate

Again, do you have hard data that this will do as good a job as, or better than, the thicker oil?

I think the Fly might be closer to the truth than any of us would like to believe.

Fly's comment seems to be on track. =3D=3D

In short, I personally have to problem in selecting a motor for my use - regardless of recommendations which I deem to be broad in scope, and self serving.

I do appreciate the sincere responses to my post.

mho v=83e

I continue to stand by my statements, which somewhat follow, Mike and Fly.

Lower weights winter, higher weights summer. Nuff said here, and my '86 Celebrity and my '89 Eagle and my '96 Grand Am Am and my '03 Cavalier do ing just fine with the method, thank you.

This is why you should have a calibrated oil pressure gauge in your vehicle. Otherwise, you're just guessing. Use the gauge.

nate

Why do you call something as famous as CAFE "a little-known thing"? And why would light oil be recommended even by car makers that have no problems meeting CAFE standards, like Honda?

Send some to Wisconsin. 8-)

well - knifeblade, good for you, and I'm glad you have a formula worked out that satisfies your needs. atta boy!!!!

me, in short - I use 10-w-30 wt. havoline the year around in a climate that the temp usually does not exceed 100=B0, or fall much below 32=B0. I have 170K miles on one,

107K miles one, and 21k miles on one, and never add a full quart between

changes. (wouldn't have to add - any.) btw - you pour in the recommended

amount at the time of an oil change, the filter "holds" some, you take a reading on

the dip stick later, and you might assume - it needs oil, when it doesn't, so I only

add oil if it gets down to / below the add-oil mark, which it seldom if ever does. adding oil against a hedge - could result in an over-fill which is a no no. the owner's

manual and filler caps say use - 5w30 wt.. and I use havoline 30wt. in my lawn

mower / edger, and change it yearly. when maintenance / repairs is needed,

they get it, none of this - do it tomorrow stuff. btw - the edger is a one-owner

bugger, 37 years old, original belt, bought new for about 40 bucks. one thing I don't

do - is try to make improvements on a cars design / engineering - that the motor

companies have spent x-no. of dollars on. and, someone mentioned oil filters with

check valves (back-flow preventers), something that some users might not be

aware of, but I have for years used the same brand of oil filter with the - check valve feature.

happy motoring, and keep it greased - good.:--)

mho v=83e

I think the operating temperature of any well designed, liquid cooled, engine is largely independent of ambient temperatures.

Whether 5w50 works better or worse than another grade is another issue...

-Greg