Honda Civic oil

If your owners manual and your oil cap say's to use 5w30, I would unless you in hot in a hot climate? then you could use 10 w30. bob

or are more interested in saving a few drops of gas than having your engine last a long time you should use 5W30. 10W30 is better for other conditions.

Better?

How so?

I don't really know why people recommend this. 5W30 is only thinner at lower temperatures, when you want it to be thinner. It may contain more viscosity index improver (which can break down over time) than 10W30, but with the quality of oils today I can't see that being an issue if you change your oil often enough.

And even then it is thicker than [even a 15w/30] when at running temperature.

Huw

This is incorrect and shows a fundamental lack of understanding. It is not rocket science so it continues to amaze me how people cannot comprehend such a simple concept, much less be so convinced that they have the confidence to post such misinformation.

Huw

Neither your assertion that 5W30 is thinner when hot or your conclusion that this provides superior lubrication is true. See

$FILE/PCMO-2210.pdfto comapre the specs for 10W30 and 5W30 Motor Oil. At 100 degrees C, 10W30 and5W30 have exactly the same viscostiy. Thicker oil does not alway provide superior lubrication. In an engine with large clearances, higher viscosity (thicker oil) may be a better choice or it may not.

Ed

Approximately 9/15/03 08:45, Mike Walsh uttered for posterity:

All else being equal, a 10W30 oil and a 5W30 oil will have exactly the same viscosity at 212 degrees F. More correctly this will be within the range for a 30 weight single viscosity oil at that temperature. The 5W will be thinner at low temp than the 10W.

As for providing better lubrication, if the engine has been designed for 5W30, you wouldn't want to be using a 10W30 in it.... not enough lube at cold temps.

This would be true if oil met specifications, which according to tests I have read most oils don't. In any case I am more interested in what my oil pressure gauges reads than in what the books say. An oil that is rated for a smaller range, e.g. 10W30 is more stable and will provide good lubrication for a longer time than an oil that is rated for a wider range, e.g. 5W30.

Engines were not designed for 5W30. When the federal government mandated higher fuel mileage standard the manufacturers started recommending 5W30 in the same engines that they used to recommend 20W50 in. The only design changes were to correct problems with 5W30, e.g. harder camshaft to prevent rapid wear.

read most oils don't. In any case I am more interested in what my oil pressure gauges reads than in what the books say. An oil that is rated for a smaller range, e.g. 10W30 is more stable and will provide good lubrication for a longer time than an oil that is rated for a wider range, e.g. 5W30.

higher fuel mileage standard the manufacturers started recommending 5W30 in the same engines that they used to recommend 20W50 in. The only design changes were to correct problems with 5W30, e.g. harder camshaft to prevent rapid wear.

Modern 5W30 oil to the latest Service Grade (SL) is not the same as 20W50 from ten years ago. I cannot find any credible information that leads me to believe an engine manufactured in the last 20 years will wear faster if it is lubricated with SL Grade 5W30 instead of 20W50. The only parameter that might be of concern is bearing oil film thickness. I have read one SAE paper (by GM) that attempted to experimentally measure bearing oil film thickness experimentally. This paper made it clear to me that even 5W20 oil will provide a sufficient bearing oil film thickness in an engine in good condition. For a worn out engine, I suppose 20W50 might be necessary. Personally I believe you should follow the vehicle manufacturer's directions no matter what lore your father may have passed down to you. BTW, I have never had an American vehicle that recommended 20W50. All of my current diesel tractors recommend

15W40. One thing you should remember - for an engine in good condition, the viscosity of the oil actually increases as the oil is "used."

Ed

"C. E. White" wrote

. Personally I believe you should follow the vehicle manufacturer's directions no matter what

an American vehicle that recommended 20W50. All of my current diesel tractors recommend 15W40.

It is probable that, in common with almost all engines, there is a range of viscosities recomended for any particular temperature range encountered. The tractor will most likely be also recomended to use a

10w/30, even for high temperature regions if other properties are also met. For instance it will probably be approved to use a super universal [combined transmission and engine oil] of 15w/30 or better still the superior, though lighter, 10w/30 formula.

viscosity of the oil actually increases as the oil is "used."

This is only true for lightly stressed engines which may dirty their oil. I have one [tractor actually] which is used often at its full rated output for hours on end, where if the oil is left in for the recomended maximum or more, the viscosity will quite suddenly break down and the oil will get extremely thin to the point where it is consumed at about a gallon a day. As soon as it is replaced with fresh oil, the consumption returns to about a gallon every 100 hours or so.

At least in my area, 15W40 is the only viscosity recommended. In colder climates a 10-30 might be recommended, but when the tractor is being worked hard, the difference in oil temperature will be trival from one climate to another (at least until you get to the artic).

Your tractor is suffering from excessive blow-by. I did say an engine in good condition. I had an old gas tractor that would actually increase the amount of "oil" in the pan until you worked it really hard. When the "oil" got really hot, a lot of the blow-by products would evaporate, and I'd be several quarts low in a matter of hours.

Ed

manufacturer's

diesel

better

That is quite true for all water cooled engines but air cooled engines will have greater variation and are particularly sensitive to high ambient temperature.

break

No visible blow-by whatsoever. Very light breather with an exceptionally dry pipe. Viscosity breakdown in highly stressed engines is quite common and results from both heat and mostly shear stress. My engine is a turbo-intercooled air/oil-cooled Same/Deutz/Fahr but water cooled V6 and V8 Mercedes units are also noted for this behaviour when run at their max. SHPD oils are a minimum requirement but the latest API CH4 [or Mercedes 228.3] long drain standard improves the acceptable drain interval by about 25%. At the moment I am experimenting with one of only a handful of available fully synthetic

10w40 Super Universal oils to assess its resistance to breakdown. Its long term use in a power shift transmission [JD PowerQuad] was somewhat curtailed by the wet brakes delaminating and depositing iron filing contamination so as to need the oil changing at less than 500 hours use. The brake linings had lasted just less than 5000 hours which is about average for any manufacturer in the same conditions.

Huw

I did say an engine in

increase the

Approximately 9/16/03 06:43, Mike Walsh uttered for posterity:

read most oils don't.

??? Cite ??? By any chance can you describe this mysterious specification and any reliable tests that show oils are being massively mislabelled? Is a fairly simple spec, the oil should be in a given *range* of viscosity at 100 C, whether or not the oil is 30, 30W, 10-30, 10W30, 20W30, etc. etc. Is a simple single temperature test, is it not? One could note that oil tends to run hotter than 100 C. in most modern engines if one wanted tho.

Really. Why does thicker oil provide "better" lubrication?

Yep.

have read most oils don't.

No kiddin'....I want to see this too!

If you're not experiencing consumption and if you run in variable temps (not merely hot all the time) then you're perfectly fine sticking with a 5W30 oil. I prefer Pennzoil and Chevron Supreme.

However, as indicated earlier 10W30 is almost always more stable becasue of less viscosity index improver used. Most 5W30s will begin to thin by 3,000 and some will be a 5W20 by 2,000 miles. In fact, some seem DESIGNED to thin out to enhance fuel economy. The stuff will only thicken up with oxidation and by that time it is a less-than-ideal lubricant and is probably leaving deposits inside your motor.

So, if you are in warm weather all the time (50F and above) you could go with a 10W30 ... no problem.

I would not, however use a 20W50 oil. It's too thick for all but basket-case cars and your engine may even run hotter while it fights the greatly increased hydrodynamic drag. Even a 15W40 is a bit thick and would only use it once consumption with a 10W30 became a problem.

Afraid oil these days is too thin? Well that's where the barrier anti-wear additives come in. I like an oil with a good dose of moly and borate esters (boron). If you don't want to spring for Schaeffer or Red Line Oil, consider the two mass-market brands I mentioned previously.

--- Bror Jace

I have read three different SAE papers that all show that 5W30 thickens with use. If your oil is thinning it is most likely because your engine has excessive blow-by.

Ed

read most oils don't. In any case I am more interested in what my oil pressure gauges reads than in what the books say. An oil that is rated for a smaller range, e.g. 10W30 is more stable and will provide good lubrication for a longer time than an oil that is rated for a wider range, e.g. 5W30.

fuel mileage standard the manufacturers started recommending 5W30 in the same engines that they used to recommend 20W50 in. The only design changes were to correct problems with 5W30, e.g. harder camshaft to prevent rapid wear.

Well I don't agree entirely, thinner oils also flow more rapidly thru the motor and its bearings, keeping those parts cooler. And get where it needs to be sooner in cold weather.

Provided the oil has sufficient shear resistance to avoid metal to metal contact, thinner is often better all around. It's not just a CAFE conspiracy.

Although I am a liitle suspicious of Ford's push to use 5w-20.

Regards, Al.