I really depends upon where you live. I ran synthetic 15w40 in my truck until I reached 33,000 miles. The cold mornings (low 30s) made the starts rather rough. My last oil change I switched to Shell Rotella Syntehtic 5w40. The truck runs much better and starts alot faster with smoother idle. However, it rarely gets above the high 70s to low 80s here.
In the south, I would not run anything except 15w40.
Red Line, Amsoil and Royal Purple are the easier ones to find. Schaffer's also makes a good 15W-40 synthetic, but good luck finding it. And you won't find any of these brands at Walmart or your typical chain auto stores. You'll have to look on-line or at a more performance orientated independent auto parts store. Cost, about $7 to $10 a quart.
Shell Rotella on the other hand is sold at your local Walmart for $17-$20 a gallon.
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I was thinking of using mobil devac 1 on my next oil change. what are the benifits/drawbacks of using a 5w-40 rather than a 15w-40?
2006 crew cb long box 4x4 with 13k
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I use 5W Rotella Syn since last winter when it was so cold. I had the oil changed a couple of weeks ago and went with the 5W even though it's summer. My truck definitely likes the 5W MUCH better in the winter and I haven't noticed any depravation in summer
I run Schaffers 9000 5w40 synthetic all year round. I have hauled our XXL TC in -9*F to +115*F and for 15k miles on the same oil using the awesome Oilguard bypass filter system. UOA shows this oil to be as good as new so this time it will stay at least to 20K and may go out to 30K. To be determined by UOA.
UOA will let you know how good your oil is doing and I doubt there is any made that hangs in there better than Schaffers 9000 5w40. Oh and it costs $3.45 a qrt.
Actually, the 5 in 5-40 means that the oil flows the same as an oil with an SSU viscosity of 5 at 100 degrees F, and the 40 means that the oil behaves the same at 210 degrees as 40 weight oil.
All that being said, the oil is your choice as long as it meets the proper vis and API rating.
The lower number in multigrade oils is the base weight of the oil and it is viscosity stretched to the higher number with viscosity index improvers. That is why you won't find a dino 5-40. It simply cannot be stretched that far. 1 to 3 is considered the reliable max, such as 10-30. 10-40 is quite questionable in it's reliability.
Synthetics can safely be stretched much further.
Wow ... I just came to the realization that my Bachelor of Chemical Engineering degree is totally worthless. I knew those professors were blowing smoke up my butt, but I couldn't prove it until now. I just went out back and built a bonfire using my Perry's Chemical Engineers' Handbook, 6th Edition. It has to be outdated and you wouldn't believe it cost $150 in 1994. LOL!!! /ubbthreads/images/graemlins/grin.gif
No offense intended just poking some good clean fun, but "now that there post is funny." Boy, I am thoroughly confused now.
Ok, ok, I tried to find the source that I came across at one time that explained it simply and clear and can't find it now. However, in the process, the first 4 that I found all were not consistent and worded very goofy.
So, I found this from Valvoline that is clearer than the others. And yes, I was mis-informed, or as I found now, it was explained so bizarre it made sense. /ubbthreads/images/graemlins/laugh.gif However, maybe it's right, but the definitions of Multi-viscosity and Multi-weight is being confused??
Just a few clips:
"This allows a 10W40 oil to flow like a 10W at cold temperatures and a 40W at higher temperatures. In other words, multigrade oils are formulated to pass viscosity tests across a range of weights. For example, 10W30 meets the requirements for 10-weight at cold temperatures and 30-weight at high temps."
I don't know the exact test parameters, and even those are not consistent between sources. But cold temps seem to be tested at either 0-100 degrees C or at 100 degrees C which makes more sense.
"...very few may know that the "W" refers to "winter," not "weight." And most of us have no idea what the weight-rating numbers actually mean other than that the vehicle's manufacturer specifies a particular viscosity."
Next, and talking about "Multi-Viscosity":
"An oil cannot be multi-viscosity, but it can be multigrade by meeting the viscosity requirements for SAE 30, 40, 50 or 60 and one of the sub-zero "W" viscosity requirements. At one time, some oil companies labeled oils SAE 10W, 20W30—as if the oil could be 10W and 20W at the same time. This is impossible because 10W is measured at -20 degrees C and 20W is measured at -10 degrees C, which eliminates the multi-viscosity theory."
Tested at 100C or a sub zero??? See why we're all confused? Even the guy who aren't confused? LOL /ubbthreads/images/graemlins/biggrin.gif
"The viscosity classification of a motor oil according to the system developed by the Society of Automotive Engineers and now in general use. “Winter” grades are defined by viscosity measurements at low temperatures and have “W” as a suffix, while “Summer” grades are defined by viscosity at 100ํํํํํํํ°ํ C and have no suffix. Multigrade oils meet both a winter and a summer definition and have designations such as SAE 10W-30, etc." THIS might be a good read for someone. /ubbthreads/images/graemlins/cool.gif
There, I hope everyone is as confused as I am now. The thing I'm not confused about is what oil(s) should be run in my truck. Thank god I don't need a Chem Eng. degree to buy and change the oil! /ubbthreads/images/graemlins/biggrin.gif
thanks for the help. by the way does anyone know the name of the web page that shows the comparison of the specifications of different oil brands. i thought it was a SAE page but i have not been able to find it.
Family, you are now pretty close, and I wouldn't argue with "all of the above". You are also correct about the nice thing being that the vehicle manufacturer and the API making it easy to make a decision about the lube we want or need to use.
As a process operator that manufactured lube oil, I ran viscosity tests at 100F and 210F. The lab followed up with their own tests, and the Shell refinery I worked at was positively anal about their oil quality.