READ PLEASE! 5w20 vs 5w30 engine life? opinions ?

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READ THIS OVER ON A MUSTANG FORUM BUT WANTED TO GET SOME OTHER OPINION ON THIS ORIGINAL LINK http://www.allfordmustangs.com/forums/2011-mustang-talk/379969-5w20-vs-5w30-debate-rages.html SAE 5W-20 Motor Oil Should you use it in your vehicle?? The answer is simple: You get about 1% better fuel economy, but you get 30% shorter engine life ! The above statement is based on real life experience and is comparison to SAE 5W-30 Motor Oil. Unfortunately, in order for you to fully understand that short answer, some lengthy explanation is in order... The SAE (Society of Automotive Engineers) developed, in June 1911, the SAE J300 standard that specifies Engine Oil Viscosity Classification. Before SAE came up with this scheme to classify oils by their relative viscosities (in plain terms that the motoring public could easily understand) there was no simple way to tell how oil would behave in automotive engine when hot. Back then oils had no W rating, which stands for Winter. Since cars were seldom driven in winter this was not a real problem. The roads were generally impassable and vehicles usually not capable of starting when temperatures approached freezing. The original SAE viscosity ratings were based on how quickly a specific quantity of motor oil flowed through a test orifice when heated to operating temperature (specified as 100°C or 212°F). The SAE Viscosity Number or Grade according to the initial SAE J300 standard was simply an average time in seconds that tested oil would take to flow through the test apparatus. Since SAE did not want to confuse the public with hundreds of numbers and the simple test yielded different times for different experimenters, it was decided to assign the grades in range steps rather than absolute test values. Therefore the SAE Viscosity Number according to the SAE J300 standard was (and still is) an approximation and NOT an exact measure Any oil that took from 5 to 14 seconds to flow would be SAE 10; Oil that would take 15 to 24 seconds would be labeled as SAE 20; Oil that took 25 to 34 seconds would be SAE 30; And so on until SAE 50; In the original SAE J300 specifications there was no SAE 5 or SAE 60 grade. The science of Rheology was not well developed at that time, and automotive engineers were neither scientists nor physicists. Therefore it took several years before the SAE J300 staircase was translated from time measurement numbers in a crude instrument into a scientific viscosity values for viscosity expressed in Poise. By then the J300 SAE Standard was also recognized, but not adapted by API (American Petroleum Institute) and hundreds of oil producers had thousands of cans of oil with SAE numbers already in the market place. So as not to confuse the motorists, who by then gotten used to buying motor oils identified by SAE numbers, the numbering system that by then did not relate to anything comprehensible was maintained. As far as the author of this article could find the oldest SAE numbering system for motor oil was as follows: SAE Viscosity Grade Flow Test time (seconds) in Apparatus Viscosity in centipoise @ 100°C 10 under 14 4.00 ( 2 - 5) 20 15 to 24 7.45 ( 6 - 8) 30 25 to 34 10.90 ( 9 - 12) 40 35 to 44 14.40 (13 - 16) 50 over 45 19.10 (17 - 21) The last column is not part of the SAE J300 Viscosity Standard, but rather shows the average viscosity values (and the range) of oils that were typically sold within the specific SAE Grade. The SAE Viscosity Numbers only indicated the oil’s ability to flow at the test temperature of 100°C; The SAE Viscosity Number did not in any way imply suitability for any purpose or quality or performance of the oil that carried such identification; The test was also performed ONLY on FRESH oil, so no durability or stability was ever implied; During the early days of motoring, motor oils were pure petroleum oil produced with little to no enhancement during processing, nor did motor oils contain any additives. Therefore eventually oil marketers started to label all petroleum oils in the market place with the SAE Viscosity Numbering system numbers, so that consumers could quickly identify what viscosity the oil was when "at engine operating temperature". This early specification was important for simple reason, oils sourced from different oil fields and different regions had vastly different viscosity index (which at that time was not yet well defined, although recognized by oil people). Viscosity Index (VI) is nonscientific arbitrary value that simply represents the slope of inverse relationship of oil viscosity to temperature. All petroleum will flow slowly at room temperature, and much faster when heated up. therefore as the temperature is increased viscosity is decreased; This is known mathematically as inverse relationship, I.e. if one value goes up (temperature), then the other goes down (viscosity); Some oils although they were thick at room temperature would flow as easily as water when hot, yet others that were not as thick at room temperature would not thin out as much. This means that two oils that appeared to have an identical viscosity at room temperature (which was usually the temperature at which the motorist would purchase or pour the oil into the engine), could have totally different viscosity when heated up. The early automotive engineers even then recognized the viscosity, as very important quality; And above all the viscosity when at operating temperature ("hot") was universally agreed to be far more important quality than viscosity at ambient temperature; This was especially important since one oil sourced from Gulf Coast, could be thick when cold, yet unable to protect the engine adequately when hot; By contrast another oil from Pennsylvania, a lot easier to pour when ambient, could be just right for automotive engine when hot; The example of the thick when cold and really thin when hot, was oil with low viscosity index: VI of 0 – the thick black Gulf Coast aromatic crude would behave like this. The second example of the not so thick when cold and not as thin when hot, would be the oil with high viscosity index. VI of 100 (then thought to be the best possible) – the amber oil which came from the oil fields of Pennsylvania and consisting of the paraffin crude that made Pennzoil and Quaker State world famous. Although viscosity index was eventually defined by API, it was not of concern to SAE and still today is not part of any SAE specification. The actual viscosity at each extreme of engine operation is what automotive engineers agree on as most important specification-- it is this premise that led to the development of multigrade oils. Over the 70 years that the SAE J300 Standard has existed, a number of shortcomings were discovered and the standard has been amended numerous times. Although its evolution is of interest, the discussion of its exact detailed history is far beyond the scope of this article, here is in brief what has happened over the 70 years. SAE 60 grade was added as the need for thicker oil in aviation and heavy duty engines became apparent. SAE W grades were added in 1952 as it became apparent that engines could not be started in colder climatic conditions with some SAE 30 oils. The W (Winter) performance was originally defined as viscosity at 0°F or -11.8°C. SAE 5W and later SAE 0W grades were added as thinner economy oils needed to be defined. Additional test specifications for winter performance were added to W requirements as engines failed mechanically in cold climates immediately after initial startup, due to oil starvation. SAE 15W and SAE 25W grades were added to further narrow the performance definitions in winter climates. In 1970's minimum high temperature high shear specifications were added for performance at 150° C, when it became obvious that engines suffered from excessive wear or even seized at high speed high temperature operation such as long distance interstate driving or towing in hot summer climates. So the changes to SAE J300 Standard were usually (until very recently) a reaction to fix an existing problem with lubricants that caused engine problems in service. This was generally due either to viscosity breakdown when hot or failure to flow when cold; in either case resulting in catastrophic engine failures. The last few SAE J300 Standard changes were proactive. They were legislated jointly by the auto and engine manufacturers, as well as the lubricating oil producers, before problems in the field occurred, based on research tests in the laboratories--and therefore done in anticipation of problems. Many of these specification changes were necessary because today’s cars equipped with electronic fuel injection and electronic ignition will start immediately at much lower temperatures, than vehicles made just a decade ago. Also, because of the proliferation of smaller engines with lower engine oil capacities that produce much more power that put oil under much greater mechanical as well as thermal stress. The current SAE J300 Engine Oil Viscosity Classification Standard is tabulated below: Revised DEC 1999 (yes, this is the current standard as of 4-21-2011) SAE Viscosity Grade Cold Cranking Maximum Viscosity @ Specified Temp Cold Pumping Maximum Viscosity @ Specified Temp Hot Viscosity @ 100°C Kinematic(cP) Hot/High Shear @ 150°C Minimum (cP) 0W 6,200 @ -35°C 60,000 @ -40°C > 3.8 5W 6,600 @ -30°C 60,000 @ -35°C > 3.8 10W 7,000 @ -25°C 60,000 @ -30°C > 4.1 15W 7,000 @ -20°C 60,000 @ -25°C > 5.6 20W 9,500 @ -15°C 60,000 @ -20°C > 5.6 25W 13,000 @ -10°C 60,000 @ -15°C > 9.3 20 > 5.6 < 9.3 2.6 30 > 9.3 < 12.5 2.9 40 >12.5 < 16.3 2.9 40 >12.5 < 16.3 3.7 50 >16.3 < 21.9 3.7 60 >21.9 < 26.1 3.7 Based on our experience 99.8% of motorists have absolutely no idea what the SAE numbers on motor oil labels really mean. They assume that the simple recommendations in their vehicle owner’s manual are cast in concrete, and that the SAE viscosity of recommended motor oil can not be changed under any circumstances. The fact that it is quite appropriate to either increase or decrease the manufacturer's recommended motor oil viscosity, if it is appropriate for your particular operating conditions and desired engine life. Here are some real time, as well as laboratory tested, ultimate and unchangeable truths: The ideal oil viscosity for motor oil used in conventional piston engine operating at the "normal" engine operating temperature is equivalent to SAE 30. (In range of 9 cP to 12 cP @ 100°C); If you use thinner oil (SAE 20 or less), under normal operating conditions there will be less resistance to motion due to the lower viscosity, resulting in better fuel economy. However, this gain in fuel economy does not occur without costs: Increase in oil consumption due to lower viscosity (can be offset by better seals); Increase in oil consumption due to higher volatility (can be offset by using synthetic oil); Decrease in engine service life due to increased boundary wear under some operating conditions (this will cost more per mile driven or per engine operating hour); If you use thicker oil (SAE 40 or greater) under normal operating conditions there will be more resistance to motion due to the higher viscosity, and therefore worsened fuel economy. This loss in fuel economy is somewhat compensated for by: Decrease in oil consumption due to higher viscosity; Decrease in oil consumption due to lower volatility; Increase in engine service life due to reduced boundary wear and better separation of parts in relative motion; If the ambient or operating temperature is increased from the ideal or normal (70°F/212°F) then the oil viscosity must be increased to assure same level of protection and lubricating oil film integrity; It is not just better, but a must to use SAE 40 oil at 100°F ambient and SAE 50 at 120°F ambient. If the load is increased such as when towing, the oil viscosity must also be increased to assure the same level of protection. (use SAE 50 when towing); If the engine speed is increased such as during long distance high speed driving in low ambient temperatures (so that the bulk oil temperature is not increased) the oil viscosity could be decreased--that is SAE 20 is preferred to SAE 30 oil (this however works only for manual transmission vehicles where vehicle speed and engine speed are proportional and higher RPM can be maintained by more frequent downshifts if necessary); If the load is decreased then the oil viscosity can be decreased (when an empty tractor/semi-trailer is driven at 70 MPH on Interstate, it is OK to use SAE 30 instead of the SAE 40 that is specified and appropriate when the Tractor is hauling a maximum load at 55 MPH); The most important factor related to long-term engine durability and component wear seems to be the High-Temperature / High-Shear-Rate specification shown in the last column of the SAE J300 Standard; For SAE 20 oil it is 2.6cP minimum; For SAE 30 oil it is 2.9cP minimum; For SAE 40 oil there are two specifications 2.9 cP the same as SAE 30, and 3.7 cP the same as both SAE 50 and SAE 60 (but why?) Well the first specification is for light-duty engines (cars that are not expected to last beyond 70,000 to 150,000 miles) and the second for heavy duty engines (that is engines which are expected to last up to 1,000,000 miles). That is why oils which are labeled as HD (Heavy-Duty) must satisfy the second SAE 40 specification of 3.7 cP. [ed] The lower viscosity number for multigrade motor oils may be changed (increased generally) depending on the lowest ambient temperatures at which you will start the engine. For most of the US and Canada 5W or 10W oils are fine, however for warmer sections of the country 10W (or even 20W) may provide less wear at startup. OK the final scoop on SAE 5W-20 and SAE 0W-20 oils: For many years in the USA automotive manufacturers and importers have been subject to CAFE (Corporate Average Fuel Economy) standards that were passed by US Congress during fuel shortages of the 70's and fear of America running our of gasoline in just a few decades ([ed] which BTW, didn't happen). When enacted these laws forced US auto manufacturers to attempt to match the fuel economy of then popular Japanese Imports. Car manufacturers get a hefty Federal fines for not meeting the CAFE MPG standards, for every 0.1 MPG by which they fail multiplied by the number of vehicles they sell. That is $5.50 per each 0.1 MPG by which the standard is missed multiplied by the number of vehicles sold in previous model year--which runs annually into millions of dollars. Success in the car industry is measured ONLY by how many vehicles have been sold in last 10 days. Therefore every 0.1 MPG by which you can raise fuel economy does matter, and manufacturers are quite willing to sacrifice engine durability. After all, the sooner you wear out your new car, the sooner you will buy another and that is positive impact on the 10 day sales statistics. You will definitely get better mileage using SAE 5W-20 rather than SAE 5W-30 oil but not by much, optimistic estimates are less than 1%. The bad news is the about 30% reduction in engine life (from 100,000 miles or 10 years to 70,000 miles or 7 years) caused by the thinner oil. Only manufacturers who have 3 years or 36,000 miles power train warranties currently recommend SAE 5W-20 oil to be used in their 2000 through 2006 model vehicles. By contrast Mercedes-Benz that offered 4 years or 50,000 miles warranty not only specified SAE 5W-40 motor oil. And in the USA to assure that only that oil grade was used, provided periodic maintenance free to all its customers (free maintenance was offered by Mercedes-Benz from 2000 model years through 2004 model year, it was cancelled on 2005 model cars and SUV's) All heavy-duty engine manufacturers recommend SAE 40, SAE 15W-40 or SAE 5W-40 oil. The final choice is yours, you can get 1% better mileage or 30% longer engine life. If you are leasing a vehicle, then the better mileage parameter is definitely more important as well as cost effective. You just do not care how long will engine last on a car that you will only operate for 24,000 to 36,000 miles. But how many gallons of fuel you will burn will make a difference. Summary: SAE 5W-20 motor oil is great–it yields better EPA numbers than SAE 5W-30 oil = better CAFE compliance = lower Federal Fines for not meeting minimal CAFE standards. It typically save the manufacturer about $15.00 per vehicle in CAFE fines; SAE 5W-20 motor oil increases oil consumption–more oil gets used, which is great for oil companies everywhere; SAE 5W-20 motor oil increases mechanical wear, reducing engine life–that way you will buy new car sooner; Posted by CliffyK at 8:31 AM Edited on: Wednesday, February 22, 2012 9:38 PM
 
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By the time the "lighter is better" types get through trashing this you'll think the poster is an automotive terrorist. I'll stick with T6 5-40 and feel better about it now.
 
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Let's say that everything "Cliffy" has written is true. Let's also note that any twenty grade oil will allow the engine to outlast the Mustang in which it's installed. What would be the point of 30% longer engine life when the vehicle as a whole has 0% remaining life? Engine wear related to manufactures' oil grade recommendations is simply not an issue, since engine wear does not determine the useful life of a vehicle. If a twenty grade scares you, just use a thirty and be happy.
 
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Originally Posted By: HerrStig
By the time the "lighter is better" types get through trashing this you'll think the poster is an automotive terrorist.
Or worse! LOL popcorn2
 
Very true, but the folks brain washed by years of publicity from the CAFE bean counters are convinced 5/20's are the way to go. The article is very good at pointing out the relationship between engine load, outside temperature and viscosity. Engines subject to severe duty use in high temperatures and loads are most in need of the heavier grades and I was most amused to see a picture of the oil grade advice page for one car that had an actual warning not to use 5/20 in hot climates, when the same manufacturer lists 5/20 as the only oil to be used in the US.
 
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We have a real-world, large number comparison of 5w/20 vs 5w/30 longevity going on right now: Ford vs GM. Ford has recommended 5w/20 for at least a decade while GM continues with 5w/30. If 5w/20 really shortened engine life by 30%, don't you think Ford would be suffering in comparison to GM? It seems to me there is no real perceived difference in engine longevity between the two. The bottom line seems to be that 5w/20 allows an engine to last every bit as long as 5w/30 if the engine was designed with it in mind. Also, let's not forget that a disproportinate amount of wear occurs on cold start-ups, where a lighter grade of oil is helpful. But as others have said, if you feel beter going "thicker", have at it.
 
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Quote:
For most of the US and Canada 5W or 10W oils are fine, however for warmer sections of the country 10W (or even 20W) may provide less wear at startup.
Thick oil logic at its finest.
 
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Originally Posted By: HerrStig
By the time the "lighter is better" types get through trashing this you'll think the poster is an automotive terrorist. I'll stick with T6 5-40 and feel better about it now.
Well said!
 
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Originally Posted By: FoxS
Quote:
For most of the US and Canada 5W or 10W oils are fine, however for warmer sections of the country 10W (or even 20W) may provide less wear at startup.
Thick oil logic at its finest.
Why would that be true? Whats confusing about this article is how it bounces back and forth between startup and running weights. If "90% of engine wear occurs at startup" is still true, why we worried about the other 10%?
 
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Originally Posted By: Danh
We have a real-world, large number comparison of 5w/20 vs 5w/30 longevity going on right now: Ford vs GM. Ford has recommended 5w/20 for at least a decade while GM continues with 5w/30. If 5w/20 really shortened engine life by 30%, don't you think Ford would be suffering in comparison to GM? It seems to me there is no real perceived difference in engine longevity between the two. The bottom line seems to be that 5w/20 allows an engine to last every bit as long as 5w/30 if the engine was designed with it in mind. Also, let's not forget that a disproportinate amount of wear occurs on cold start-ups, where a lighter grade of oil is helpful. But as others have said, if you feel beter going "thicker", have at it.
Yep, and don't forget that Honda has been running 0W20 in Japan since 2001 with no issues...and the key point is: engines designed to run on 0w20/5w20 have shown no issues.
 
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Originally Posted By: bubbajoe_2112
Originally Posted By: Danh
We have a real-world, large number comparison of 5w/20 vs 5w/30 longevity going on right now: Ford vs GM. Ford has recommended 5w/20 for at least a decade while GM continues with 5w/30. If 5w/20 really shortened engine life by 30%, don't you think Ford would be suffering in comparison to GM? It seems to me there is no real perceived difference in engine longevity between the two. The bottom line seems to be that 5w/20 allows an engine to last every bit as long as 5w/30 if the engine was designed with it in mind. Also, let's not forget that a disproportinate amount of wear occurs on cold start-ups, where a lighter grade of oil is helpful. But as others have said, if you feel beter going "thicker", have at it.
Yep, and don't forget that Honda has been running 0W20 in Japan since 2001 with no issues...
If you have statistics that prove it please provide. The only thing I've seen from Japan is a massive amount of imported late model rebuilt engines for sale on eBay. Thousands of them.
 
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Don't be silly. The Japanese know nothing about engine longevity. And Ford is the least competent of the domestic manufacturers. They took the biggest bailout. Proof that they are engineering boneheads.
 
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People still think of the way oil lubricates in terms of how syrup flows over pancakes. The article is well written, but ULTIMATELY it argues for 5w30 from intuition, not from science. Intuition leads astray. Oil viscosity has only very little to do with film strength. And the difference between 5w30 and 5w20 is not that great anyway.
 
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Think about how the average Crown Vic is driven. In Police use lots of idling and then shortish periods of going flat out. In Taxi use they probably rarely get above tickover very often. My old employers London Ambulance Service had the 3.5 V8 lump in them, I believe it was originally a Buick design but the all alloy construction was not liked/trusted. Even driven hard they would change up well before the redline, you could only get them above 4/5k revs if you used the 1, 2, 3 lock out. Then they really flew! They were also the most reliable engine in use in London, occasional rattley top ends after almost certainly being run low on oil, most issues were electrical or to do with the carbs. When the vehicles eventually came out of service, some had been doing Emergency calls for a minimum of 11 yrs, some as long as 16 yrs. The engines and autoboxes were stripped out and sold onto a V8 specialist up near Norwich and are certainly now running around in Kit cars, TVR's, Cobra replicas or classic Rovers or old Range Rovers and Land Rovers. The engines would rarely if ever rev above 2k. I think they ran the V8's on Castrol GTX 15w40 for their entire life, at least that is what was written on the barrels at the fitters I frequented. Do I think they would have been less reliable on 5w20 or similar. Yes, I do, I suspect some would have worn out. The fact that few if any did is all you need to know about the oil choice. I suspect the engine life would have been similar on a thin oil, maybe the fuel consumption would have been better, I once worked out I got 6mpg out of a tank one summer with the aircon on. So maybe we could have got 6.06 mpg on 5w20. If an engine is designed for thin oil then I will use it, no need not to, but I would be concerned if the engine was back specced to use it. Manufacturers are only worried about the engine getting outside the warranty period, after that who cares is their attitude. Though they will happily sell you a new engine. I would happily use 5w20 Motul Specific in a petrol engined Land Rover or Jaguar specified to run on it. Would I then be happy to run 0w10 if it even exists? No, I wouldn't. Would I run 5w40 in the same engine? No, I wouldn't. It isn't an issue of thick or thin oils for me. It is why are the US car makers back speccing a thinner oil, what reasons are there for this and what research has been done. Does anybody really think Government Policy has anything to do with ensuring your vehicle runs for many years. Governments want the economy to grow, they want the big car companies to sell cars. Scrapping cars like they did in the UK and US did not benefit the environment, it benefitted the car makers. Saving 0.5% fuel usage will not benefit the car user. It might help the government make some spurious environmental target. Look at Euro 3 and Euro 4 in Europe (specifically the diesel Pathfinder) A Euro 3 auto would give 26-28 mpg overall, a Euro 4 auto with DPF will give 21-24 mpg. Another example would be the Vauxhall Zafira 1.9 cdti 120bhp. The 2006 model was mapped to give linear response and had good throttle response. The 2007 model was remapped to meet a spurious EU emissions target, result it had no throttle response from a standstill, the delay between pressing the loud pedal to moving was at least a couple of seconds on occasion. When driving they were sluggish, press the throttle harder and they would drop a gear and s ream up the road almost on the redline. Why, they had been remapped to meet a target. How to fix it? Get it remapped and it was back to normal. The power delivery on the later ones was both harsh and certainly not beneficial to engine and gearbox life. Call me a thick oil junky or whatever. But Government policy is never going to benefit the End user.
 
I thought GM was recommending 5/20's, in fact almost every car sold in the US seems to have 0 or 5/20 stamped in the manual by the CAFE bean counters?? I've been looking at Ford engines mostly, so perhaps some person could look up a few GM engines to see if they are recommending 30 grades or not.
 
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Try searching the forum next time, this topic is one that has been discussed way too many times and I'm sure most people here no longer give a [censored] about it and would rather have discussions where there isn't a tragic pile of political opinion and gross ignorance of basic engineering...
 
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Originally Posted By: bullwinkle
There's an awful lot of old Ford modular V8s around that have been on 5W20 their whole lives-ex PI Crown Vic taxis, mostly.
Oh Sir, how do you know that these vehicles haven't seen "grade" upgrades due to consumption and leaking?
 
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