VIIs & differences in 5w20, 5w30 & 10w30 oils

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472
Location
Hampshire, UK
Back in the days when I was still a wage slave, I would do Singapore->Brisbane->Sydney->Melbourne->Adelaide->Perth->Singapore in a week. I'd just do meetings wherever there was an oil refinery and spend the rest of the time in taxis, hotels and being shuttled around by Ansett. I did that on and off for three years. My last ever trip in 1990 was a holiday before I returned to the UK. We did Darwin, Kakadu, drive down the Stewart Highway to Alice, do The Rock and then fly to Cairns for the reef. Brilliant! In all that time I never once saw snow! Are you sure you didn't Photoshop that picture??
 
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860
Location
SD - South Dakota
Originally Posted By: Joe90_guy
It seems some vehicles are now fitted with an integrated coolant/oil heat exchanger as standard fit. The clever thing about these things is that not only does the rapidly heated engine coolant warm up the oil from cold but the direction of heat flow reverses if the engine oil gets too hot (the coolant can't ever go much above 100C otherwise it would boil). So it also acts as an oil cooler. Very clever!
All true, but an antifreeze mix of 60/40 will not boil until 230+ (110c). Even in an unpressurized system. Under pressure,that number Is higher yet.
 

shiny

Thread starter
Messages
286
Location
Phoenix-ish, Arizona
Originally Posted By: AcuraTL
In a hot area like Phoenix, not only is a 5-30 or 10-30 ok, I recommend it. If 5-20 is ok in your engine in a cold climate, say Michigan, it stands to reason that a 5-30 has to be ok in your climate seeing how the 5-20 will be thicker at startup and at full operating temp in a cold climate vs a Phoenix climate on any given day. You could make the argument that a 0w40 on a 100F day will be about the same viscosity as a 5-20 on a 50F day or running at 230F vs 180F I live in a Phoenix-like climate and have run Redline 0-40 in my Acura that specs 5-20 for a while. From its first oil change around 4,000 miles it got RL 5-30. From 90k to its current 135k it's had 0-40 in it. i wouldn't think twice about a 5-30 or 10-30 in your climate. It's absolutely no thicker than a 5-20 in a slightly cooler area. ... ... But yeah, a cheap 10-30 or a decent 5-30 will be great in a Phoenix climate in a car that calls for a 5-20 in all climates.
Thank you (thanks everybody!). I appreciate not only your advice but the reasoning behind your advice. So on our colder days where I might be starting the car with 35-40*F temps, will a 10w30 flow as fast as 5w30? Is there enough difference between them to make a difference?
 
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124
Location
Tx
Originally Posted By: shiny
So on our colder days where I might be starting the car with 35-40*F temps, will a 10w30 flow as fast as 5w30? Is there enough difference between them to make a difference?
Theoretically, the 5W should flow better since that is technically purpose of a lower viscosity multigrade. I do however have an extension to Shiny's question for the rest of you BITOGers; at what (regular) cold start temperatures would it be beneficial to actually start using a lower first digit weight oil? (i.e. 0w30/5w30 instead of 10w30)
 
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472
Location
Hampshire, UK
In theory it should all go inline with the temperature of the corresponding Cold Cranking Simulator (CCS) test which defines the minimum temperature for turning the engine crackshaft over. This reads as. for 10WXX, -25C for 5WXX, -30C for 0WXX, -35C There's another test called the Mini-Rotary Viscometer (MRV) test that also gets run on oils. This always gets run at 10C below the corresponding CCS temperature, the idea being that the oil will NOT be gellified into a waxy solid at or above this temperature.
 
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43,651
Location
'Stralia
Re the last two posts, the "W" rating is what happens at the extreme cold end of a lubricant's performance envelope, there's a myth on BITOG that a "0W" will always flow better than a 10W at any temperature, which plain and simple isn't true. Here's results from a series of engine tests, which shows the establishment of full oil pressure (FOPT), and oil flow from the rocker arms (RAOT, Rocker Arm Oiling Time) with different viscosities under different temperatures. Take the SAE30 at 20F, 15 seconds to RAOT, 6 to FOPT. the 10W30 at 9F (11 and 6) and the 5W20 at -11F...they are similar times, offset by temperature commensurate with the "W" rating, or lack of it. The SAE 30 at 30F shows what the engine was capable of achieving with full flowing oil...3 seconds to RAOT, and 6 to full oil pressure. The 5W does the same at 12 F. If you increase the ambient to 50F, none of the oils are going to beat 3 and 6, the mechanical design of the engine will only move SO much oil through the air filled galleries, so the myth that a 0W at 100F will provide better flow than an SAE30 is just a myth. Me personally, in Oz, have a current favourite viscosity grade, 5W30 A3/B4, which will do me anywhere in the country (I'd prefer a 10W30, but all of those are semis, and don't carry much of a cost reduction over the full synths). OP, in pheonix, M1 10W30 would be great. To extend on the "W" part, and it's extreme cold performance, it IS important to starting. There's a bunch of SAE papers that you can find on cold starting performance. This one is good, as it's the limits of cold starting temperature for a range of engines, on a range of oils. Note with interest: * the 25W30 has a higher no start temperature than 20W50...demonstrating what the "W" means * Similarly, the 0W, 5W, and 10W 30s indicate that in the OP's Pheonix, none of them hold an advantage in his ambient...the 25W would do if you wanted (I've run 25W70 to -7 or 8 C). * The 4.0 straight 6 (I think it's Jeep) struggles at temperatures quite a way higher than the broad band of engines.
 
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43,651
Location
'Stralia
re Joe's comment, here's another. You can see that the 10W30 holds a 7C (13F) advantage over the 20W, both for free pumping, and for accetpable and borderline pumping. Take the 10W or the 20W to 0C, and the results will be the same as each other. Another indicative series of engine starting tests, demonstrating that the "W" rating is simply offsetting cold performance, this time in terms of startability, where the residual film of oil on the bearings may restrict cranking speed. When you see tests like "CCS", it's the "Cold Cranking Simulator", to try to provide performance envelopes for that parameter.
 

pbm

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8,815
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New York
Joe90: Welcome to BITOG...it's great to have another knowledgeable member. I have a simple question: Is there really much difference between a 5w20 and a 5w30 (both dinos) at the winter temps that I normally see...0*F being about the coldest with the teens being the norm?
 

OVERKILL

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44,804
Location
Ontario, Canada
Originally Posted By: Joe90_guy
In theory it should all go inline with the temperature of the corresponding Cold Cranking Simulator (CCS) test which defines the minimum temperature for turning the engine crackshaft over. This reads as. for 10WXX, -25C for 5WXX, -30C for 0WXX, -35C There's another test called the Mini-Rotary Viscometer (MRV) test that also gets run on oils. This always gets run at 10C below the corresponding CCS temperature, the idea being that the oil will NOT be gellified into a waxy solid at or above this temperature.
It's 5C below the CCS temp; CCS @ -35C, MRV @ -40C smile And yes, the MRV test is designed to replicate the ability for the oil to pump and it has a much higher limit on viscosity than CCS.
 
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28,129
Location
Regina, Saskatchewan, Canada
Originally Posted By: pbm
I have a simple question: Is there really much difference between a 5w20 and a 5w30 (both dinos) at the winter temps that I normally see...0*F being about the coldest with the teens being the norm?
Usually, a 5w-20 will have better cold numbers than a 5w-30. But, the difference isn't much more than splitting hairs.
 
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65
Location
Ca
While a 5-30 is fine for 0F, that's cold enough where I would want to use the 5-20 for its better cold flow. Even more so if you do lots of short trips. Less important if you're starting once or twice a day and driving a few hours at a time.
 
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124
Location
Tx
So, a 10w30 only takes six seconds to reach normal operating viscosity when started at 9*f? That's relatively quick. If that isn't the case however, I would really like to know those numbers.
 
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17,501
Location
Clovis, CA
<span style="font-family: 'Arial'">If you think 10W-30 is too thick in Arizona, pour some of that oil in a clear glass jar and take it outside. Shake the jar around a little bit. Does the oil slosh around freely? If the answer is yes, then that is the correct viscosity for your vehicle.</span>
 
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43,651
Location
'Stralia
Originally Posted By: Luisraul924
So, a 10w30 only takes six seconds to reach normal operating viscosity when started at 9*f? That's relatively quick. If that isn't the case however, I would really like to know those numbers.
No, it was how long it took to flow to the remote areas of the galleries on start-up at whatever ambient temperature, and build full oil pressure...it's all the "increased wear" that is discussed on the site that isn't there until the oil doesn't pump. How long oil takes to warm up is obviously longer than 6 seconds.
 
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472
Location
Hampshire, UK
You're right of course. Think the brain has started to atrophy since leaving work. In my (admittedly pathetic) defence, there WAS a time when the difference between CCS and MRV was 10C. The SAE in their infinite wisdom restricted the CCS limits (around 2002?) and the difference drop to 5C.
 
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28,129
Location
Regina, Saskatchewan, Canada
Originally Posted By: Merkava_4
If you think 10W-30 is too thick in Arizona, pour some of that oil in a clear glass jar and take it outside. Shake the jar around a little bit. Does the oil slosh around freely? If the answer is yes, then that is the correct viscosity for your vehicle.
A 0w-20 would slosh around freely there, too, Merk. I know ILSAC testing is called weak, but yours is a little much. wink
Originally Posted By: Joe09_guy
Think the brain has started to atrophy since leaving work.
Don't worry. There are plenty of old SAE J300 tables floating around here all the time. wink
 
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