20w-50
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Joined: Jan 2005
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From: East Bay area (by SF) Ca
Is oil really the lifeblood of an engine? That's a long-popular analogy, but it's really not an accurate description. Blood carries nutrients to cells, but it's air that carries fuel--the "nutrition"--for an engine. However, without oil to lubricate and cool moving parts, keep them clean and help to seal the pistons in the cylinders, the engine would run for only a matter of seconds--then sieze. So, yes, oil is important.
Oil is so important that we want no less than the best the engine can get--for a good low price, of course. Now, what if you could custom-blend the oil so it had exactly the characteristics you believe that your vehicle needs for the type of driving you do?
Sounds pretty neat, and we were given the opportunity to do just that at the Valvoline lab in Lexington, Ky. When we were finished, we had an oil we thought would be just right for upcoming summer weather in short-trip driving around the New York City area.
That was our one shot at playing lubricant scientist, but the experience produced only enough oil for a top-up. So at the next oil change, we'll have to pick from an off-the-shelf assortment--like everyone else. But we think we'll do a better job of selection now, thanks to a short course in engine oil blending from Valvoline Technical Director Thomas Smith. Here's what we learned.
Viscosity
Viscosity (a fluid's resistance to flow) is rated at 0° F (represented by the number preceding the "W" [for Winter]) and at 212° F (represented by the second number in the viscosity designation). So 10W-30 oil has less viscosity when cold and hot than does 20W-50. Motor oil thins as it heats and thickens as it cools. So, with the right additives to help it resist thinning too much, an oil can be rated for one viscosity when cold, another when hot. The more resistant it is to thinning, the higher the second number (10W-40 versus 10W-30, for example) and that's good. Within reason, thicker oil generally seals better and maintains a better film of lubrication between moving parts.
At the low-temperature end, oil has to be resistant to thickening so that it flows more easily to all the moving parts in your engine. Also, if the oil is too thick the engine requires more energy to turn the crankshaft, which is partly submerged in a bath of oil. Excessive thickness can make it harder to start the engine, which reduces fuel economy. A 5W oil is typically what's recommended for winter use. However, synthetic oils can be formulated to flow even more easily when cold, so they are able to pass tests that meet the 0W rating.
Once the engine is running, the oil heats up. The second number in the viscosity rating--the "40" in 10W-40, for example--tells you that the oil will stay thicker at high temperatures than one with a lower second number--the "30" in 10W-30, for example. What's really important is that you use the oil viscosity your car's owner's manual recommends.
Why So Many Oils?
Look on the shelves in auto parts stores and you'll see oils labeled for all kinds of specific purposes: high-tech engines, new cars, higher-mileage vehicles, heavy-duty/off-road SUVs. In addition, you'll see a wide selection of viscosities. If you read your owner's manual, you'll know what the car manufacturer recommends for a brand-new vehicle. The manual may include a reference to Energy Conserving oils, which simply means that the oil has passed a lab test against a reference oil. It's no guarantee of better fuel economy, but most of the leading brands have at least some viscosities that are so labeled. Let's take a look at the different types.
Premium Conventional Oil. This is the standard new-car oil. All leading brands have one for service level SL, available in several viscosities. The carmakers usually specify a 5W-20 or 5W-30 oil, particularly for lower temperatures, with a 10W-30 oil as optional, particularly for higher ambient temperatures. These three ratings cover just about every light-duty vehicle on the road. Even more important, though, is changing the oil and filter regularly. A 4000 miles/4 months interval is good practice. The absolute minimum is twice a year. If your car has an electronic oil-change indicator on the instrument cluster, don't exceed its warning.
Full Synthetic Oil. The oils made for high-tech engines, whether in a Chevy Corvette or Mercedes-Benz, are full synthetics. If these oils pass stringent special tests (indicated by their labeling), it means they have superior, longer-lasting performance in all the critical areas, from viscosity index to protection against deposits. They flow better at low temperatures and maintain peak lubricity at high temperatures. So why shouldn't everyone use them? Answer: These oils are expensive and not every engine needs them. In fact, there may be some features that your car's engine needs that the synthetics don't have. Again, follow your owner's manual.
Synthetic Blend Oil. These have a dose of synthetic oil mixed with organic oil, and overall are formulated to provide protection for somewhat heavier loads and high temperatures. This generally means they're less volatile, so they evaporate far less, which reduces oil loss (and increases fuel economy). They're popular with drivers of pickups/SUVs who want the high-load protection. And they're a lot less expensive than full synthetics, maybe just pennies more than a premium conventional oil.
Higher Mileage Oil. Today's vehicles last longer, and if you like the idea of paying off the car and running the mileage well into six figures, you have another oil choice, those formulated for higher-mileage vehicles. Almost two-thirds of the vehicles on the road have more than 75,000 miles on the odometer. So the oil refiners have identified this as an area of customer interest, and have new oils they're recommending for these vehicles.
When your car or light truck/SUV is somewhat older and has considerably more mileage, you may notice a few oil stains on the garage floor. It's about this time that you need to add a quart more often than when the vehicle was new. Crankshaft seals may have hardened and lost their flexibility, so they leak (particularly at low temperatures) and may crack. The higher-mileage oils are formulated with seal conditioners that flow into the pores of the seals to restore their shape and increase their flexibility. In most cases, rubber seals are designed to swell just enough to stop leaks. But the oil refiners pick their "reswelling" ingredients carefully. Valvoline showed us the performance data of one good seal conditioner that swelled most seal materials, but actually reduced swelling of one type that tended to swell excessively from the ingredients found in some other engine oils.
You also may have noticed some loss of performance and engine smoothness as a result of engine wear on your higher-mileage vehicle. These higher-mileage oils also have somewhat higher viscosities. (Even if the numbers on the container don't indicate it, there's a fairly wide range for each viscosity rating and the higher-mileage oils sit at the top of each range.) They also may have more viscosity-index improvers in them. The result? They seal piston-to-cylinder clearances better, and won't squeeze out as readily from the larger engine bearing clearances. They also may have a higher dose of antiwear additives to try to slow the wear process.
If you have an older vehicle, all of these features may mean more to you than what you might get from a full synthetic, and at a fraction the price.
Beyond that, there's plenty more to the oil story. Read on.
Oil is so important that we want no less than the best the engine can get--for a good low price, of course. Now, what if you could custom-blend the oil so it had exactly the characteristics you believe that your vehicle needs for the type of driving you do?
Sounds pretty neat, and we were given the opportunity to do just that at the Valvoline lab in Lexington, Ky. When we were finished, we had an oil we thought would be just right for upcoming summer weather in short-trip driving around the New York City area.
That was our one shot at playing lubricant scientist, but the experience produced only enough oil for a top-up. So at the next oil change, we'll have to pick from an off-the-shelf assortment--like everyone else. But we think we'll do a better job of selection now, thanks to a short course in engine oil blending from Valvoline Technical Director Thomas Smith. Here's what we learned.
Viscosity
Viscosity (a fluid's resistance to flow) is rated at 0° F (represented by the number preceding the "W" [for Winter]) and at 212° F (represented by the second number in the viscosity designation). So 10W-30 oil has less viscosity when cold and hot than does 20W-50. Motor oil thins as it heats and thickens as it cools. So, with the right additives to help it resist thinning too much, an oil can be rated for one viscosity when cold, another when hot. The more resistant it is to thinning, the higher the second number (10W-40 versus 10W-30, for example) and that's good. Within reason, thicker oil generally seals better and maintains a better film of lubrication between moving parts.
At the low-temperature end, oil has to be resistant to thickening so that it flows more easily to all the moving parts in your engine. Also, if the oil is too thick the engine requires more energy to turn the crankshaft, which is partly submerged in a bath of oil. Excessive thickness can make it harder to start the engine, which reduces fuel economy. A 5W oil is typically what's recommended for winter use. However, synthetic oils can be formulated to flow even more easily when cold, so they are able to pass tests that meet the 0W rating.
Once the engine is running, the oil heats up. The second number in the viscosity rating--the "40" in 10W-40, for example--tells you that the oil will stay thicker at high temperatures than one with a lower second number--the "30" in 10W-30, for example. What's really important is that you use the oil viscosity your car's owner's manual recommends.
Why So Many Oils?
Look on the shelves in auto parts stores and you'll see oils labeled for all kinds of specific purposes: high-tech engines, new cars, higher-mileage vehicles, heavy-duty/off-road SUVs. In addition, you'll see a wide selection of viscosities. If you read your owner's manual, you'll know what the car manufacturer recommends for a brand-new vehicle. The manual may include a reference to Energy Conserving oils, which simply means that the oil has passed a lab test against a reference oil. It's no guarantee of better fuel economy, but most of the leading brands have at least some viscosities that are so labeled. Let's take a look at the different types.
Premium Conventional Oil. This is the standard new-car oil. All leading brands have one for service level SL, available in several viscosities. The carmakers usually specify a 5W-20 or 5W-30 oil, particularly for lower temperatures, with a 10W-30 oil as optional, particularly for higher ambient temperatures. These three ratings cover just about every light-duty vehicle on the road. Even more important, though, is changing the oil and filter regularly. A 4000 miles/4 months interval is good practice. The absolute minimum is twice a year. If your car has an electronic oil-change indicator on the instrument cluster, don't exceed its warning.
Full Synthetic Oil. The oils made for high-tech engines, whether in a Chevy Corvette or Mercedes-Benz, are full synthetics. If these oils pass stringent special tests (indicated by their labeling), it means they have superior, longer-lasting performance in all the critical areas, from viscosity index to protection against deposits. They flow better at low temperatures and maintain peak lubricity at high temperatures. So why shouldn't everyone use them? Answer: These oils are expensive and not every engine needs them. In fact, there may be some features that your car's engine needs that the synthetics don't have. Again, follow your owner's manual.
Synthetic Blend Oil. These have a dose of synthetic oil mixed with organic oil, and overall are formulated to provide protection for somewhat heavier loads and high temperatures. This generally means they're less volatile, so they evaporate far less, which reduces oil loss (and increases fuel economy). They're popular with drivers of pickups/SUVs who want the high-load protection. And they're a lot less expensive than full synthetics, maybe just pennies more than a premium conventional oil.
Higher Mileage Oil. Today's vehicles last longer, and if you like the idea of paying off the car and running the mileage well into six figures, you have another oil choice, those formulated for higher-mileage vehicles. Almost two-thirds of the vehicles on the road have more than 75,000 miles on the odometer. So the oil refiners have identified this as an area of customer interest, and have new oils they're recommending for these vehicles.
When your car or light truck/SUV is somewhat older and has considerably more mileage, you may notice a few oil stains on the garage floor. It's about this time that you need to add a quart more often than when the vehicle was new. Crankshaft seals may have hardened and lost their flexibility, so they leak (particularly at low temperatures) and may crack. The higher-mileage oils are formulated with seal conditioners that flow into the pores of the seals to restore their shape and increase their flexibility. In most cases, rubber seals are designed to swell just enough to stop leaks. But the oil refiners pick their "reswelling" ingredients carefully. Valvoline showed us the performance data of one good seal conditioner that swelled most seal materials, but actually reduced swelling of one type that tended to swell excessively from the ingredients found in some other engine oils.
You also may have noticed some loss of performance and engine smoothness as a result of engine wear on your higher-mileage vehicle. These higher-mileage oils also have somewhat higher viscosities. (Even if the numbers on the container don't indicate it, there's a fairly wide range for each viscosity rating and the higher-mileage oils sit at the top of each range.) They also may have more viscosity-index improvers in them. The result? They seal piston-to-cylinder clearances better, and won't squeeze out as readily from the larger engine bearing clearances. They also may have a higher dose of antiwear additives to try to slow the wear process.
If you have an older vehicle, all of these features may mean more to you than what you might get from a full synthetic, and at a fraction the price.
Beyond that, there's plenty more to the oil story. Read on.
Senior Member
Joined: Jul 2004
Posts: 6,200
Likes: 39
From: Easton, Pa.
The last number of the weight designation is the base weight of the oil.
The first number is how the formulation acts at colder temperatures.
As the temperature in the engine heats up the combination formulated into the specific weight grade is held more even in viscosity.
Said another way, the 5# means it stays thinner at colder temperatures.
As the engine heats and causes the oil viscosity to lower the effect is to keep the weight more near even or pegged to the 10 weight.
This is how the 5# helps cold start turn over and faster travel to all areas of the engine while the 10# tends to limit how thin the oil becomes at operating temp.
All this within reasonable milage use limit before the oil picks up contamination and the effects of the 5# formulation goes away. This formulation does not last beyond a certain amount of use time before the effects are degraded and become useless.
Those that try to run oils for very long peroids of time thinking there super filter is the saving grace, lose the formulation weight advantage long before they change there oil.
Reason is the polymers are distroyed in a relativly short time by heat and shearing forces that take place at all the bearings and all rubbing surfaces within the engine.
Changing oil at short intervals ensures you keep ahead of these actions.
Synthetic based lubes do delay and lengthen out the oils ability to resist the effects of heat.
The Motorcraft 5w20 "blend" would seem to be the better of all these atributes at the present time for wear rates, wide range performance and cost.
The first number is how the formulation acts at colder temperatures.
As the temperature in the engine heats up the combination formulated into the specific weight grade is held more even in viscosity.
Said another way, the 5# means it stays thinner at colder temperatures.
As the engine heats and causes the oil viscosity to lower the effect is to keep the weight more near even or pegged to the 10 weight.
This is how the 5# helps cold start turn over and faster travel to all areas of the engine while the 10# tends to limit how thin the oil becomes at operating temp.
All this within reasonable milage use limit before the oil picks up contamination and the effects of the 5# formulation goes away. This formulation does not last beyond a certain amount of use time before the effects are degraded and become useless.
Those that try to run oils for very long peroids of time thinking there super filter is the saving grace, lose the formulation weight advantage long before they change there oil.
Reason is the polymers are distroyed in a relativly short time by heat and shearing forces that take place at all the bearings and all rubbing surfaces within the engine.
Changing oil at short intervals ensures you keep ahead of these actions.
Synthetic based lubes do delay and lengthen out the oils ability to resist the effects of heat.
The Motorcraft 5w20 "blend" would seem to be the better of all these atributes at the present time for wear rates, wide range performance and cost.
Last edited by Bluegrass; Jan 19, 2005 at 01:21 PM.
Junior Member
Joined: Jan 2005
Posts: 4
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From: Biloxi, Mississippi
I use 10w30 Castrol GTX... Thats what the 5.0 has ran on since I can remember. I live in Mississippi, the coast... its warm here usually, infact, it didnt get cold this year until the end of December... sleeted on Christmas day, the next I was sweating again.
Anyway, this is my first post. I had to put my two cents in on this one. Here they are:
Why the hell are ya'll arguing over oil.... wouldn't that time be better spent ******* on the Chevy sites??
Anyway, this is my first post. I had to put my two cents in on this one. Here they are:
Why the hell are ya'll arguing over oil.... wouldn't that time be better spent ******* on the Chevy sites??
Banned
Joined: Jan 2005
Posts: 202
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From: East Bay area (by SF) Ca
Originally posted by 95MarkIII5.0L
Why the hell are ya'll arguing over oil.... wouldn't that time be better spent ******* on the Chevy sites??
Why the hell are ya'll arguing over oil.... wouldn't that time be better spent ******* on the Chevy sites??
been a chevy man all my life... i just gotta say though, fords do sound better, and they have a more modern look to em 
plus i got my 1997 F150 Lariat with only 49k miles on it for less than most would pay for an 89 mustang..... bone stock lol
Senior Member
Joined: Jul 2004
Posts: 6,200
Likes: 39
From: Easton, Pa.
Just for the record, I don't consider my reply an argument but an offer of a view that has not been put forth.
I personally could give a rats *** what anyone uses, if real position matters.
If someone wants to use 40 weight or some other lube, then comes on these boards and complains about starting in cold weather, then they get what they deserve.
I personally could give a rats *** what anyone uses, if real position matters.
If someone wants to use 40 weight or some other lube, then comes on these boards and complains about starting in cold weather, then they get what they deserve.
Banned
Joined: Jan 2005
Posts: 202
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From: East Bay area (by SF) Ca
Chill out bluegrass lol i think one thing that has to be taken into consideration, is that people here live in all different climates... like where i live, the temp rarely goes below 30 - 40 degrees... even now in the winter... so for you guys who cant step outside with anything less than a snow parka, yeah... lightweight oil is really good... but for us? especially on those summer days... whew... 110 degrees will eat up 5w30 like water..
Thread Starter
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Senior Member
Joined: Jan 2005
Posts: 255
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From: Camas Valley,Oregon
Well maybe i should go with different oil. I'm not sure but i had a thin oil like 10-30 or somthing like that in it. It had a very bad tap that just started out of the blue and yes it had oil in the motor. So i was recommended by a friend of mine that builds high performance big blocks some thicker oil and was told that will work very well. so sure enough i give it the oil change with some 15-50 or 20-50 and now the engine sounds great and havent heard a noice sense.
Senior Member
Joined: May 2001
Posts: 1,080
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From: Maryland
Well aren't these oil threads fun!
I want to let you guys know that I now work for one of the oldest motor oil manufacturers in the USA (86 years) the company is also the oldest constantly running oil testing lab, only the military and railroads have been testing longer than we have.
I will not give the name here because I am not allowed (Yet) but what I am getting to, is that I can dispell all the myths about oil. we have a full technical staff at my disposal. some of which have been in the oil making business for over 20 years.
So I will ask them any question for you if I don't know the answer already. And in most cases I can published documentation on the answers.
now to the thread at hand, I will ask tomorrow about the "W" and weights. However, I am pretty sure that the first number is the base weight of the oil (Not the second number) and no matter how much the oil breaks down it will end up at the first number.
more later-
I want to let you guys know that I now work for one of the oldest motor oil manufacturers in the USA (86 years) the company is also the oldest constantly running oil testing lab, only the military and railroads have been testing longer than we have.
I will not give the name here because I am not allowed (Yet) but what I am getting to, is that I can dispell all the myths about oil. we have a full technical staff at my disposal. some of which have been in the oil making business for over 20 years.
So I will ask them any question for you if I don't know the answer already. And in most cases I can published documentation on the answers.
now to the thread at hand, I will ask tomorrow about the "W" and weights. However, I am pretty sure that the first number is the base weight of the oil (Not the second number) and no matter how much the oil breaks down it will end up at the first number.
more later-
Banned
Joined: Jan 2005
Posts: 202
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From: East Bay area (by SF) Ca
Valvoline
Viscosity
Viscosity (a fluid's resistance to flow) is rated at 0° F (represented by the number preceding the "W" [for Winter]) and at 212° F (represented by the second number in the viscosity designation). So 10W-30 oil has less viscosity when cold and hot than does 20W-50. Motor oil thins as it heats and thickens as it cools. So, with the right additives to help it resist thinning too much, an oil can be rated for one viscosity when cold, another when hot. The more resistant it is to thinning, the higher the second number (10W-40 versus 10W-30, for example) and that's good. Within reason, thicker oil generally seals better and maintains a better film of lubrication between moving parts.
Viscosity
Viscosity (a fluid's resistance to flow) is rated at 0° F (represented by the number preceding the "W" [for Winter]) and at 212° F (represented by the second number in the viscosity designation). So 10W-30 oil has less viscosity when cold and hot than does 20W-50. Motor oil thins as it heats and thickens as it cools. So, with the right additives to help it resist thinning too much, an oil can be rated for one viscosity when cold, another when hot. The more resistant it is to thinning, the higher the second number (10W-40 versus 10W-30, for example) and that's good. Within reason, thicker oil generally seals better and maintains a better film of lubrication between moving parts.
Banned
Joined: Jan 2005
Posts: 202
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From: East Bay area (by SF) Ca
if you ask me, the numbers are purely characteristics... im sure there is a higher definition, but by reading that book i posted up there from valvoline, i get this:
Bare basics: 10w30 = an oil that reacts like a 10 weight in the winter, and a 30 weight in the summer.
same with any oil... its a crossbreed... instead of just using 40 weight.. or 30 weight, you can have an oil that uses two different viscocities in different temperatures.... forget the original number, just remember that the second number is always going to be the thickest of the two, and relating to summer driving conditions... so a 50 weight is really good for higher mileage motors during the summer, but a 20 weight will suffice for cold winters... so you use 20w50... its like the oil has a switch somewhere in the molecules that changes itself to the weather... can someone verify this? and yes i know, its all purely laymens terms, but you get the picture..
Bare basics: 10w30 = an oil that reacts like a 10 weight in the winter, and a 30 weight in the summer.
same with any oil... its a crossbreed... instead of just using 40 weight.. or 30 weight, you can have an oil that uses two different viscocities in different temperatures.... forget the original number, just remember that the second number is always going to be the thickest of the two, and relating to summer driving conditions... so a 50 weight is really good for higher mileage motors during the summer, but a 20 weight will suffice for cold winters... so you use 20w50... its like the oil has a switch somewhere in the molecules that changes itself to the weather... can someone verify this? and yes i know, its all purely laymens terms, but you get the picture..
Senior Member
Joined: May 2001
Posts: 1,080
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From: Maryland
it is not winter and summer.
it is cold start up weight and the second number in a multi visc oil is the weight Characteristics at full operating temp. (Laymens terms)
so when you first start the engine in the morning whether it is summer or winter the weight of the oil is the first number. so a 20w-50 is an absolutely horrible thing to have in an engine that calls for a 5w-xx . then once the engine is up to full operating temp you get the second number (Atleast until the modifiers break down) so again the 20w-50 is a horrible choice for these tight tolerance engines. the 50 at operating temp will cause a lot of drag on the internal parts and cause the engine to run at a lower efficiency. (Laymens terms)
more laymens terms: all oils start out as one weight. addatives/modifiers are then mixed with the base oil to get the desired multi viscosity oil
it is cold start up weight and the second number in a multi visc oil is the weight Characteristics at full operating temp. (Laymens terms)
so when you first start the engine in the morning whether it is summer or winter the weight of the oil is the first number. so a 20w-50 is an absolutely horrible thing to have in an engine that calls for a 5w-xx . then once the engine is up to full operating temp you get the second number (Atleast until the modifiers break down) so again the 20w-50 is a horrible choice for these tight tolerance engines. the 50 at operating temp will cause a lot of drag on the internal parts and cause the engine to run at a lower efficiency. (Laymens terms)
more laymens terms: all oils start out as one weight. addatives/modifiers are then mixed with the base oil to get the desired multi viscosity oil
Banned
Joined: Jan 2005
Posts: 202
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From: East Bay area (by SF) Ca
i knew that the differences were between cold and warm operating temps, but like i said... laymens... in 110 degree weather, the motor even on a "cold start" is not going to leave the oil anywhere near the same thickness of below 20 degree weather... so what i meant by that was, at cold temps (whether that be due to below 0 temps, or "cold" starts on a warm day) the 1st number is the weight of the oil...
Member
Joined: Apr 2002
Posts: 39
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From: Moorefield, West Virginia
OK, forget all the talk. There is no reason to use anything other than the recommended oil. That is why it is recommended, it is what is best for that particular engine. If you want to go one number lower for winter and one number higher for summer, you are probably ok. But a 40 or 50 viscosity oil is just going to kill your engine over time.