Given the same conditions will xxW-20 or xxW-30 or xxW-40 get up to the operating temperature faster?
Which oil gets up to the operating temperature faster??
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I thought that the lower viscosity oil reaches operating temp quicker however the higher viscosity will run at a higher operating temperature.
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Some have suggested that with heavier weights, the added load generates more thermal input.
It's apparently proven that heavier oils generate more "self created" heat due to shearing (although I probably didn't say it correctly). I think that this is probably trumped by external btu throughput, though.
lighter weights are assumed to be more thermally conductive ..but that also means that they more easily reject heat.
I would think that lighter oil would react to changes quicker ..but I don't quite see it being any different in average temp. I see heavier oil being more "dampened".
It's apparently proven that heavier oils generate more "self created" heat due to shearing (although I probably didn't say it correctly). I think that this is probably trumped by external btu throughput, though.
lighter weights are assumed to be more thermally conductive ..but that also means that they more easily reject heat.
I would think that lighter oil would react to changes quicker ..but I don't quite see it being any different in average temp. I see heavier oil being more "dampened".
Higher viscosity means more power required= more gas & wear= faster warmup.
My opinion:
An engine will get up to operating temperature faster with a thicker oil because the oil doesn't absorb as much heat as quickly. So, the enigne is warmer faster because the oil isn't absorbing the heat. As the engine gets warmer, the oil will absorb more heat, but not as fast as thinner oil.
A thinner oil will absorb more heat quicker, not allowing the engine to get up to temp as quickly.
So, I think the answer to this question would depend on many variables. Engine, oil capacity, volume of oil being pumped, load on the engine, etc... One engine may get the oil up to temp quicker with a thin oil while another may get the oil up to temp quicker with a thicker oil.
Just my 2 cents.
An engine will get up to operating temperature faster with a thicker oil because the oil doesn't absorb as much heat as quickly. So, the enigne is warmer faster because the oil isn't absorbing the heat. As the engine gets warmer, the oil will absorb more heat, but not as fast as thinner oil.
A thinner oil will absorb more heat quicker, not allowing the engine to get up to temp as quickly.
So, I think the answer to this question would depend on many variables. Engine, oil capacity, volume of oil being pumped, load on the engine, etc... One engine may get the oil up to temp quicker with a thin oil while another may get the oil up to temp quicker with a thicker oil.
Just my 2 cents.
It is my belief and I sure could be wrong that lighter oil heat up faster/transfer heat faster than heavier oils. This is another reason I was informed for Honda/Ford and others going to the lighter wts as the engine warms up faster and the pollution controls work faster. Polluttion devices do not work well in a cold engine.
That is why the oxygenated enriched gas is mostly mandated in the winter.
Craig
That is why the oxygenated enriched gas is mostly mandated in the winter.
Craig
Craig, you are on to something, this along with reduced water jacket surface on the heads encourages quicker warmup and is one of the keys to meeting LEV and ULEV emissions standards.
Most oils have about the same density and specific heat so they will all have approximately the same heat capacity regardless of the viscosity.
If the oil is thinner and is moving faster (see my later chapters) then the result will be cooler metal parts. This is a function of the faster moving thinner oil. If the oil moves faster it will cool the parts more than a thicker oil moving slower. If the oil is moving faster it will actually pick up less heat per cc of oil and therefore the thinner, faster moving oil will actually heat up to a lesser temperature than a thicker, slower moving oil. Net result: the thinner, faster moving oil will not get as hot and the engine will run cooler. Less heat in the oil will make it last longer and actually make it run a little thicker than it’s specifications may otherwise indicate. And the decrease in metal temperatures will itself result in less wear and tear.
There are many things happening here and I find the concept is difficult for many people.
Whether the oil in your specific engine heats up (from a cold start-up) slower or faster is multi-factorial.
aehaas
If the oil is thinner and is moving faster (see my later chapters) then the result will be cooler metal parts. This is a function of the faster moving thinner oil. If the oil moves faster it will cool the parts more than a thicker oil moving slower. If the oil is moving faster it will actually pick up less heat per cc of oil and therefore the thinner, faster moving oil will actually heat up to a lesser temperature than a thicker, slower moving oil. Net result: the thinner, faster moving oil will not get as hot and the engine will run cooler. Less heat in the oil will make it last longer and actually make it run a little thicker than it’s specifications may otherwise indicate. And the decrease in metal temperatures will itself result in less wear and tear.
There are many things happening here and I find the concept is difficult for many people.
Whether the oil in your specific engine heats up (from a cold start-up) slower or faster is multi-factorial.
aehaas
Please explain how the faster moving oil cools the parts more if it picks up less heat. The only way oil cools is that it "picks up" (absorbs) heat from the metal it comes in contact with. If it absorbs less heat, then the metal stays hotter. It's the same reason some engines will run hotter if you take the thermostat out completely. The coolant flows through the engine so much more rapidly that it doesn't remain in contact with the critical hot spots (cylinder walls and exhaust port areas of the head) to adequately remove the heat.
Granted, thinner oils do run cooler, but it's because of less internal friction from viscous drag.
I don't know but In general Chemistry, the more intermolecular forces you have in a fluid ( oil ) , the more viscocity it has. That means in order to excite all the molecules and molecular forces ( London forces in the case of oil , it means you need to apply more heat )
so going theoretically, the higher the viscocity, the faster it will get to temp.
so going theoretically, the higher the viscocity, the faster it will get to temp.
I believe the thinner oil will be more uniform in temp than the thicker oil. The thicker oil will run a little hotter, as well, as it doesn't get rid of the heat as well.
A lot of engine cooling is from the oil.
A lot of engine cooling is from the oil.
Hmm conclusion I get from your replys is that thicker oil will get up to the operating temperature faster then thinner oil given the same conditions but with thinner oil engine will run cooler at operating temperature given the same conditions then with thicker oil.
The reason I am asking this is because most of us drive rather short trips on daily basis and we rarly actually get the oil up to the operating temperature.
I would think you want your oil to get up to the operating temperature ad fast as possible...
For example I drive to work 16 miles each way. First 3-4 miles of that are city and then 12-13 miles of highway driving at about 65-75mph.
This morning it took 9 miles for my oil to get up to the operating temperature(and this morning it was 70F, I wonder how long it takes when it is 20F outside). So more then half of my trip I was driving with thicker oil then what is my engine designed for..I also wonder if wear is higher during this period compared to when the oil is up to the operating temp?
The reason I am asking this is because most of us drive rather short trips on daily basis and we rarly actually get the oil up to the operating temperature.
I would think you want your oil to get up to the operating temperature ad fast as possible...
For example I drive to work 16 miles each way. First 3-4 miles of that are city and then 12-13 miles of highway driving at about 65-75mph.
This morning it took 9 miles for my oil to get up to the operating temperature(and this morning it was 70F, I wonder how long it takes when it is 20F outside). So more then half of my trip I was driving with thicker oil then what is my engine designed for..I also wonder if wear is higher during this period compared to when the oil is up to the operating temp?
All things being equal, an oil with a higher viscosity will allow the engine to reach normal operating temperature quicker than an oil of a lower viscosity. Probably due to the greater amount of work required.
I've witnessed this using everything from 5-30 to 10-60 in the same engine. A side benefit to higher viscosity oils IMO...especially at colder temps...a faster warmup is always welcome.
I've witnessed this using everything from 5-30 to 10-60 in the same engine. A side benefit to higher viscosity oils IMO...especially at colder temps...a faster warmup is always welcome.
on my 91 pathfinder V6 I've been using 5w30 amsoil and when I treated it with ARX and 5w30 dino oil I noticed the water temp went up faster, and I would get warm air coming from the vent almost right away after starting the truck this was during the cold months.
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I'll buy this for initial ..or some "static" btu production, but this surely has to be massively stepped on by the btu's passing though the oil from contact with cylinder walls and pistons.
That is, sure a 50 weight (which may be above a 70 weight at start up temp) is going to do its little dity with its shear resistance to motion when compared to a 20 weight (which may be a high 30 or 40 weight at start up). It's also going to require more hp to pump, adding more btu's per minute.. But that's gotta be nothing compared to what the engine is hammering into it on a continuous basis. Otherwise you would always see higher oil temps, after warm up, with heavier oil.
In my limited observations, I noticed heavier oil coming up quicker in oil temp, but didn't see any higher oil temps. The pressure was the sliding variable, IIRC. Naturally this has limits if you go too far in one direction or another ..but the envelope has lots of room ..as long as you don't head into grenade territory.
Many people here seem to be confusing the question "what oil gets warmer quicker?" with "what oil will let my engine get warmer quicker?"
Just because your heater starts blowing warm air doesn't mean that all 5 quarts of oil are up to operating temp. In fact, it tells me that the oil may not be absobing as much heat, allowing the coolant to absorb more heat.
Just because your heater starts blowing warm air doesn't mean that all 5 quarts of oil are up to operating temp. In fact, it tells me that the oil may not be absobing as much heat, allowing the coolant to absorb more heat.
Medic,
You are on to something. Most people are confusing their temp guage for their coolant with that of the oil. Just because your engine is up to temperature doesn't mean your oil is. Actually, your engine does not have the same temperature all over it. At the oil pan, I would assume the engine is the coldest, while in the heads it is the hottest.
Your temp guage is reading the coolant temperature. It is also reading it at one point in the cooling system. You will find that the coolant varies in temperature based on where it is in the system.
I've heard, but not totally sure, that most oils get to operating temperature about 20 minutes into your drive.
You are on to something. Most people are confusing their temp guage for their coolant with that of the oil. Just because your engine is up to temperature doesn't mean your oil is. Actually, your engine does not have the same temperature all over it. At the oil pan, I would assume the engine is the coldest, while in the heads it is the hottest.
Your temp guage is reading the coolant temperature. It is also reading it at one point in the cooling system. You will find that the coolant varies in temperature based on where it is in the system.
I've heard, but not totally sure, that most oils get to operating temperature about 20 minutes into your drive.
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