Oil....Is This True ?

[Tommy Gun]

A quote from another site :innocent:



I agree that with synthetic oil, there is not the viscosity break down issues. You still have contaminants that get in your oil.I don't know that I would go 7500 miles on a oil change (with synthetic) myself. Just my opinion.



True, but synthetics suspend particulate contaminants differently than organic oils. In organic oils, the contaminates (carbon from combustion, mostly) builds up and actually becomes an abrasive. Synthetics don't allow that to happen. If you use organic oils, then 5000mi would probably be the max you should go. Semi-synthetics, maybe 7500mi. Full synthetic oils, 10,000+. But then one should change the oil at least once a year, no matter the mileage (twice in extreme conditions/weather)

You might look on sites such as Redline or Amsoil for much more definitive information.

I know people who change every 15-20K miles, and have done so for years. Not that I would do it, but it can be done.


Is the bolded part above true ?



:popcorn:

.

[Carnut]

Differently is a pretty generalized statement. I have never read anything that states particle contaminents in synthetic oil vs organic make particle contaminents any less abrasive.

Contaminents are contaminents and it is the oil filter that removes most them (or an oil change). Engine oils break down with heat and contamination, whether they be synthetic or organic, except that synthetics resist this break down longer than organics extending the change intervals.

Another consideration too is that not all synthetic oils are created equally, some that are labeled as full synthetics actually are a blend of synthetic and fossil bases. I think Amsoil might be one of the few that is a true full synthetic. Ain't that a kick.

So, I guess am calling BS on that one (from a particle standpoint and assuming filtration is equal).

[The Bone]

The Nut is right. So my recommendation is to buy the best filter you can and then you can run you're car longer between oil changes. I usually change the oil in the Cirrus at 7 to 8 thousand miles. Currently I have 238,000 miles on it. I usually change it when it is down a quart so you can see that it doesn't burn much oil. I use nothing but Mobile 1 in all my cars except the gt500 cause it calls for Ford oil.
Why people make so much out of oil it amazes me. I usually run oil that meats or exceeds manufacture recommendations and go for it.. I have had good luck with Mobile 1 some have had good luck with Casteroil.
I was under the impression that full synthetic was not a blend unless it said so on the quart

[JTB]

The Nut is right. So my recommendation is to buy the best filter you can and then you can run you're car longer between oil changes. I usually change the oil in the Cirrus at 7 to 8 thousand miles. Currently I have 238,000 miles on it. I usually change it when it is down a quart so you can see that it doesn't burn much oil. I use nothing but Mobile 1 in all my cars except the gt500 cause it calls for Ford oil.
Why people make so much out of oil it amazes me. I usually run oil that meats or exceeds manufacture recommendations and go for it.. I have had good luck with Mobile 1 some have had good luck with Casteroil.
I was under the impression that full synthetic was not a blend unless it said so on the quart

That is the case here :canada: by federal regulations.

Mobil 1 is a great product, IMO as are their line of Synthetic Motorcycle Oils too.

[Carnut]

I was under the impression that full synthetic was not a blend unless it said so on the quart

I snipped the following from one website, there are numerous similar ones out there, you just need to look for them. So synthetic does not necessarily mean synthetic. Synthetic can be fossil based and called synthetic or be a blend. :redcard:This is an oil industry dirty little secret. You have to dig deep to find the truth. I think, even Mobil One used to be and may still really be a blend.:yikes:

As early as the 1990's, it was revealed to the public that many oil companies of the day were refining their petroleum oil to the point where it met these standards instead of starting with a base synthetic stock. While it was completely legal for these companies to call their oil synthetic, it was actually birthed from a completely different chemistry than traditional synthetic oils, which used polyalphaolefin as its base.
:wow2:
This type of marketing was later ruled as a deceptive form of advertising, and there were many lawsuits that sprang up as a result of this. When the dust finally settled, it was ruled that the word "synthetic" was considered nothing more than a marketing term. The end result of this was that any highly refined petroleum oil that met the necessary standards could be labeled as synthetic.

[Carnut]

That is the case here :canada: by federal regulations.

Mobil 1 is a great product, IMO as are their line of Synthetic Motorcycle Oils too.

I would double check that JTB. See my post above and scrutinize the manufacturers data sheets. I'm not familar with Canadian law but you might be surprised.

[68fastback]

Fossil-based synthetics are actually truly synthetics -- it's just referring to the source of the chemical chains, as I understand it. Some niche oil companies make a big deal about 'true' synthetic vs synthetics from fossil sources but my understanding is that is actually just clever marketing hype. Once the molecular structure is disassembled and restrutured (synthecised from whatever source) it matters not, I believe, for any given oil spec what the source of the original molecules was before synthesis -- tho it's admittedly used to great marketing advantage/gamesmanship. Ultimately it's the chemical makeup/structure aand impurities that matters and there are different synthetic base-groups that oil makers work with. Some oil companies claim some are better than others (more sheer tolerant, etc) but any correct-grade synthetic is head and shoulders above any conventional oil which has hugely-higher ash/abrasives/impurities content, imo. These 'defects' are way to small for the oil filter to filter, so it does matter. Way back when, Pennzoil became famous because the Pennsylvania crude it was refined from was uniquely low in ash/abrasives and therefore made a superior lubricating oil -- that most every racer used, however, synthetics are great leaps ahead of even the best-refined conventional base-stock fossil oils in this regard, as I understand it, and remains one of the primary benefits of synthetics (reagrdless of original molecular source) -- less wear, especially during the several seconds of pre-pressure cold-starts when 80-90% of engine wear occurs. This is why racers, fleet truckers, huge ship engines and other applications where long-life is critical, all use pre-pressurization -- it simply extends the life of the engine dramatically. Parnelli Jones was an avid proponent of using pre-pressurizers which he used on his truck fleet as far back as the 60s.

[Tommy Gun]

I am sending in an oil sample from the SHO which has had Motorcraft Syn-Blend 5W20 in it.

The car now has 9600 miles on it. Just trying to see how long we may actually go between changes.

Ford says 7500 miles. We have done it twice so far though.

I'll post results when I get it and you all can figure it out. :rofl3:

[Vette Killer]

The easiest way to understand this is that with synthetic oils (yes, they are all organic...no one "makes" oil) have the polymer chains uniform in size and alignment....a good analogy is to think of a bunch of pencils of various lengths and diameters and a bunch of pencils that are all the same shape and size...the refining process for synthetic oils aligns the pencils so they are all the same size and shape in the base stock...it is more of a "sorting process" than anything....

What this does is reduce the friction within the oil itself which provides more uniform load bearing capacity, a more consistent viscosity, reduced oil heat generation (internally within the oil), increased heat disapation, and longer spec oil performance life.

The only part of any oil that is truly "synthetic" is the additive package...people assume the word synthetic means manufactured, from an oil perspective synthetic means modified from it's natural state. Almost every oil today is synthetic whether it is marketed with that in the title or not; the only oils that aren't synthetic are very low grade oils and greases where the base spec already out performs the lube requirement so the minimal cost saving reduces the operating cost.

The bolded statement is actually true on a molecular level but it is a theoretical statement only as you would not be able to find what they are calling organic oil (i.e. non-synthetic) for sale that met the performance spec you need....

[Tommy Gun]

My brain is fried now. :look:



.

[Carnut]

Fossil-based synthetics are actually truly synthetics -- it's just referring to the source of the chemical chains, as I understand it. Some niche oil companies make a big deal about 'true' synthetic vs synthetics from fossil sources but my understanding is that is actually just clever marketing hype. Once the molecular structure is disassembled and restrutured (synthecised from whatever source) it matters not, I believe, for any given oil spec what the source of the original molecules was before synthesis -- tho it's admittedly used to great marketing advantage/gamesmanship. Ultimately it's the chemical makeup/structure aand impurities that matters and there are different synthetic base-groups that oil makers work with. Some oil companies claim some are better than others (more sheer tolerant, etc) but any correct-grade synthetic is head and shoulders above any conventional oil which has hugely-higher ash/abrasives/impurities content, imo. These 'defects' are way to small for the oil filter to filter, so it does matter. Way back when, Pennzoil became famous because the Pennsylvania crude it was refined from was uniquely low in ash/abrasives and therefore made a superior lubricating oil -- that most every racer used, however, synthetics are great leaps ahead of even the best-refined conventional base-stock fossil oils in this regard, as I understand it, and remains one of the primary benefits of synthetics (reagrdless of original molecular source) -- less wear, especially during the several seconds of pre-pressure cold-starts when 80-90% of engine wear occurs. This is why racers, fleet truckers, huge ship engines and other applications where long-life is critical, all use pre-pressurization -- it simply extends the life of the engine dramatically. Parnelli Jones was an avid proponent of using pre-pressurizers which he used on his truck fleet as far back as the 60s.

Exactly!

Now that we have that out of the way, I don't believe there is really much validity to the claim in the first post. The inference was that if you ran synthetic oil, you didn't have to worry about contaminents. It is really about the API grade and specification, not whether or not it is fossil based.

Even with the best grade oil, synthetic or not, you need a filter to remove some of those cataminents that are products of combustion, no filter will remove them all. (not even the old toilet paper filters they tried to sell the public in the eighties :rofl3:) And there is a difference in filters. Eventually you end up adding enough contaminents to any oil, that is too small to filter, and you need to change the oil to get rid of them.

As you stated, many racers used accumulators and they still do. They are a wonderful device for ensuring everything is lubricated before start up. I suspect they will do more for engine wear that anything else. I have read claims that 75 percent of engine wear is due to lack of lubrication at cold start up.

And yes synthetics are by far a more superior product to "regular" motor oils as far as its lubricating properties are concerned. I am more concerned about the EPA mandated removal of certain chemical compounds from "most" oil. Zinc and Phosphorus prevented galling of flat tappet lifters and camshafts, rocker arms and other parts of the engine. Modern engines have gone to roller cams and different rocker arms designs. I personally know, 3 people who lost camshafts soon after going to Mobil One synthetic. The oil industry worked hard to put these compounds back into a few "off road only" oils. Valvoline VR-1 racing oil is one, there are others. Warning here: The industry claims that zinc and phosphorus will contaminate catalytic converters, reducing their service life. So you might not want to use it in your late model cars.

Getting back to more on topic, oil change intervals (synthetic or not) should be predicated upon vehicle useage in addition to number of miles. If you are racing a car, working a motor really hard, and lots of cold starts, you need to increase your oil changes because you pick up more contaminents that can't be filtered out. It's really a guessing game and most owners would not know the difference because the wear shows up at extreme mileage, long after most people have sold there car or broke it for different reasons.

I won't call my brother cheap, but he will run a car into the extreme mileage limits. Many over 300,000 without an internal engine problem. He uses "regular" motor oil. I believe it is because he religiously changes his oil at 3,000 mile intervals. You can pull a valve cover on those old motors and they appear as clean as when they were new.

[Tommy Gun]

....I won't call my brother cheap, but he will run a car into the extreme mileage limits. Many over 300,000 without an internal engine problem. He uses "regular" motor oil. I believe it is because he religiously changes his oil at 3,000 mile intervals. You can pull a valve cover on those old motors and they appear as clean as when they were new.



So there are 2 squirrels driving on the roads? :faint:

.

[68fastback]

Exactly!

Now that we have that out of the way, I don't believe there is really much validity to the claim in the first post. The inference was that if you ran synthetic oil, you didn't have to worry about contaminents. It is really about the API grade and specification, not whether or not it is fossil based.

Even with the best grade oil, synthetic or not, you need a filter to remove some of those cataminents that are products of combustion, no filter will remove them all. (not even the old toilet paper filters they tried to sell the public in the eighties :rofl3:) And there is a difference in filters. Eventually you end up adding enough contaminents to any oil, that is too small to filter, and you need to change the oil to get rid of them.

As you stated, many racers used accumulators and they still do. They are a wonderful device for ensuring everything is lubricated before start up. I suspect they will do more for engine wear that anything else. I have read claims that 75 percent of engine wear is due to lack of lubrication at cold start up.

And yes synthetics are by far a more superior product to "regular" motor oils as far as its lubricating properties are concerned. I am more concerned about the EPA mandated removal of certain chemical compounds from "most" oil. Zinc and Phosphorus prevented galling of flat tappet lifters and camshafts, rocker arms and other parts of the engine. Modern engines have gone to roller cams and different rocker arms designs. I personally know, 3 people who lost camshafts soon after going to Mobil One synthetic. The oil industry worked hard to put these compounds back into a few "off road only" oils. Valvoline VR-1 racing oil is one, there are others. Warning here: The industry claims that zinc and phosphorus will contaminate catalytic converters, reducing their service life. So you might not want to use it in your late model cars.

Getting back to more on topic, oil change intervals (synthetic or not) should be predicated upon vehicle useage in addition to number of miles. If you are racing a car, working a motor really hard, and lots of cold starts, you need to increase your oil changes because you pick up more contaminents that can't be filtered out. It's really a guessing game and most owners would not know the difference because the wear shows up at extreme mileage, long after most people have sold there car or broke it for different reasons.

I won't call my brother cheap, but he will run a car into the extreme mileage limits. Many over 300,000 without an internal engine problem. He uses "regular" motor oil. I believe it is because he religiously changes his oil at 3,000 mile intervals. You can pull a valve cover on those old motors and they appear as clean as when they were new.

Yep, we're definately on the same page re contaminants, etc.

Re your bro ...when we got the '93 Taurus (5-years old) it would eat a 1/2 qt in about 800 miles. Now after religiously changing the oil ever 3000 miles (using mostly good 5w30 and occasionally MC 5w30 synth blend) , and with a couple hundred thou miles it goes 1800-2000 miles before getting a 1/2 qt down. Clearly changing the oil regularly/often has merit, imo. Possibly because full synth oil is so chemically homogenous it may be able to tolerate more fine combustive by-product contaminants (longer change interval) before it's wear characteristics become elevated to the equivalent of conventional oil but I totally agree with you that these contaminants are still there and are unavoidable.

On the 2009 Fusion Ford specifies semi-synthetic oil but recommends full synthetic *however* in the fine footnote they say that conventional oil that meets the stated oil spec will not void the warranty. Surprisingly the change interval is 7500 regardless. Pretty confusing. Given we only put about 8,500-9,000/year on the Taurus and would likely put the same on the Fusion, I'm figuring for the difference in cost synthetic is worth it. We already have about 3,300 miles on the oil (MC semi-synth) and there has been zero detectable consumption, so I'm figuring over the long haul changing twice a year (spring and fall) with synthetic is our best bet for long-life ...since we'll probably keep this car for at least a couple hundred thou.

My brother was a salesman who put 50-60K miles/year on his car -- the last three he had were all Taurus wagons (3.0L, just like ours) and he changed the oil (conventional) religiously three times ever 10K miles (every few weeks!) and he ran them all to 300-350K miles before unloading them on family or a friend who would drive them another 100K. This is what convinced me that frequent changes makes a difference, tho not a scientific study.

My 460 4x4 van, on the other hand, had it's oil changed evbery 3K miles religiously but that piston-slap had nothing to do with wear ...it was clearly a defect. It was hard for Ford to argue with me since I had records on the oil changes ...many of which the dealer did. Different subject, but when Ford finally agreed to spring for the replacement engine they would only agree to pay for a Ford-certified remanufactured with a 5 year warranty. If I had insisted on a new factory motor I would have had to pay for part of the cost and it would only carry a 1-year warranty -- go figure ...that just never made sense to me and I went with the freebie remanufactured which ran flawlessley for another 20+ years (and is now in storage at the son's house of the guy I originally bought it from in 1978) ...and I changed the oil every 3K miles on that too.

[Tommy Gun]

:reading:


.

[Carnut]

Yep, we're definately on the same page re contaminants, etc.

Re your bro ...when we got the '93 Taurus (5-years old) it would eat a 1/2 qt in about 800 miles. Now after religiously changing the oil ever 3000 miles (using mostly good 5w30 and occasionally MC 5w30 synth blend) , and with a couple hundred thou miles it goes 1800-2000 miles before getting a 1/2 qt down. Clearly changing the oil regularly/often has merit, imo. Possibly because full synth oil is so chemically homogenous it may be able to tolerate more fine combustive by-product contaminants (longer change interval) before it's wear characteristics become elevated to the equivalent of conventional oil but I totally agree with you that these contaminants are still there and are unavoidable.

On the 2009 Fusion Ford specifies semi-synthetic oil but recommends full synthetic *however* in the fine footnote they say that conventional oil that meets the stated oil spec will not void the warranty. Surprisingly the change interval is 7500 regardless. Pretty confusing. Given we only put about 8,500-9,000/year on the Taurus and would likely put the same on the Fusion, I'm figuring for the difference in cost synthetic is worth it. We already have about 3,300 miles on the oil (MC semi-synth) and there has been zero detectable consumption, so I'm figuring over the long haul changing twice a year (spring and fall) with synthetic is our best bet for long-life ...since we'll probably keep this car for at least a couple hundred thou.

My brother was a salesman who put 50-60K miles/year on his car -- the last three he had were all Taurus wagons (3.0L, just like ours) and he changed the oil (conventional) religiously three times ever 10K miles (every few weeks!) and he ran them all to 300-350K miles before unloading them on family or a friend who would drive them another 100K. This is what convinced me that frequent changes makes a difference, tho not a scientific study.

My 460 4x4 van, on the other hand, had it's oil changed evbery 3K miles religiously but that piston-slap had nothing to do with wear ...it was clearly a defect. It was hard for Ford to argue with me since I had records on the oil changes ...many of which the dealer did. Different subject, but when Ford finally agreed to spring for the replacement engine they would only agree to pay for a Ford-certified remanufactured with a 5 year warranty. If I had insisted on a new factory motor I would have had to pay for part of the cost and it would only carry a 1-year warranty -- go figure ...that just never made sense to me and I went with the freebie remanufactured which ran flawlessley for another 20+ years (and is now in storage at the son's house of the guy I originally bought it from in 1978) ...and I changed the oil every 3K miles on that too.

I believe that the time usage, interval and climate have a very profound effect on when oil is changed (besides just mileage and regular, blend or synthetic).

One extreme is a cold climate, car driven a few miles a day. The engine never warms fully and allows moisture to condense in the crankcase and rocker arm valleys. It doesn't get hot enough for heat to get rid of that moisture. In addition you are adding a little unburned fuel to it. The oil quickly loses it lubricating qualities because it is diluted with water and gasoline. The oil change interval should be increased to every few months during cold weather, regardless of the mileage.

The other extreme would be your saleman brother, runs the car to a fully warm condition for many miles at a time. The engine is hot enough to disperse moisture from the system through heat and crankcase evacuation. There is very little fuel enrichment to contaminate the oil. The oil change interval would certainly be based upon mileage, not time.

I've seen oil from the short drive scenario and often it is milky white (water in the oil). You add cold temperatures to it and it smells like gas and is milky white, not good for sure. Oil like this causes extreme wear to the engine. Using low temperature thermostats constributes to this problem because it keeps the engine from maintaining a fully hot condition long enough to allow moisture to be dispersed.

Regarding Fords oil change interval being the same regardless of type of oil, I think it is their attempt to get people to change their oil, sort of averaging the above extreme scenarios. The extended range for oil changes is likely due to closer tolerances in newer engines, better fuel management (fuel and combustion contamination), quicker warm-up and hotter engine temperatures (moisture removal) and lastly a marketing ploy to demonstrate economy of operation.

I have a number of cars that stay in my climate controlled garage. While mileage and time intervals play an indirect indicator of when I change the oil, some of them may go a couple years between changes. In these cases, they might get driven less than 1,000 miles in a year, they warm to fully hot when they are driven, they don't pick up moisture sitting there, etc. In this case, I will actually look at the oil and smell it. If its still the same honey gold as it came out of the bottle and doesn't smell like gasoline, it's good to go. On my blower car with dual quads, when its gets to smelling like gasoline (and it will), its time for an oil change. If it's turned black or milky, time for an oil change. In these cases, I don't find running synthetic oil to be of any benefit.

I do run the full synthetic in my Shelby though, because the manufacture specifies it. I only have 6,000 miles on it and have exceed the time interval specified, changing it at 2500 miles and two years (nearly). This car gets fully hot each time I drive it, which is about once a week.

Now my wife's car is a different thing, she thinks the only time you change the oil is when you trade it in.

[JTB]

I believe that the time usage, interval and climate have a very profound effect on when oil is changed (besides just mileage and regular, blend or synthetic).

One extreme is a cold climate, car driven a few miles a day. The engine never warms fully and allows moisture to condense in the crankcase and rocker arm valleys. It doesn't get hot enough for heat to get rid of that moisture. In addition you are adding a little unburned fuel to it. The oil quickly loses it lubricating qualities because it is diluted with water and gasoline. The oil change interval should be increased to every few months during cold weather, regardless of the mileage.

The other extreme would be your saleman brother, runs the car to a fully warm condition for many miles at a time. The engine is hot enough to disperse moisture from the system through heat and crankcase evacuation. There is very little fuel enrichment to contaminate the oil. The oil change interval would certainly be based upon mileage, not time.

I've seen oil from the short drive scenario and often it is milky white (water in the oil). You add cold temperatures to it and it smells like gas and is milky white, not good for sure. Oil like this causes extreme wear to the engine. Using low temperature thermostats constributes to this problem because it keeps the engine from maintaining a fully hot condition long enough to allow moisture to be dispersed.

Regarding Fords oil change interval being the same regardless of type of oil, I think it is their attempt to get people to change their oil, sort of averaging the above extreme scenarios. The extended range for oil changes is likely due to closer tolerances in newer engines, better fuel management (fuel and combustion contamination), quicker warm-up and hotter engine temperatures (moisture removal) and lastly a marketing ploy to demonstrate economy of operation.

I have a number of cars that stay in my climate controlled garage. While mileage and time intervals play an indirect indicator of when I change the oil, some of them may go a couple years between changes. In these cases, they might get driven less than 1,000 miles in a year, they warm to fully hot when they are driven, they don't pick up moisture sitting there, etc. In this case, I will actually look at the oil and smell it. If its still the same honey gold as it came out of the bottle and doesn't smell like gasoline, it's good to go. On my blower car with dual quads, when its gets to smelling like gasoline (and it will), its time for an oil change. If it's turned black or milky, time for an oil change. In these cases, I don't find running synthetic oil to be of any benefit.

I do run the full synthetic in my Shelby though, because the manufacture specifies it. I only have 6,000 miles on it and have exceed the time interval specified, changing it at 2500 miles and two years (nearly). This car gets fully hot each time I drive it, which is about once a week.

Now my wife's car is a different thing, she thinks the only time you change the oil is when you trade it in.

:spitcopy:

[Black Vert SS]

I'll throw another scenerio into the mix:

In my Diesel bucket trucks the boom or bucket runs off the main engine. So while the trucks are driven to the job site (sometimes only a couple of miles) the truck can run all day at a high idle (1100rpm) while the bucket is used. So I can neither go by mileage or standard time (days on the road). My trucks don't come with an hour meter and cummins has no recommendations that I could find for their engines used the way I use them. So I try to change the oil every 2-3 months. Maybe I should do it more but that seems to have worked so far. So while my oldest bucket truck has only 90,000 miles on it, in reality it may have over 150,000 miles based on the usage I put on them. The problem is there is no way to really tell. The other reason for more frequent changes is the anount of dust we generate while chipping branches. We have to change air filters every month or you really notice a drop in power in the engines.

[Carnut]

I'll throw another scenerio into the mix:

In my Diesel bucket trucks the boom or bucket runs off the main engine. So while the trucks are driven to the job site (sometimes only a couple of miles) the truck can run all day at a high idle (1100rpm) while the bucket is used. So I can neither go by mileage or standard time (days on the road). My trucks don't come with an hour meter and cummins has no recommendations that I could find for their engines used the way I use them. So I try to change the oil every 2-3 months. Maybe I should do it more but that seems to have worked so far. So while my oldest bucket truck has only 90,000 miles on it, in reality it may have over 150,000 miles based on the usage I put on them. The problem is there is no way to really tell. The other reason for more frequent changes is the anount of dust we generate while chipping branches. We have to change air filters every month or you really notice a drop in power in the engines.

Makes sense for sure.

Does the oil smell like diesel fuel when you change it? Is it completely black? Or milky? If not, my guess is your interval is ballpark okay. JMO.

[Black Vert SS]

Makes sense for sure.

Does the oil smell like diesel fuel when you change it? Is it completely black? Or milky? If not, my guess is your interval is ballpark okay. JMO.

The oil seems to turn black very quickly. Never milky or smelly. When my injectors went bad there was oil in the fuel filter but never the other way around.

[Carnut]

The oil seems to turn black very quickly. Never milky or smelly. When my injectors went bad there was oil in the fuel filter but never the other way around.

Turning dark is fine, I guess what I meant is it so black it looks like black ink without any opacity whatsoever.

[68fastback]

I believe that the time usage, interval and climate have a very profound effect on when oil is changed (besides just mileage and regular, blend or synthetic).

One extreme is a cold climate, car driven a few miles a day. The engine never warms fully and allows moisture to condense in the crankcase and rocker arm valleys. It doesn't get hot enough for heat to get rid of that moisture. In addition you are adding a little unburned fuel to it. The oil quickly loses it lubricating qualities because it is diluted with water and gasoline. The oil change interval should be increased to every few months during cold weather, regardless of the mileage.

The other extreme would be your saleman brother, runs the car to a fully warm condition for many miles at a time. The engine is hot enough to disperse moisture from the system through heat and crankcase evacuation. There is very little fuel enrichment to contaminate the oil. The oil change interval would certainly be based upon mileage, not time.

I've seen oil from the short drive scenario and often it is milky white (water in the oil). You add cold temperatures to it and it smells like gas and is milky white, not good for sure. Oil like this causes extreme wear to the engine. Using low temperature thermostats constributes to this problem because it keeps the engine from maintaining a fully hot condition long enough to allow moisture to be dispersed.

Regarding Fords oil change interval being the same regardless of type of oil, I think it is their attempt to get people to change their oil, sort of averaging the above extreme scenarios. The extended range for oil changes is likely due to closer tolerances in newer engines, better fuel management (fuel and combustion contamination), quicker warm-up and hotter engine temperatures (moisture removal) and lastly a marketing ploy to demonstrate economy of operation.

I have a number of cars that stay in my climate controlled garage. While mileage and time intervals play an indirect indicator of when I change the oil, some of them may go a couple years between changes. In these cases, they might get driven less than 1,000 miles in a year, they warm to fully hot when they are driven, they don't pick up moisture sitting there, etc. In this case, I will actually look at the oil and smell it. If its still the same honey gold as it came out of the bottle and doesn't smell like gasoline, it's good to go. On my blower car with dual quads, when its gets to smelling like gasoline (and it will), its time for an oil change. If it's turned black or milky, time for an oil change. In these cases, I don't find running synthetic oil to be of any benefit.

I do run the full synthetic in my Shelby though, because the manufacture specifies it. I only have 6,000 miles on it and have exceed the time interval specified, changing it at 2500 miles and two years (nearly). This car gets fully hot each time I drive it, which is about once a week.

Now my wife's car is a different thing, she thinks the only time you change the oil is when you trade it in.

All good advice, Bruce...

I've seen some farm jeeps that are just used as a runnabout (to and from the field equipment and occasionally jocckeying 'empties') but that rearely if ever see full warm up and the sludge build-up can be unfathomable ...think valve covers so full that the only voids are where the rocker arms move :yikes: ...that fellow told me he changes the oil "every few years" :rofl3:

Also, I shold point out that full warm-up (for condensation considerations) has not occurred when the coolant temp shows that it's up to temp -- it takes a good 20 minutes of use to drive engine heat into all the nooks and crannies of the engine and drive condensate moisture out which, along with combustion byproducts (hydrocarbons) can make some serious hydrocloric acid ...until burned off. This is why shutdown before a full warm-up matters in general, and especially before storage.

...so for those who store their ride over the winter and tend to change the oil when it comes out of hibernation, consider doing it before you put her to sleep to remove any combustion byproduct derived acid contamination ...then take it up to full temp after the oil change. Probably not a biggie, but anything that's no more work/expense and makes a real difference is a good thing, imo.

[Tommy Gun]

BVSS is in a tech thread. :faint:


.

[Black Vert SS]

BVSS is in a tech thread. :faint:


.

And not going to the PW dump either :jiggy: