Does operating temperature heat burn off...
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I believe getting to operating temperature (above 212F) typically allows the water that might be in the crank to effectively boil. Once it's vaporized, it can makes its way through the PCV and burned up.
I think it all depends on the boiling point of the stuff, but like, obviously gas should vaporize and burn out. I think the water in the coolant will boil, but other parts within the coolant may not, which is why it can be measured in a UOA.
If there's coolant in the oil you have problems.
Originally Posted By: paulri
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Water won't burn, but will mostly evaporate, without necessarily boiling. Gasoline in the oil will partially evaporate at operating temperature---taking some oil with it through the PCV system, assuming that system is intact.
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Water won't burn, but will mostly evaporate, without necessarily boiling. Gasoline in the oil will partially evaporate at operating temperature---taking some oil with it through the PCV system, assuming that system is intact.
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I can tell you this much: I've had coolant leaks into the oil that most certainly showed up on UOA; so I would say NO, an engine at normal operating temperature will NOT "burn off" coolant.
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I've read that water will burn off/evaporate after fifteen minutes of driving, which is why they say it's important to avoid short trips and get your car out there once in a while. Gas evaporates pretty easily but the contents of combustion that enter the oil will eventually over saturate it. And coolant shouldn't be getting into your oil, but I imagine traces of it probably do on occasion.
This is why we change our oil, because these things get into it, make it "dirty" and eventually saturate it. I've changed oil that is so black and almost kind of gritty to the touch, that it makes you wonder...why didn't they just change it sooner? And I bet a UOA would show that oil to be just fine, but is it really?
This is why we change our oil, because these things get into it, make it "dirty" and eventually saturate it. I've changed oil that is so black and almost kind of gritty to the touch, that it makes you wonder...why didn't they just change it sooner? And I bet a UOA would show that oil to be just fine, but is it really?
Originally Posted By: paulri
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Originally Posted By: paulri
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Any water content will be fully evaporated out of the oil whenever the engine is run for some reasonable time on a start.
Fuel won't be nor will coolant.
Fuel is fully solvent in the oil and cannot be evaporated out.
Just as an example, I posted a UOA from my old BMW in August 2012 which showed 2.9% fuel content. The car was driven 4K in two mid summer months and spent many of these miles on the interstate. It was short tripped rarely if at all and yet the fuel was still there.
Coolant is a mix of chemicals and is deadly to the bearings aside from turning the oil into a chocolate milkshake.
It won't be evaporated out and shouldn't find its way in unless you have serious problems.
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Originally Posted By: paulri
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Any water content will be fully evaporated out of the oil whenever the engine is run for some reasonable time on a start.
Fuel won't be nor will coolant.
Fuel is fully solvent in the oil and cannot be evaporated out.
Just as an example, I posted a UOA from my old BMW in August 2012 which showed 2.9% fuel content. The car was driven 4K in two mid summer months and spent many of these miles on the interstate. It was short tripped rarely if at all and yet the fuel was still there.
Coolant is a mix of chemicals and is deadly to the bearings aside from turning the oil into a chocolate milkshake.
It won't be evaporated out and shouldn't find its way in unless you have serious problems.
Originally Posted By: fdcg27
Originally Posted By: paulri
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Originally Posted By: paulri
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Any water content will be fully evaporated out of the oil whenever the engine is run for some reasonable time on a start.
Fuel won't be nor will coolant.
Fuel is fully solvent in the oil and cannot be evaporated out.
Just as an example, I posted a UOA from my old BMW in August 2012 which showed 2.9% fuel content. The car was driven 4K in two mid summer months and spent many of these miles on the interstate. It was short tripped rarely if at all and yet the fuel was still there.
Coolant is a mix of chemicals and is deadly to the bearings aside from turning the oil into a chocolate milkshake.
It won't be evaporated out and shouldn't find its way in unless you have serious problems.
Are your sure about this? Even though gasoline is miscible, it still becomes the lightest compound in motor oil and will be the first component to volatize when temperatures get high. In fact, even absent gas in the oil, the light compounds of motor oil are what seems to create intake valve deposits in DI engines when they become volatile and are drawn thought the PCV system. And isn't evaporation of motor oil's components when heated what Noack measures?
That your BMW had fuel in the oil even when mostly highway-driven is probably because new fuel was constantly added to the oil, replacing what was evaporating. Or perhaps you had an injector leaking after shut-down.
Originally Posted By: paulri
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Originally Posted By: paulri
Does running the engine at "operating temperature" burn off just water, or does it also burn off gas and coolant that have seeped into the oil?
Any water content will be fully evaporated out of the oil whenever the engine is run for some reasonable time on a start.
Fuel won't be nor will coolant.
Fuel is fully solvent in the oil and cannot be evaporated out.
Just as an example, I posted a UOA from my old BMW in August 2012 which showed 2.9% fuel content. The car was driven 4K in two mid summer months and spent many of these miles on the interstate. It was short tripped rarely if at all and yet the fuel was still there.
Coolant is a mix of chemicals and is deadly to the bearings aside from turning the oil into a chocolate milkshake.
It won't be evaporated out and shouldn't find its way in unless you have serious problems.
Are your sure about this? Even though gasoline is miscible, it still becomes the lightest compound in motor oil and will be the first component to volatize when temperatures get high. In fact, even absent gas in the oil, the light compounds of motor oil are what seems to create intake valve deposits in DI engines when they become volatile and are drawn thought the PCV system. And isn't evaporation of motor oil's components when heated what Noack measures?
That your BMW had fuel in the oil even when mostly highway-driven is probably because new fuel was constantly added to the oil, replacing what was evaporating. Or perhaps you had an injector leaking after shut-down.
So why does your Honda show >5% fuel content in its oil?
In the case of the BMW, the M42 has a pretty rich fuel map and every UOA I've seen for this engine shows evidence of fuel content in the engine oil, either directly or inferred through a loss in viscosity.
Fuel becomes a part of the oil formulation through solvency and would represent a lighter fraction and would therefore be first to evaporate. However, water is not solvent in oil so evaporates readily, while fuel is solvent and doesn't.
You should consider the test protocol by which oil volatility is measured. It involves bulk oil temperatures that your car and mine will never see over a fairly long time interval. It's a standardized lab test, not a realistic depiction of oil temperatures in any street engine.
Finally, understand the point that I made.
Water evaporates readily from the sump because it isn't solvent in oil. Fuel doesn't because it is.
In the case of the BMW, the M42 has a pretty rich fuel map and every UOA I've seen for this engine shows evidence of fuel content in the engine oil, either directly or inferred through a loss in viscosity.
Fuel becomes a part of the oil formulation through solvency and would represent a lighter fraction and would therefore be first to evaporate. However, water is not solvent in oil so evaporates readily, while fuel is solvent and doesn't.
You should consider the test protocol by which oil volatility is measured. It involves bulk oil temperatures that your car and mine will never see over a fairly long time interval. It's a standardized lab test, not a realistic depiction of oil temperatures in any street engine.
Finally, understand the point that I made.
Water evaporates readily from the sump because it isn't solvent in oil. Fuel doesn't because it is.
Originally Posted By: fdcg27
So why does your Honda show >5% fuel content in its oil?
In the case of the BMW, the M42 has a pretty rich fuel map and every UOA I've seen for this engine shows evidence of fuel content in the engine oil, either directly or inferred through a loss in viscosity.
Fuel becomes a part of the oil formulation through solvency and would represent a lighter fraction and would therefore be first to evaporate. However, water is not solvent in oil so evaporates readily, while fuel is solvent and doesn't.
You should consider the test protocol by which oil volatility is measured. It involves bulk oil temperatures that your car and mine will never see over a fairly long time interval. It's a standardized lab test, not a realistic depiction of oil temperatures in any street engine.
Finally, understand the point that I made.
Water evaporates readily from the sump because it isn't solvent in oil. Fuel doesn't because it is.
I'll try hard to keep up.
John Deere says this about how to prevent fuel dilution:
1) "Stay away from operating vehicle in short trips with light engine loads. The reason for this is that the engine oil temperature does not get hot enough to boil off fuel and moisture in the crankcase. Running the engine at operating temperature and under load for long enough periods will allow the fuel to evaporate."
John Deere's other suggestion if to use high quality, fresh fuel.
Maybe John Deere has it all wrong, but they seem like a credible source to me.
So why does your Honda show >5% fuel content in its oil?
In the case of the BMW, the M42 has a pretty rich fuel map and every UOA I've seen for this engine shows evidence of fuel content in the engine oil, either directly or inferred through a loss in viscosity.
Fuel becomes a part of the oil formulation through solvency and would represent a lighter fraction and would therefore be first to evaporate. However, water is not solvent in oil so evaporates readily, while fuel is solvent and doesn't.
You should consider the test protocol by which oil volatility is measured. It involves bulk oil temperatures that your car and mine will never see over a fairly long time interval. It's a standardized lab test, not a realistic depiction of oil temperatures in any street engine.
Finally, understand the point that I made.
Water evaporates readily from the sump because it isn't solvent in oil. Fuel doesn't because it is.
I'll try hard to keep up.
John Deere says this about how to prevent fuel dilution:
1) "Stay away from operating vehicle in short trips with light engine loads. The reason for this is that the engine oil temperature does not get hot enough to boil off fuel and moisture in the crankcase. Running the engine at operating temperature and under load for long enough periods will allow the fuel to evaporate."
John Deere's other suggestion if to use high quality, fresh fuel.
Maybe John Deere has it all wrong, but they seem like a credible source to me.
Okay, so if the engine is typically operated at moderately high loads for extended periods of time and fuel is still found in the oil, then what?
That was my experience and you've apparently shared it.
Deere & Co. may have it wrong, it appears.
That was my experience and you've apparently shared it.
Deere & Co. may have it wrong, it appears.
Originally Posted By: fdcg27
Okay, so if the engine is typically operated at moderately high loads for extended periods of time and fuel is still found in the oil, then what?
That was my experience and you've apparently shared it.
Deere & Co. may have it wrong, it appears.
Reasonable question. In my case it could be that, for whatever reason, a cylinder isn't sealing properly allowing blowby gases to enter the crankcase continuously offsetting the evaporation that occurs at temperature. Or in the case of your BMW, the rich mixture may have done the same thing.
Fwiw, the folks at Blackstone believe extended operation at highway temperatures evaporates fuel dilution. And our good friend Shannow has posted graphs in another thread that suggest we both may be right: different gasoline elements evaporate at different temperatures; some will evaporate at relatively low temperatures but some resist until temps unlikely to be met in normal operation.
It's a slippery issue...
Okay, so if the engine is typically operated at moderately high loads for extended periods of time and fuel is still found in the oil, then what?
That was my experience and you've apparently shared it.
Deere & Co. may have it wrong, it appears.
Reasonable question. In my case it could be that, for whatever reason, a cylinder isn't sealing properly allowing blowby gases to enter the crankcase continuously offsetting the evaporation that occurs at temperature. Or in the case of your BMW, the rich mixture may have done the same thing.
Fwiw, the folks at Blackstone believe extended operation at highway temperatures evaporates fuel dilution. And our good friend Shannow has posted graphs in another thread that suggest we both may be right: different gasoline elements evaporate at different temperatures; some will evaporate at relatively low temperatures but some resist until temps unlikely to be met in normal operation.
It's a slippery issue...
If you suspect a bad cylinder, pull all four plugs and have a look. The cylinder with a bad ring seal will be obvious and you can get Honda to warranty the repairs. Of course, if you had one bad pot you'd also have oil consumption and you don't mention that you do.
I'm not sure why DI engines often exhibit high fuel content in their engine oil.
I only know that they do.
Whether that'll impact engine life is another matter, since it appears that HTHSv is less diminished than is KV. Also, the effect of VIIs may limit the actual loss in KV.
In any event, once we see more 200K+ DI engines we'll know whether fuel dilution of the engine oil in street engines run under street conditions is of real concern or not.
This may all be much ado about nothing.
I'm not sure why DI engines often exhibit high fuel content in their engine oil.
I only know that they do.
Whether that'll impact engine life is another matter, since it appears that HTHSv is less diminished than is KV. Also, the effect of VIIs may limit the actual loss in KV.
In any event, once we see more 200K+ DI engines we'll know whether fuel dilution of the engine oil in street engines run under street conditions is of real concern or not.
This may all be much ado about nothing.
Beating a dead horse I know, but the State of Michigan has a web page outlining the tests it uses to assure gasoline sold has the proper volatility for the season. Acknowledging gasoline has a variety of components that volatize at different temperatures, it produces a table showing required evaporation %s at different temperatures.
Winter fuels are made to evaporate at lower temperatures to aid in cold weather starting, but a blended average from Michigan's test tables is roughly:
10% evaporation: c 140F
50% evaporation: c 150-250F
90% evaporation: c 370F
100% evaporation: c 440F
In typical operating conditions it seems most fully warmed engine oils top out at 190-200F, so it looks like around one-half of fuel diluting engine oil would evaporate in a normal highway drive. So yes, a good portion of the fuel will evaporate but a hefty residual will remain.
Winter fuels are made to evaporate at lower temperatures to aid in cold weather starting, but a blended average from Michigan's test tables is roughly:
10% evaporation: c 140F
50% evaporation: c 150-250F
90% evaporation: c 370F
100% evaporation: c 440F
In typical operating conditions it seems most fully warmed engine oils top out at 190-200F, so it looks like around one-half of fuel diluting engine oil would evaporate in a normal highway drive. So yes, a good portion of the fuel will evaporate but a hefty residual will remain.
Originally Posted By: Danh
1) "Stay away from operating vehicle in short trips with light engine loads. The reason for this is that the engine oil temperature does not get hot enough to boil off fuel and moisture in the crankcase. Running the engine at operating temperature and under load for long enough periods will allow the fuel to evaporate."
John Deere's other suggestion if to use high quality, fresh fuel.
Maybe John Deere has it all wrong, but they seem like a credible source to me.
Again, here's a diesel distillation curve
I think that their statement might be overly simplistic, and partially incorrect.
We had a JCB at work that was left idling for a shift not long after a rebuild, and the cylinders were scored as a result of cold operation, diesel washing the walls, and building sump level....worked, they don't dilute as much.
They might MEAN that low load operation leads to fuel dilution, in spite of what they are saying in overly simplistic terms.
I know that my Nissan can't be idled to warm-up after a coolant change, it needs 1,500 RPM, and there's a button on the dash for that.
1) "Stay away from operating vehicle in short trips with light engine loads. The reason for this is that the engine oil temperature does not get hot enough to boil off fuel and moisture in the crankcase. Running the engine at operating temperature and under load for long enough periods will allow the fuel to evaporate."
John Deere's other suggestion if to use high quality, fresh fuel.
Maybe John Deere has it all wrong, but they seem like a credible source to me.
Again, here's a diesel distillation curve
I think that their statement might be overly simplistic, and partially incorrect.
We had a JCB at work that was left idling for a shift not long after a rebuild, and the cylinders were scored as a result of cold operation, diesel washing the walls, and building sump level....worked, they don't dilute as much.
They might MEAN that low load operation leads to fuel dilution, in spite of what they are saying in overly simplistic terms.
I know that my Nissan can't be idled to warm-up after a coolant change, it needs 1,500 RPM, and there's a button on the dash for that.
You can idle a diesel all day and it won't warm up, they need to be under load to get to operating temp. A DPF reburn will put a lot of fuel in the sump.
Just getting your oil up to operating temperature, in itself does little to remove fuel. You need the constant flow of hot blow-by gas and purge air through the oil to 'pull' the light hydrocarbons into the vapour phase. The higher the blow-by rate, the higher the blow-by temperature and the longer you expose the oil to said blow-by, the better will be the degree of fuel stripping.
Having said that, it's almost impossible to totally eradicate fuel dilution once you have it. It's a quirk of the vapour pressure laws that the oil will start giving up some of its own light componentry before it gives up it's last drop of (admittedly much lighter) fuel.
It's also worth noting that over time, the 'fuel' you collect in your gasoline engine's sump isn't gasoline but something that's more akin to light kerosene. Again, it's just a reflection of the way the physics work.
Having said that, it's almost impossible to totally eradicate fuel dilution once you have it. It's a quirk of the vapour pressure laws that the oil will start giving up some of its own light componentry before it gives up it's last drop of (admittedly much lighter) fuel.
It's also worth noting that over time, the 'fuel' you collect in your gasoline engine's sump isn't gasoline but something that's more akin to light kerosene. Again, it's just a reflection of the way the physics work.
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