Anecdotally, I can agree with this. Plugging in an aftermarket oil pan heater on the Cruze's engine makes the engine warm up faster on really cold days. The ScanGauge II also reads 2-3 mpg higher on my morning commute on the mornings that I remember to plug it in.
Economy benefits of increasing (starting) oil temp
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That's quite a long warmup on that Jeep diesel. Ever since Shannow raised the warmup time question last year I've been watching mine closely. I get movement in the coolant temp gauge within the first 1/2 mile or so (2-3 minutes after shifting into gear as soon as normal idle speed is reached). And within 2 miles (4-5 minutes) the coolant is at normal operating temp. I don't run the heater until coolant reaches op temp as that just delays engine warmup. Engine rpm plays a big role in warmup once the car is moving...2000 rpm give or take 10% works good for me. Since our cars are quite capable of 200K-300K miles or more with "thoughtful" care and maintenance (often outlasting the rest of the car) a sophisticated pre-heater comes into play if your goal is to get to 300K-500K miles, though the rest of the car might bleed you dry in repairs. Now if I lived in arctic like conditions for months at a time, a pre-heater would make sense to me.
Pre-heating the oil in the sump is fine but it won't do anything to heat up the engine block and the coolant system. Even if the oil was circulated it would take quite a while. I would think that within 1-3 minutes of starting your car, the oil temp is already up to 45-75 deg F. even if it started out from 0-20 deg F. The thicker viscosity at start up temps probably protects your engine up into the 80-120 deg F temp range. As that viscosity thins out in the 120-160 deg F range, that's where you want to spend the least amount of time, until the chemical additive package is working properly. So I'm not so sure that pre-heating your sump engine oil above 40-60 deg F does all that much for you. Driving your vehicle at a sufficient rpm (2000) and load will get you through the corrosion temp range quick enough.
Pre-heating the oil in the sump is fine but it won't do anything to heat up the engine block and the coolant system. Even if the oil was circulated it would take quite a while. I would think that within 1-3 minutes of starting your car, the oil temp is already up to 45-75 deg F. even if it started out from 0-20 deg F. The thicker viscosity at start up temps probably protects your engine up into the 80-120 deg F temp range. As that viscosity thins out in the 120-160 deg F range, that's where you want to spend the least amount of time, until the chemical additive package is working properly. So I'm not so sure that pre-heating your sump engine oil above 40-60 deg F does all that much for you. Driving your vehicle at a sufficient rpm (2000) and load will get you through the corrosion temp range quick enough.
JHZR2
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FWIW, and for a car with known high oil temperatures (BMW 135i twin turbo), this is what I observed at one point:
Code:
Miles on trip Water T Oil T
146.5 71
146.6 100
147 124
147.5 157
147.7 165 first budge
148 172
148.5 182
149 195
149.2 200
149.5 206 first tick
150 216
150.2 216 2nd tick
150.5 220
150.5 220 3rd tick
151.6 220 4th tick
152.4 224
152.9 224 5th tick
153.6 220 6th tick
154.8 216 7th tick (full temp)
IIRC 7th tick is 240F, and the oil temperature gauge reads between 160-250 typically (the two major tick marks, the third being 340F). Of course these data are very specific to that vehicle, as well as the fact that I took them on a reasonably warm day. But its just trying to show the correlation and cross-over time to get the oil to temperature, in what is probably the best-case example by far (due to high oil temps in a relatively high performance vehicle).
Code:
Miles on trip Water T Oil T
146.5 71
146.6 100
147 124
147.5 157
147.7 165 first budge
148 172
148.5 182
149 195
149.2 200
149.5 206 first tick
150 216
150.2 216 2nd tick
150.5 220
150.5 220 3rd tick
151.6 220 4th tick
152.4 224
152.9 224 5th tick
153.6 220 6th tick
154.8 216 7th tick (full temp)
IIRC 7th tick is 240F, and the oil temperature gauge reads between 160-250 typically (the two major tick marks, the third being 340F). Of course these data are very specific to that vehicle, as well as the fact that I took them on a reasonably warm day. But its just trying to show the correlation and cross-over time to get the oil to temperature, in what is probably the best-case example by far (due to high oil temps in a relatively high performance vehicle).
Originally Posted By: JHZR2
FWIW, and for a car with known high oil temperatures (BMW 135i twin turbo), this is what I observed at one point:
Code:
Miles on trip Water T Oil T
146.5 71
146.6 100
147 124
147.5 157
147.7 165 first budge
148 172
148.5 182
149 195
149.2 200
149.5 206 first tick
150 216
150.2 216 2nd tick
150.5 220
150.5 220 3rd tick
151.6 220 4th tick
152.4 224
152.9 224 5th tick
153.6 220 6th tick
154.8 216 7th tick (full temp)
IIRC 7th tick is 240F, and the oil temperature gauge reads between 160-250 typically (the two major tick marks, the third being 340F). Of course these data are very specific to that vehicle, as well as the fact that I took them on a reasonably warm day. But its just trying to show the correlation and cross-over time to get the oil to temperature, in what is probably the best-case example by far (due to high oil temps in a relatively high performance vehicle).
JHZR2, thanks for posting that. Since I don't have an oil temp gauge this is very useful to me as my '99 LS1 Camaro is at normal coolant temp within 2-3 miles similar to your BMW. Since you don't state which of those 7 tick marks are the major ones (ie 160/250) can you re-post with that information. I've often wondered just when my oil temp gets to the normal 195-210F range. And having a dummy temp gauge makes it even worse.
FWIW, and for a car with known high oil temperatures (BMW 135i twin turbo), this is what I observed at one point:
Code:
Miles on trip Water T Oil T
146.5 71
146.6 100
147 124
147.5 157
147.7 165 first budge
148 172
148.5 182
149 195
149.2 200
149.5 206 first tick
150 216
150.2 216 2nd tick
150.5 220
150.5 220 3rd tick
151.6 220 4th tick
152.4 224
152.9 224 5th tick
153.6 220 6th tick
154.8 216 7th tick (full temp)
IIRC 7th tick is 240F, and the oil temperature gauge reads between 160-250 typically (the two major tick marks, the third being 340F). Of course these data are very specific to that vehicle, as well as the fact that I took them on a reasonably warm day. But its just trying to show the correlation and cross-over time to get the oil to temperature, in what is probably the best-case example by far (due to high oil temps in a relatively high performance vehicle).
JHZR2, thanks for posting that. Since I don't have an oil temp gauge this is very useful to me as my '99 LS1 Camaro is at normal coolant temp within 2-3 miles similar to your BMW. Since you don't state which of those 7 tick marks are the major ones (ie 160/250) can you re-post with that information. I've often wondered just when my oil temp gets to the normal 195-210F range. And having a dummy temp gauge makes it even worse.
Seems like something is missing from this equation maybe effects of back pressure on the exhaust system and pumping losses to extract heat from the exhaust to the oil.
That last graphic seems like cause for concern, though I'm not sure how much I believe it.
It seems to be saying that there is (net, or just some?) water condensation at "normal" operating temperatures, below about 100C, and only shows (net, or just some?) water evaporation above about 105C.
Intuitively that's fairly implausible.
Also seems to be saying that wear declines (close to zero on this graphic) between about 105 and 125C then ticks up a bit around 140C, though there is an overlap of the two flat lines which is probably them interpolating between points that aren't there (?)
Its not clear (to me) whether this wear/temperature relationship is supposed to be due to the water or other effects, say anti-wear component activation.
This presentation is a bit of a pitch (they seem to be selling a system) and this particular slide looks more like a concept sketch than actual experimental data (The source citation looks like a personal communication rather than a publication, though I don't read German)
That said, this suggests that water is harder to get rid of than perhaps most people would have expected.
I recently posted a link to a discussion on a light plane site, where it was stated that there was quite a lot of water in a fully warmed-up crankcase in steady state, normal-operating-temperature equilibrium.
https://www.pilotsofamerica.com/community/threads/makeshift-engine-heater.54384/page-3
https://bobistheoilguy.com/forums/ubbthreads.php/topics/4285178/Re:_Little_Used_Vehicles#Post4285178
The suggestion was to remove the dipstick and/or oil filler cap after switching off, to vent the wet gases.
Nobody liked the idea, but it seems to be making some sense.
It seems to be saying that there is (net, or just some?) water condensation at "normal" operating temperatures, below about 100C, and only shows (net, or just some?) water evaporation above about 105C.
Intuitively that's fairly implausible.
Also seems to be saying that wear declines (close to zero on this graphic) between about 105 and 125C then ticks up a bit around 140C, though there is an overlap of the two flat lines which is probably them interpolating between points that aren't there (?)
Its not clear (to me) whether this wear/temperature relationship is supposed to be due to the water or other effects, say anti-wear component activation.
This presentation is a bit of a pitch (they seem to be selling a system) and this particular slide looks more like a concept sketch than actual experimental data (The source citation looks like a personal communication rather than a publication, though I don't read German)
That said, this suggests that water is harder to get rid of than perhaps most people would have expected.
I recently posted a link to a discussion on a light plane site, where it was stated that there was quite a lot of water in a fully warmed-up crankcase in steady state, normal-operating-temperature equilibrium.
https://www.pilotsofamerica.com/community/threads/makeshift-engine-heater.54384/page-3
https://bobistheoilguy.com/forums/ubbthreads.php/topics/4285178/Re:_Little_Used_Vehicles#Post4285178
The suggestion was to remove the dipstick and/or oil filler cap after switching off, to vent the wet gases.
Nobody liked the idea, but it seems to be making some sense.
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Another suggestion was to use an aquarium pump to blow (optionally but preferably dried) air through the sump.
I suppose you could enhance this further by using an inert gas,though that proposal might trigger a re-run of the "I'll stick to 78% blend" nitrogen-in-tyres yadda, plus it might delay starting.
I suppose you could enhance this further by using an inert gas,though that proposal might trigger a re-run of the "I'll stick to 78% blend" nitrogen-in-tyres yadda, plus it might delay starting.
I take that bit about the citation being a personal communication back. Looks like a publication, though in German.
Also the "intuitively unlikely" comment refers to the low oil temperatures , not the water accumulation (which I suppose would be inevitable).
Having thought about it a bit more I realise I'm not sure my oil gets over 100C, since I've never attempted to measure oil temperature.
I'm still a bit unconvinced by the "risk of sudden engine damage" below 0C comment. I suppose this would be due to internal icing by free water, which would seem to be a hazard, but I've never heard of it happening.
Also the "intuitively unlikely" comment refers to the low oil temperatures , not the water accumulation (which I suppose would be inevitable).
Having thought about it a bit more I realise I'm not sure my oil gets over 100C, since I've never attempted to measure oil temperature.
I'm still a bit unconvinced by the "risk of sudden engine damage" below 0C comment. I suppose this would be due to internal icing by free water, which would seem to be a hazard, but I've never heard of it happening.
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You have an old mitsubishi, right?
I'm 100% sure the oil gets over 100°C in normal use in all the small petrol engines during summer.
I'm 100% sure the oil gets over 100°C in normal use in all the small petrol engines during summer.
I suppose the saving grace is that the blowby gases are a lot hotter than the dew point at origin, and won't necessarily be cooled to the oil temperature before they are purged by the crankcase ventilation system.
If they do go below the dew point, the condensed water will still be dispersed as fine mist in the crankcase gases, and some (perhaps most?) of them will be purged before they get into the oil.
(This won't apply when you switch off, hence the argument for purging those gases before they have a chance to settle out)
This probably means there is no net accumulation of water at just below 100C, though the break-even temperature might be difficult to predict and will partly depend on the efficiency of the crankcase ventilation system.
So the presentation IS probably exaggerating the problem. Phew!
If they do go below the dew point, the condensed water will still be dispersed as fine mist in the crankcase gases, and some (perhaps most?) of them will be purged before they get into the oil.
(This won't apply when you switch off, hence the argument for purging those gases before they have a chance to settle out)
This probably means there is no net accumulation of water at just below 100C, though the break-even temperature might be difficult to predict and will partly depend on the efficiency of the crankcase ventilation system.
So the presentation IS probably exaggerating the problem. Phew!
Originally Posted By: Jetronic
You have an old mitsubishi, right?
I'm 100% sure the oil gets over 100°C in normal use in all the small petrol engines during summer.
Thanks, reassuring. There does seem to be some disagreement on that (the presentation and other posters) but perhaps its less important than the presentation implies anyway (see above).
Might try and measure it. I got a thermocouple with my multimeter but can't find it. Maybe a meat thermometer as dipstick would be good enough.
You have an old mitsubishi, right?
I'm 100% sure the oil gets over 100°C in normal use in all the small petrol engines during summer.
Thanks, reassuring. There does seem to be some disagreement on that (the presentation and other posters) but perhaps its less important than the presentation implies anyway (see above).
Might try and measure it. I got a thermocouple with my multimeter but can't find it. Maybe a meat thermometer as dipstick would be good enough.
There's debate on BITOG over what "oil temperature" is.
If it's bulk, measured near the drain plug then it may well not get over 100C. If it's gallery, maybe not either.
But the big ends and pistons will be well and truly up there, so the oil will regularly be exposed to those temperatures...stuff slung around the piston underside with be hot, well atomised (lots of surface area), and swept with blowby gasses...good mechanisms for moving water out of the oil (also where I reckon varnish is created).
type K down the dipstick, right where the oil is draining back from the moving assembly after 10 mins on the highway, it's rare for my Caprice to show under 100C...105 is pretty typical (and that's after about 10 mins).
If it's bulk, measured near the drain plug then it may well not get over 100C. If it's gallery, maybe not either.
But the big ends and pistons will be well and truly up there, so the oil will regularly be exposed to those temperatures...stuff slung around the piston underside with be hot, well atomised (lots of surface area), and swept with blowby gasses...good mechanisms for moving water out of the oil (also where I reckon varnish is created).
type K down the dipstick, right where the oil is draining back from the moving assembly after 10 mins on the highway, it's rare for my Caprice to show under 100C...105 is pretty typical (and that's after about 10 mins).
Originally Posted By: Shannow
But the big ends and pistons will be well and truly up there, so the oil will regularly be exposed to those temperatures...stuff slung around the piston underside with be hot, well atomised (lots of surface area), and swept with blowby gasses...good mechanisms for moving water out of the oil (also where I reckon varnish is created).
Hmmm...as I said above, I think the presentation is talking up (and perhaps misrepresenting) the problem, but it is quite a complex system, and the overall equilibrium probably won't be solely determined by the best-case-micro-climate you describe.
Those hot, wet, oily gases are going to some kind of filter where the oil will be recovered and incidentally perhaps cooled, so some water may re-enter the oil there.
I'd guess bulk oil temperature as measured in the sump might be the best predictor of water accumulation, though the relationship is likely to be variable.
Originally Posted By: Shannow
type K down the dipstick, right where the oil is draining back from the moving assembly after 10 mins on the highway, it's rare for my Caprice to show under 100C...105 is pretty typical (and that's after about 10 mins).
Thanks, reassuring. Might try it on mine if the thermocouple ever turns up.
But the big ends and pistons will be well and truly up there, so the oil will regularly be exposed to those temperatures...stuff slung around the piston underside with be hot, well atomised (lots of surface area), and swept with blowby gasses...good mechanisms for moving water out of the oil (also where I reckon varnish is created).
Hmmm...as I said above, I think the presentation is talking up (and perhaps misrepresenting) the problem, but it is quite a complex system, and the overall equilibrium probably won't be solely determined by the best-case-micro-climate you describe.
Those hot, wet, oily gases are going to some kind of filter where the oil will be recovered and incidentally perhaps cooled, so some water may re-enter the oil there.
I'd guess bulk oil temperature as measured in the sump might be the best predictor of water accumulation, though the relationship is likely to be variable.
Originally Posted By: Shannow
type K down the dipstick, right where the oil is draining back from the moving assembly after 10 mins on the highway, it's rare for my Caprice to show under 100C...105 is pretty typical (and that's after about 10 mins).
Thanks, reassuring. Might try it on mine if the thermocouple ever turns up.
Originally Posted By: Shannow
...
type K down the dipstick, right where the oil is draining back from the moving assembly after 10 mins on the highway, it's rare for my Caprice to show under 100C...105 is pretty typical (and that's after about 10 mins).
Are you inserting that thermocouple deep enough to reach into the top of the sump oil, or is it in the gases (blowby+make-up air+oil mist?) and perhaps oil draining down from the head, i.e., above the sump oil? I suppose there might be a large difference in temperature a few minutes after a cold start.
...
type K down the dipstick, right where the oil is draining back from the moving assembly after 10 mins on the highway, it's rare for my Caprice to show under 100C...105 is pretty typical (and that's after about 10 mins).
Are you inserting that thermocouple deep enough to reach into the top of the sump oil, or is it in the gases (blowby+make-up air+oil mist?) and perhaps oil draining down from the head, i.e., above the sump oil? I suppose there might be a large difference in temperature a few minutes after a cold start.
Originally Posted By: CR94
Originally Posted By: Shannow
...
type K down the dipstick, right where the oil is draining back from the moving assembly after 10 mins on the highway, it's rare for my Caprice to show under 100C...105 is pretty typical (and that's after about 10 mins).
Are you inserting that thermocouple deep enough to reach into the top of the sump oil, or is it in the gases (blowby+make-up air+oil mist?) and perhaps oil draining down from the head, i.e., above the sump oil? I suppose there might be a large difference in temperature a few minutes after a cold start.
Measuring the dipstick length, and putting the bead right between the full and low level marks. Push it to the bottom of the sump, and lose 10C.
It's pulled straight off the highway, and shut off as it's coming to a stop, leap out and test. Literally a 10 minute highways section will have 90+ at the sump wall, and 100-105 at the dispstick level. Repeat it in "2". which is 4,000RPM rather than 1,700 RPM, and it's 125-135C.
Originally Posted By: Shannow
...
type K down the dipstick, right where the oil is draining back from the moving assembly after 10 mins on the highway, it's rare for my Caprice to show under 100C...105 is pretty typical (and that's after about 10 mins).
Are you inserting that thermocouple deep enough to reach into the top of the sump oil, or is it in the gases (blowby+make-up air+oil mist?) and perhaps oil draining down from the head, i.e., above the sump oil? I suppose there might be a large difference in temperature a few minutes after a cold start.
Measuring the dipstick length, and putting the bead right between the full and low level marks. Push it to the bottom of the sump, and lose 10C.
It's pulled straight off the highway, and shut off as it's coming to a stop, leap out and test. Literally a 10 minute highways section will have 90+ at the sump wall, and 100-105 at the dispstick level. Repeat it in "2". which is 4,000RPM rather than 1,700 RPM, and it's 125-135C.
Yes, with some good load, higher rpms make more heat, but not much of a difference in neutral.
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not true, rpm is the main driver of heat production in the oil, regardless of load.
I have two oil temp senders on my Gen Coupe 2L turbo. I use to have an oil/coolant oil filter adapter heat exchanger too.
One sensor is right after the oil filter, the other is the factory one up in the head by the cam solenoids.
The oil coming out of the filter will be hotter up to about 140F; then the top sensor will run hotter. When cruising the head sensor will be 10-20F hotter than the sump oil. But if you sit and idle then the sump will come up to the head temp.
The heat exchanger would bring the oil temp up pretty quick, usually withing 10 miles in the summer, and also keep it from getting too hot. Coolant temps were 180-185F and the oil seldom got over 200F even in the hottest of summer when highway driving. I'm sure on the track it would get much hotter.
One sensor is right after the oil filter, the other is the factory one up in the head by the cam solenoids.
The oil coming out of the filter will be hotter up to about 140F; then the top sensor will run hotter. When cruising the head sensor will be 10-20F hotter than the sump oil. But if you sit and idle then the sump will come up to the head temp.
The heat exchanger would bring the oil temp up pretty quick, usually withing 10 miles in the summer, and also keep it from getting too hot. Coolant temps were 180-185F and the oil seldom got over 200F even in the hottest of summer when highway driving. I'm sure on the track it would get much hotter.
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