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Are there any write-ups on the difference of time, or lack of difference, it takes for different viscosity oils to get up to operating temperature? My search wasn't very successful. Thanks.
Studies for how long different viscosity oils take to get up to operating temperature.
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That's why I was looking for a standardized study that only changed viscosity. It's okay if it doesn't exist. I was just curious how much viscosity would impact warm-up times, if at all.
There are too many variables to be able to predict that.,,
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Some recently uploaded wear charts from studies show increased wear while oil is not at operating temperature. Decreasing the amount of time spent getting up to temp may have an effect on wear.
Again, this is mostly just curiosity. An interesting thought.
You will in real life never see a difference. The same thing with oil filters yes a better filter is nice but engines well cared for will out last the the rest of the vehicle. It is a numbers game.
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Agree to disagree, there are some truly atrocious engines out there right now that I doubt will outlast the rest of the vehicle.
I'm just curious about any studies on the topic on the thread title. Again, if they don't exist, that's okay.
RPM is a large factor in warming oil and also in the steady state temperature of the oil.
IIRC there's a small window where heat has thinned the oil and AW additives/VII's haven't fully activated. From my own anecdotal experience my oil temp gauge starts moving at the same point in the drive regardless of exterior temps and oil weight (0w30 sub 3.5 HTHS to 5w40 HTHS over 3.5).
Automakers use oil/coolant heat exchangers to raise oil temps as quickly as possible.
You could probably find information on base oil at a fixed viscosity but not on fully formulated motor oils.
It would be interesting to see controlled samples of something like a 10w30 vs a 0w20 being heated at the same temperature to see which sample reaches that temp first.
Been a long time since I took a thermo/fluids dynamic course..
Been a long time since I took a thermo/fluids dynamic course..
But sump temperature would be an outcome of many different factors, right? I doubt a generic answer could be obtained other than a thicker oil will heat up faster than a thinner one and it would be highly dependent on the RPM.
How about in the bearing? Would this help to determine the frictional heating?
How about in the bearing? Would this help to determine the frictional heating?
I think I know the study you're referring to, and in that study, the increased wear was associated with low engine temperature in general (coolant, oil, and everything else), not specifically low oil temperature. The increased wear may be largely related to thermal expansion and tolerances.
In my own experience with datalogging oil and coolant temperatures during engine warm-up on my car, the oil temperature consistently lags the coolant temperature by 12-15 degrees C during engine warm-up, whether the oil is cold and thick or whether it's getting thinner as it nears operating temperature, so I don't think a thicker grade of oil would warm up appreciably faster.
A thicker oil might experience more friction heating generally, but it will have lower flow rates when cold since the oil pump will be in pressure relief. In any case, the difference between grades probably wouldn't be more than 1 or 2 degrees.
The best way to minimize engine wear during engine warm up is to use a block heater. Oil pan heaters are a lot less effective. Using a grill block in cold weather can help as well, but it makes a rather small difference during the early stages of warm up when most of the wear is occurring.
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I’m more curious on how long they take to cool down, all external factors being equal. Hot oil sitting in a hot turbo can leave a varnish/deposits, so I assume an oil that cools faster would be less prone to this. I’m sure there is a similar effect around piston rings.
Would an oil that gets up to temp ___f be less prone to fuel dilution too? If the tipping point for fuel deposits to stabilize and start to burn/evaporate off is arbitrarily say 200f, then an oil that hits 200f (all factors being equal) would stop taking on fuel sooner, no?
Would an oil that gets up to temp ___f be less prone to fuel dilution too? If the tipping point for fuel deposits to stabilize and start to burn/evaporate off is arbitrarily say 200f, then an oil that hits 200f (all factors being equal) would stop taking on fuel sooner, no?
No matter what oil or other treatment a poorly built or designed engine will be a poorly designed or built engine. I worked for 23 years at a forklift dealership and we maintained lots of pickups , vans sweepers etc and most of the peoples preconceived notions are just that. There is all the stuff that seems to make sense and is written up about but in real life produces no real benefit.
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This makes sense to me. I need to separate oil temperature from overall engine temperature.
So a well cared for engine can die before the rest of the vehicle, which is contradictory to what was said earlier. That's what I was getting at.
Again, for the third time, this is all just hypothetical. I don't think X viscosity heating up Y faster is going to save my engine another Z thousand miles. This is just a curiosity I had based on another study that was posted.
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A big factor would be any heat exchanger on the oil-coolant which might keep fluids tracking to similar temps. If it's an automatic, usually they have an ATF to coolant heat exchanger, and I would think all fluids could come up to temp pretty quickly.
But an older manual trans car with no heat exchangers? Would have to get a datalogger.
But an older manual trans car with no heat exchangers? Would have to get a datalogger.
On my car, the block heater will increase coolant temperature by 33 C and oil temperature by 20 C. The engine will spend less time at the coldest temperatures where wear is highest.
In the chart below, over half of all wear over a 45 minute run occurs within the first few minutes of engine start. A block heater will provide warming equivalent to at least a few minutes of engine operation, so we might expect from this figure that using a block heater would reduce engine wear by over 50% on a 45 minute driving cycle, and potentially reduce wear a lot more than this for shorter driving cycles.
However, I expect it's not that simple. Thermal expansion of the bores may track well with coolant temperature, but the pistons themselves are going to warm up a lot faster than the coolant, and the initial wear rates we see on the piston rings in the first few minutes of engine operation might have a lot more to do with piston temperature (or the relative differences warm-up rates of engine components) than coolant or oil temperature. This is supported by another test from the same study where they manually lowered coolant and oil temperatures below 30 C while the engine was already running, and only observed a doubling of engine wear, and not the ~20x increase in wear rates we see in this chart.
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