More beneficial: Block or Oil heater?
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I'd say block. Even if you ran hot oil through a frozen block, the thermal mass of the block (say 50 kilos) is greater than that of the oil (say 5 kilos) so the oil would cool down first as the block takes up some of that heat and then start heating up.
block. water holds a lot more heat than oil does, so it is more efficient to heat the block, due to chemistry, physics and mathematics.
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Oil heater. Better to have the oil flow easily, allowing the engine to start more reliably and protect the components at the same time. The coolant will warm up readily enough as long as the engine's thermostat is functioning as it should.
Not much good for the engine having a lukewarm water jacket and a couple pounds of thick syrup sitting in the pan.
A block heater might be better for the occupant waiting for the heater to produce heat, but the engine is better served with an oil pan heater in severe cold.
Not much good for the engine having a lukewarm water jacket and a couple pounds of thick syrup sitting in the pan.
A block heater might be better for the occupant waiting for the heater to produce heat, but the engine is better served with an oil pan heater in severe cold.
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Originally Posted By: paul246
Oil heater. Better to have the oil flow easily, allowing the engine to start more reliably and protect the components at the same time. The coolant will warm up readily enough as long as the engine's thermostat is functioning as it should.
Not much good for the engine having a lukewarm water jacket and a couple pounds of thick syrup sitting in the pan.
A block heater might be better for the occupant waiting for the heater to produce heat, but the engine is better served with an oil pan heater in severe cold.
by that argument we should all be using oil heaters in summer
wouldn't a block heater help the oil to "defreeze" a bit anyway
Oil heater. Better to have the oil flow easily, allowing the engine to start more reliably and protect the components at the same time. The coolant will warm up readily enough as long as the engine's thermostat is functioning as it should.
Not much good for the engine having a lukewarm water jacket and a couple pounds of thick syrup sitting in the pan.
A block heater might be better for the occupant waiting for the heater to produce heat, but the engine is better served with an oil pan heater in severe cold.
by that argument we should all be using oil heaters in summer
wouldn't a block heater help the oil to "defreeze" a bit anyway
Both!!!
Oil pan heater would be better. A Block heater heats the coolant, which decreases it's service life if done too often. The Oil pan heater on the other hand heats the oil for better lubrication and does add some gentle heat to the rest of the engine. A friend of mine that uses a magnetic oil pan heater can start his car with 10w30 in our brutal cold Canadian winters like it was a hot summer day. He has heat within a few minutes too. He runs his 2-3 hours before he leaves the house.
I have advocated for the oil pan being better in the past. Oil lubricates, coolant only prevents overheating, not a problem durring the first moments of engine operation. Modern EFI doesnt need help correctly metering and atomising fuel like old carbs did. Also the block should warm up faster than the oil during running because that is were the fire is.
Heating the oil is better. If it's cold enough you may not really need a cooling system much, if at all. Warm oil will help to start the engine by allowing easier cranking with less starter drain on battery. This keeps ignition supply voltage higher important even on electronic ignitions. The hardest thing to do is strart it up once going your coolant will heat up faster than the oil will usually.
Originally Posted By: crinkles
Originally Posted By: paul246
Oil heater. Better to have the oil flow easily, allowing the engine to start more reliably and protect the components at the same time. The coolant will warm up readily enough as long as the engine's thermostat is functioning as it should.
Not much good for the engine having a lukewarm water jacket and a couple pounds of thick syrup sitting in the pan.
A block heater might be better for the occupant waiting for the heater to produce heat, but the engine is better served with an oil pan heater in severe cold.
by that argument we should all be using oil heaters in summer
wouldn't a block heater help the oil to "defreeze" a bit anyway
I don't quite understand where you are coming from on your first line of the reply???
I guess if you are talking our summer it would be your winter... and how cold does it get on average in NSW?
As far as the OP question, he wants to know what is best for an engine in the case of extreme cold. There is no doubt that an oil pan heater is the best of the two choices. Thats why heavy equipment operators use them in the depth of winter on things such as log skidders and dozers etc.
Originally Posted By: paul246
Oil heater. Better to have the oil flow easily, allowing the engine to start more reliably and protect the components at the same time. The coolant will warm up readily enough as long as the engine's thermostat is functioning as it should.
Not much good for the engine having a lukewarm water jacket and a couple pounds of thick syrup sitting in the pan.
A block heater might be better for the occupant waiting for the heater to produce heat, but the engine is better served with an oil pan heater in severe cold.
by that argument we should all be using oil heaters in summer
wouldn't a block heater help the oil to "defreeze" a bit anyway
I don't quite understand where you are coming from on your first line of the reply???
I guess if you are talking our summer it would be your winter... and how cold does it get on average in NSW?
As far as the OP question, he wants to know what is best for an engine in the case of extreme cold. There is no doubt that an oil pan heater is the best of the two choices. Thats why heavy equipment operators use them in the depth of winter on things such as log skidders and dozers etc.
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It's an unanswerable debate. While some study allegedly showed that heated oil won in a hot oil:cold engine vs. cold oil hot engine wear study, what the study called hot and cold aren't necessarily in the realm that we're questioning (while the oil may have been 200F ..the engine was probably 70F).
That warm oil is going to be out of the picture in about about a minute or two. There's no way to retain heat when you're passing through a -20F mass with that much conductive cold potential (lack of heat).
Take something like a diesel air compressor with a 150F outlet air temp running 100Ft of 1" flexible line in single digit(f) temps (85psi outlet pressure). By the time you reach the end, the air mass had shrank to so low a cfm to make it unusable. This is not the case with oil flow ..but the effect of thermal loss is what I'm referring to.
I can't see the oil NOT losing so much in the cycle through the engine not to dip WAY down in sump temp ...as in cool sump ..still stone cold block.
So, I have to reason (and this is all reasoned opinion) that the benefits of an oil heater are lost in the first few seconds of operation (call it a couple of minutes, if you desire), while the block heater would carry everything EXCEPT the starting event.
I'd put my money on thin oils and a block heater. The fuel enrichment cycle is the real killer to most engines.
Naturally, both would be ideal.
That warm oil is going to be out of the picture in about about a minute or two. There's no way to retain heat when you're passing through a -20F mass with that much conductive cold potential (lack of heat).
Take something like a diesel air compressor with a 150F outlet air temp running 100Ft of 1" flexible line in single digit(f) temps (85psi outlet pressure). By the time you reach the end, the air mass had shrank to so low a cfm to make it unusable. This is not the case with oil flow ..but the effect of thermal loss is what I'm referring to.
I can't see the oil NOT losing so much in the cycle through the engine not to dip WAY down in sump temp ...as in cool sump ..still stone cold block.
So, I have to reason (and this is all reasoned opinion) that the benefits of an oil heater are lost in the first few seconds of operation (call it a couple of minutes, if you desire), while the block heater would carry everything EXCEPT the starting event.
I'd put my money on thin oils and a block heater. The fuel enrichment cycle is the real killer to most engines.
Naturally, both would be ideal.
Back before I ever heard of 5w30, I read a study that blamed the oil for hard cold starts. Now that most of us are running 5W- of 0W-, maybe heating the oil isn't as important.
Originally Posted By: StevieC
A friend of mine that uses a magnetic oil pan heater can start his car with 10w30 in our brutal cold Canadian winters like it was a hot summer day. He has heat within a few minutes too. He runs his 2-3 hours before he leaves the house.
Does your friend live near you? Hamilton's record minimum is -37C. That's not really very cold. We see that regularly, and my father used 10w30 for decades with only a block heater. Below -40C? Yep, it still starts.
He's using 5w30 synthetic now. Maybe he'll make the jump to 0W someday.
Originally Posted By: paul246
There is no doubt that an oil pan heater is the best of the two choices. Thats why heavy equipment operators use them in the depth of winter on things such as log skidders and dozers etc.
I have doubts. The heavy equipment operators are probably using 15W40 or even straight 30 oil in their equipment, so an oil pan heater is essential for them. A block heater warms the coolant within the block, while the oil pan heater warms the metal surface, so I think much more heat would be transferred to and retained by the block with a block heater. That's the most important factor, IMO, provided the oil can still flow well.
A friend of mine that uses a magnetic oil pan heater can start his car with 10w30 in our brutal cold Canadian winters like it was a hot summer day. He has heat within a few minutes too. He runs his 2-3 hours before he leaves the house.
Does your friend live near you? Hamilton's record minimum is -37C. That's not really very cold. We see that regularly, and my father used 10w30 for decades with only a block heater. Below -40C? Yep, it still starts.
He's using 5w30 synthetic now. Maybe he'll make the jump to 0W someday.
Originally Posted By: paul246
There is no doubt that an oil pan heater is the best of the two choices. Thats why heavy equipment operators use them in the depth of winter on things such as log skidders and dozers etc.
I have doubts. The heavy equipment operators are probably using 15W40 or even straight 30 oil in their equipment, so an oil pan heater is essential for them. A block heater warms the coolant within the block, while the oil pan heater warms the metal surface, so I think much more heat would be transferred to and retained by the block with a block heater. That's the most important factor, IMO, provided the oil can still flow well.
My friend lives more or less where I do. In another city, but would be around the same temperatures... His car doesn't make any noise with the heater on...
Ideally, both heaters will provide an excellent solution. If the weather is cold enough to justify using engine heaters, it may be cold enough to invest in both types. If I had to choose only one I would go with the block heater. If it's cold enough to plug in, it's probably cold enough to use synthetic oil.
Starting a cold soaked car in -40c weather gives me the same feeling as running finger nails down a blackboard. If the battery is weak or the car is sensitive to cold, it may not start at all. Diesels are particularly bad when cold soaked, it seems the block is so cold that it absorbs all the heat produced by compression and they can be nearly impossible to start without spraying quick start, which can be dangerous to the engine. A friend's RX-8 also wouldn't start when it got below around -35c.
The block heater puts a little warmth in the block and it always turns over faster for me after using the block heater. My battery is strong and I don't use a battery heater so I'm thinking that without a block heater it gets cold enough that moving parts no longer fit well and there's a lot of friction, making it hard to turn.
The block heater also helps the car get up to temperature much faster, giving you heat for defrosting windows etc. It's easier on the engine and the fuel injection will run much better after the engine reaches temp - so it's further beneficial.
I think hot oil will likely be cooled right off to the engine block's cold soaked temperature as soon as it gets pumped through the frozen iron mass.
If you're worried about oil viscosity - which you should be at extreme cold - use synthetic.
Starting a cold soaked car in -40c weather gives me the same feeling as running finger nails down a blackboard. If the battery is weak or the car is sensitive to cold, it may not start at all. Diesels are particularly bad when cold soaked, it seems the block is so cold that it absorbs all the heat produced by compression and they can be nearly impossible to start without spraying quick start, which can be dangerous to the engine. A friend's RX-8 also wouldn't start when it got below around -35c.
The block heater puts a little warmth in the block and it always turns over faster for me after using the block heater. My battery is strong and I don't use a battery heater so I'm thinking that without a block heater it gets cold enough that moving parts no longer fit well and there's a lot of friction, making it hard to turn.
The block heater also helps the car get up to temperature much faster, giving you heat for defrosting windows etc. It's easier on the engine and the fuel injection will run much better after the engine reaches temp - so it's further beneficial.
I think hot oil will likely be cooled right off to the engine block's cold soaked temperature as soon as it gets pumped through the frozen iron mass.
If you're worried about oil viscosity - which you should be at extreme cold - use synthetic.
Originally Posted By: rpn453
Originally Posted By: StevieC
A friend of mine that uses a magnetic oil pan heater can start his car with 10w30 in our brutal cold Canadian winters like it was a hot summer day. He has heat within a few minutes too. He runs his 2-3 hours before he leaves the house.
Does your friend live near you? Hamilton's record minimum is -37C. That's not really very cold. We see that regularly, and my father used 10w30 for decades with only a block heater. Below -40C? Yep, it still starts.
He's using 5w30 synthetic now. Maybe he'll make the jump to 0W someday.
Originally Posted By: paul246
There is no doubt that an oil pan heater is the best of the two choices. Thats why heavy equipment operators use them in the depth of winter on things such as log skidders and dozers etc.
I have doubts. The heavy equipment operators are probably using 15W40 or even straight 30 oil in their equipment, so an oil pan heater is essential for them. A block heater warms the coolant within the block, while the oil pan heater warms the metal surface, so I think much more heat would be transferred to and retained by the block with a block heater. That's the most important factor, IMO, provided the oil can still flow well.
Actually, they would likely run Esso XD-3 0w30 or 0w40 synthetic HDEO or similar and still use pan heaters. Start-up drag is greatly reduced with hot oil.
The point being the oil will readily pump up through the galleries, that is what is most important, doesn't matter if it cools down for a bit, its the fact that oil is present where its required when those engines first start running and while they warm up. That is what extends engine life.
I also agree that both devices would be best, but its best if the oil can flow readily on start in severe cold.
A large amount of heat is still transferred upward into the block as well. Ever try the emergency engine heater?... a bare light bulb or trouble light has a very measurable effect. If its windy place a wall of carboard underneath the vehicle to contain that precious heat.
Bush pilots regularly drained the engine oil from their plane and took it inside with them to keep warm and reinstall it when required. Extends engine life greatly and of course will make it much easier to start.
Originally Posted By: StevieC
A friend of mine that uses a magnetic oil pan heater can start his car with 10w30 in our brutal cold Canadian winters like it was a hot summer day. He has heat within a few minutes too. He runs his 2-3 hours before he leaves the house.
Does your friend live near you? Hamilton's record minimum is -37C. That's not really very cold. We see that regularly, and my father used 10w30 for decades with only a block heater. Below -40C? Yep, it still starts.
He's using 5w30 synthetic now. Maybe he'll make the jump to 0W someday.
Originally Posted By: paul246
There is no doubt that an oil pan heater is the best of the two choices. Thats why heavy equipment operators use them in the depth of winter on things such as log skidders and dozers etc.
I have doubts. The heavy equipment operators are probably using 15W40 or even straight 30 oil in their equipment, so an oil pan heater is essential for them. A block heater warms the coolant within the block, while the oil pan heater warms the metal surface, so I think much more heat would be transferred to and retained by the block with a block heater. That's the most important factor, IMO, provided the oil can still flow well.
Actually, they would likely run Esso XD-3 0w30 or 0w40 synthetic HDEO or similar and still use pan heaters. Start-up drag is greatly reduced with hot oil.
The point being the oil will readily pump up through the galleries, that is what is most important, doesn't matter if it cools down for a bit, its the fact that oil is present where its required when those engines first start running and while they warm up. That is what extends engine life.
I also agree that both devices would be best, but its best if the oil can flow readily on start in severe cold.
A large amount of heat is still transferred upward into the block as well. Ever try the emergency engine heater?... a bare light bulb or trouble light has a very measurable effect. If its windy place a wall of carboard underneath the vehicle to contain that precious heat.
Bush pilots regularly drained the engine oil from their plane and took it inside with them to keep warm and reinstall it when required. Extends engine life greatly and of course will make it much easier to start.
How many watts are avaliable from each?I go with a 1200 watt block heater.
My engine is over 1000lbs dressed, that is a lot of iron to warm and soak out any heat that a pan heater is trying to input(half or which blows into the open air under the truck).
My engine is over 1000lbs dressed, that is a lot of iron to warm and soak out any heat that a pan heater is trying to input(half or which blows into the open air under the truck).
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