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Out of curiosity do you have a way of knowing the coolant temperature in your car? I am willing to bet the water temperature that your block heater brings your car up to before engine start is much hotter than after 17 minutes of idling.
How many watts is it?
With it being that cold it could be a good idea to block off the grill. Unless it has those active shutters
If -30 degrees outdoors and the car has been plugged in for 3 hours, I imagine that the antifreeze temperature in at the top portion of the radiator will register close to -30 degrees, and perhaps a few degrees warmer, but not by much, in the block near the heater. I am not a physicist, but can tell you that with the car plugged three or four hours, even longer, only the area around the block heater does not have a sort of whitish layer of ice. You can clearly see a portion of the block that does not have ice.
You have to take into account that the block, hoses, the heater itself, and the radiator don’t have a thick layer of insulation, all these parts are in full contact with the cold air. If you touch the heater with your finger it will burn it much like if you touch a light 450-watt light bulb, but the rest of the block is ice cold, except for the heater’s surrounding area. Since the block heater does not have a pump, the antifreeze does not circulate around the motor and the radiator. Besides, the block and the head (s) are not full of antifreeze. The later is found in the passages and around the cylinders.
What the block heater does is to prevent the antifreeze from freezing, something that starts taking place a little below -70 degrees F. So if the antifreeze mixture is 50/50, which is the standard mixture for cold weather sold at the stores, it is good for around -35 degrees. It does not mean, however, that the antifreeze will freeze solid at temperatures much colder than that. Instead it will start jelling, just like #2 diesel fuel does at subzero temperatures. The heater just increases the temperature if the antifreeze in the block by a very few degrees, depending on how cold it is outside (subzero versus above zero).
One can have a custom-made grill cover in several of the shops in town. But when a newer car is parked in the driveway or even idling, it does not matter if the grill is covered or not because most newer cars have electric fans these days. The only time the cover helps is when you are on the roads. I have a custom cover on my 1988 GMC Sierra truck, although it also has an electric fan by the radiator.
If -30 degrees outdoors and the car has been plugged in for 3 hours, I imagine that the antifreeze temperature in at the top portion of the radiator will register close to -30 degrees, and perhaps a few degrees warmer, but not by much, in the block near the heater. I am not a physicist, but can tell you that with the car plugged three or four hours, even longer, only the area around the block heater does not have a sort of whitish layer of ice. You can clearly see a portion of the block that does not have ice.
You have to take into account that the block, hoses, the heater itself, and the radiator don’t have a thick layer of insulation, all these parts are in full contact with the cold air. If you touch the heater with your finger it will burn it much like if you touch a light 450-watt light bulb, but the rest of the block is ice cold, except for the heater’s surrounding area. Since the block heater does not have a pump, the antifreeze does not circulate around the motor and the radiator. Besides, the block and the head (s) are not full of antifreeze. The later is found in the passages and around the cylinders.
What the block heater does is to prevent the antifreeze from freezing, something that starts taking place a little below -70 degrees F. So if the antifreeze mixture is 50/50, which is the standard mixture for cold weather sold at the stores, it is good for around -35 degrees. It does not mean, however, that the antifreeze will freeze solid at temperatures much colder than that. Instead it will start jelling, just like #2 diesel fuel does at subzero temperatures. The heater just increases the temperature if the antifreeze in the block by a very few degrees, depending on how cold it is outside (subzero versus above zero).
One can have a custom-made grill cover in several of the shops in town. But when a newer car is parked in the driveway or even idling, it does not matter if the grill is covered or not because most newer cars have electric fans these days. The only time the cover helps is when you are on the roads. I have a custom cover on my 1988 GMC Sierra truck, although it also has an electric fan by the radiator.
I have my radiator 100% blocked and it helps. I have Coroplast against the radiator and I slipped foam pipe insulation around the grill slats.
I am not using a block heater. It is a heater installed at the lowest point. Cold coolant is heated and it rises. More cold coolant is drawn in. The entire engine is heated this way through the convection circulation. At 3 F the hood was warm to the touch. Now -30 would be interesting.
OK, here goes. Flat spots on tires at way below zero temperatures? Oh yeah, that certainly does happen. Only way to get 'em round again is drive to get the tires warm.
Diesel idling to warm up? Unless either the driver or the engine's electronic management system elevates the idle, that is about the worst thing that a person can do to a diesel engine. Same with extended idling a diesel in bitterly cold weather. Unless the idle is elevated, the engine will cool sufficiently to wet stack. That's asking for big engine trouble. The ONLY exception in light duty truck diesels that I've personally seen to that rule is the 2005-2006 Jeep Liberty CRD's. The CRD engine was built with a "viscous heater." The viscous heater was a belt-driven pump that circulated extremely thick fluid. Pumping that fluid would heat the fluid, which was then run through a heat exchanger to transfer its heat to the engine coolant. This helped to heat or maintain heat in the diesel engine in two ways--the transferred heat from the viscous fluid pump process was one. The other was that the viscous pump put a significant load on the engine. The engine's electronic management system would increase fuel delivery to the engine to maintain idle speed with the viscous pump running, thus creating more heat. Either with the somewhat unconventional viscous heater or the more common elevated idle control on diesel engines, the purpose is the same--cause the engine to burn enough fuel to warm the engine up or keep it warm while idling. (By the way, the recommended elevated idle speed for Ford diesels that are extended idled in extremely cold temperatures is 1,200 RPM, nearly one-third of the way up of the engine's recommended total RPM range.)
In pre-2007 diesel engines, wet stacking was pretty easy to spot in bitterly cold weather. If the exhaust was whitish or blue smoke, it indicated a lot of partially burned fuel being exhausted, a prime indication that the engine was wet stacking. A 2007+ diesel that is wet-stacking can quickly plug the diesel particulate filter because all that soot and partially burned fuel is being trapped in it.
There is no other way in addition to the block heater but idling to warm the motor for the first few minutes, at least in Alaska. Maybe down by your side of the pond tractor-truck, grader, dozer, and other heavy equipment with diesel engines' operators don't let the motor warm-up before driving. But I drove trucks for many years in the lower-48, and back then the trucks had a throttle control in the cab to let the motor warm for several minutes before driving. Nowadays the ECU takes care of the high, medium, and normal idle speeds.
When very cold outside as it was yesterday, the RPM of my car's motor when stopped at the light 20 miles away from home was still 1,000. That's very normal, since the sensors are telling the ECU that the antifreeze plus the intake air are still not warm enough.
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Don't believe me? Go the Caterpillar website and look at the instructions about warming their diesel motors up. Also, do the same for every other diesel motor builder in the planet. While I can agree with you that driving it increases the heat output, in the temperature conditions we experience up here, you better let it idle a few minutes depending on how cold it is before driving it. Now, if you are driving a loaded tractor and can drive the truck slowly on a side road (hopefully a downhill one) before getting on the highway, by all means do so. But it makes no sense whatsoever to merge into highway traffic on a cold motor while towing.
And yes, all kinds of environmental institutions or people will tell you to just drive a diesel truck to warm the very cold motor just after the oil pressure looks good on the gage. But if you read the manufacturer's instructions, you will notice that they recommend a certain warming period that exceeds what the US environmental agencies want you to do. And believe me when I tell you that in extreme wether conditions such as the Dalton Highway in Alaska, you won't see truck drivers turning their trucks off by the side of the road.
One of this days I will come back to this thread and post a photo of the water vapor rising at -20 or -30 from all kinds of vehicles idling at the supermarket parking lot. Drivers just don't turn their trucks off at the stores loading ramps when very cold.
Ray is incorrect about a block heater not heating any area other than close to the heater. One of the main advantages of a block heater is that the coolant can move by convection through the engine as it is heated. The heat won't move into the radiator because the thermostat is closed, but it is moving through, well, the block of the engine. In fact, with many block heaters, one can actually hear the coolant circulating by convection in the block if one listens carefully.
As to extended idling in diesels, I wish people would read what I say. IN A DIESEL ENGINE IN EXTREME COLD CONDITIONS, THERE IS NOT ENOUGH FUEL BEING BURNED AT NORMAL IDLE RPM TO MAINTAIN THE ENGINE AT ACCEPTABLE OPERATING TEMPERATURE, OR NOT ENOUGH FUEL BEING BURNED TO WARM THE ENGINE TO OPERATING TEMPERATURE FROM A COLD START. THE ENGINE MUST BE "INSTRUCTED"--EITHER BY ENGINE'S ELECTRONIC MANAGEMENT SYSTEM, OR BY THE DRIVER--TO BURN MORE FUEL. THE MOST COMMON WAY TO DO THIS IS BY INCREASING ENGINE RPM. IF THIS IS NOT DONE, THE ENGINE WILL COOL TO THE POINT THAT IT CAN NOT PROPERLY COMBUST FUEL, AND "WET STACKING" WILL OCCUR. WET STACKING HAS THE POTENTIAL TO CAUSE SEVERE ENGINE DAMAGE.
I've watched plenty of ignorant truckers from warm climates wreck diesel engines in severe cold by failing to elevate the idle to an RPM sufficient to keep the engine warm. "Sufficient RPM" in this case is usually anywhere from 15%-30% throttle, on the order of 800-1,200 RPM for most truck diesel engines.
On the contrary. I am correct about about a block heater heating mainly the antifreeze and area around the heater, but all depends on ambient temperature and the heater's wattage. I already said that if very cold outside, lets say -35 degrees as the car is plugged into the electrical outlet for three hours and you check the coolant temperature in the top portion of the radiator, more than likely the temperature will be close to -35 degrees. What you haven't realized is that since the whole engine, hoses, and radiator are in close contact with air that's a-35 degrees, these too dissipate a great portion of the heat generated by the heater. But as soon as the motor starts, the pump moves the antifreeze throughout the motor and radiator, including the warmer antifreeze near the heater. On top of that, since heat rises, the oil pan heater has increased the oil temperature very slightly, which in turn helps the pump circulate it through the oil passages. Three hours is not just enough to raise the antifreeze temperature in the radiator very much if very cold outside. And if you don't have a battery blanket or a trickle charger keeping the battery warm or charged, the motor is not going to start, since cold reduces the battery capacity quite a lot.
In relation to diesel motors, you will notice that some very old diesel automobiles are still on the road. A coworker of mine has a very old Mercedes that has a diesel motor with over 200,000 miles, and it's still doing fine. In places where it gets very cold, most drivers don't turn their automobiles off when shopping unless there is an outlet they can plug their vehicles into. Truck drivers do the same on the roads, because it would be stupid to turn the motor off at extreme subzero temperatures. Truck drivers have been letting their trucks' diesel motors idle for long periods for many years already, and it is in recent years that "experts" are telling drivers not to idle their engines. I did it myself when driving tractors with trailers. If you live in a very cold place, take a look at the road graders idling at your nearest DOT work shop, or just take a look at the transit's bus fleet idling before, after, and during shift change.
And yes, maybe a diesel motor could be damaged that way, but if you are on the road and don't have the means to restart your truck's motor at subzero temperatures, maybe only you aren't going to keep it idling. It's only recently that laws are being created to curb big rig idling, by these laws don't apply in Northern Canada and Alaska for obvious reasons. It's just too cold.
The engine warms up a lot faster under load than sitting there idling. I fire up, give it maybe 30 seconds, then drive very gently for the first few minutes. A faster warmup gets things up to operating temperature more quickly and is easier on the engine.
On the contrary. I am correct about about a block heater heating mainly the antifreeze and area around the heater, but all depends on ambient temperature and the heater's wattage. I already said that if very cold outside, lets say -35 degrees as the car is plugged into the electrical outlet for three hours and you check the coolant temperature in the top portion of the radiator, more than likely the temperature will be close to -35 degrees. What you haven't realized is that since the whole engine, hoses, and radiator are in close contact with air that's a-35 degrees, these too dissipate a great portion of the heat generated by the heater. But as soon as the motor starts, the pump moves the antifreeze throughout the motor and radiator, including the warmer antifreeze near the heater. On top of that, since heat rises, the oil pan heater has increased the oil temperature very slightly, which in turn helps the pump circulate it through the oil passages. Three hours is not just enough to raise the antifreeze temperature in the radiator very much if very cold outside. And if you don't have a battery blanket or a trickle charger keeping the battery warm or charged, the motor is not going to start, since cold reduces the battery capacity quite a lot.
In relation to diesel motors, you will notice that some very old diesel automobiles are still on the road. A coworker of mine has a very old Mercedes that has a diesel motor with over 200,000 miles, and it's still doing fine. In places where it gets very cold, most drivers don't turn their automobiles off when shopping unless there is an outlet they can plug their vehicles into. Truck drivers do the same on the roads, because it would be stupid to turn the motor off at extreme subzero temperatures. Truck drivers have been letting their trucks' diesel motors idle for long periods for many years already, and it is in recent years that "experts" are telling drivers not to idle their engines. I did it myself when driving tractors with trailers. If you live in a very cold place, take a look at the road graders idling at your nearest DOT work shop, or just take a look at the transit's bus fleet idling before, after, and during shift change.
And yes, maybe a diesel motor could be damaged that way, but if you are on the road and don't have the means to restart your truck's motor at subzero temperatures, maybe only you aren't going to keep it idling. It's only recently that laws are being created to curb big rig idling, by these laws don't apply in Northern Canada and Alaska for obvious reasons. It's just too cold.
Most block heaters are around 700-800 Watts. Now, I've used 'em in temperatures down to below -50° F. At those temperatures, the block heater likely needs to be plugged in all night. At 20 below, two or three hours is usually sufficient. Now, if it's 40 below outside, a block heater is not going to heat the coolant in the engine sufficiently to open the cooling system's thermostat--so, the coolant in the radiator is going to be at the outside temperature. But the coolant in the engine (and the block) is going to be warmed at least to a temperature to make starting considerably easier. It also means in a diesel that the combustion temperature in the cylinders will rise more rapidly once the vehicle is started.
Now, as to how all of this works in current generation diesel, I'll use the Ford 6.7 that I drive for my work as an example.
First scenario, 20 below zero start with the block heater plugged in for 4 hours prior to starting:
Get in the truck, turn on the ignition, glow plug light comes on for less than 6 seconds. When glow plug light goes out, start the truck, foot off of the accelerator. Within 30 seconds, the engine computer elevates the idle to around 700-800 RPM. OBDII shows coolant temperature above freezing. Idle will remain elevated until coolant temperature is around 80-100° F., then will drop to normal idle (more about this later).
Second scenario, 20 below zero, cold start with no block heater:
Get in the truck, turn on the ignition, glow plug light comes on for 10 seconds or more. When glow plug light goes out, start the truck, foot off of the accelerator. Warning message comes on saying that the vehicle can not be put into gear for 30 seconds. At around 30 seconds, the engine computer elevates the idle, usually to 1,000-1,200 RPM. OBDII shows coolant temperature at near outside ambient temperature. Idle will remain elevated for a considerable period of time, slowly dropping toward normal idle once the engine temperature approaches 100° F.
Once the vehicle has reached operating temperature, if it is stopped and left idling in 20 below temperatures, the coolant temperature will begin to drop almost immediately. If the coolant temperature drops to near 100°, the engine computer will begin elevating the idle to bring the coolant temperature up.
There are two important operational reasons that this elevated idle procedure occurs. The first has been around as long as diesels--to make the engine reach and maintain combustion temperatures sufficient to burn the fuel being injected into the engine. Otherwise, some of the unburned fuel and soot will wash down the cylinder walls into the crankcase, contaminating the engine's motor oil and compromising its lubricating ability. That's wet stacking. The second reason that it is done in current generation diesels is to, as quickly as possible, eliminate unburned fuel and soot from exhausting the engine and lodging in the diesel particulate filter, and to, as quickly as possible, raise the exhaust gas temperature for the same purpose.
Now, here is the problem with the high idle procedure outlined above. It was clearly a compromise by Ford (and the other diesel truck manufacturers do the same thing) to only have the "automatic" high idle work if coolant temperatures are less than 100°--that compromise being engine wear vs. fuel consumption. Raising the idle significantly raises fuel consumption. Using the 6.7 as an example, it will use around 0.3 gallons of fuel per hour at normal idle speed of 600 RPM at normal operating temperature--that for a 6.7 liter V8. By comparison, a 4 cylinder 2.5 liter fuel-injected gasoline engine at full operating temperature will use about 0.2 gallons per hour at idle, only 0.1 of a gallon less than engine more than 2.5 times larger in displacement. Raise the idle speed of the 6.7 to 1,200 RPM and its fuel use will go over a gallon per hour. The compromise is that a diesel engine at 100° F. coolant temperature is going to wet stack some. That is why an optional Elevated Idle Control is necessary in those diesels operated in severe cold--so that the driver can manually "force" a high idle to keep the engine temperature at a level higher than 100°.
A final note, back in the old days, diesels could be extremely difficult to start in cold weather--much more difficult than most modern diesels. (Anyone who has had to start an old Caterpillar dozer with the gasoline "pony" engine--video attached--will know what I'm talking about.) So, leaving diesels running in very cold weather was often a necessity back then. That said, wet stacking would usually shorten their lives considerably when operating in cold temperatures.
Most block heaters are around 700-800 Watts. Now, I've used 'em in temperatures down to below -50° F. At those temperatures, the block heater likely needs to be plugged in all night. At 20 below, two or three hours is usually sufficient. Now, if it's 40 below outside, a block heater is not going to heat the coolant in the engine sufficiently to open the cooling system's thermostat--so, the coolant in the radiator is going to be at the outside temperature. But the coolant in the engine (and the block) is going to be warmed at least to a temperature to make starting considerably easier. It also means in a diesel that the combustion temperature in the cylinders will rise more rapidly once the vehicle is started.
Most block heaters for 4 cylinder motors are around 400 Watts. I was referring to the one on my 2012 Toyota Corolla. The one on my 1988 GMC Sierra with a 350 motor has a 450-watt block heater. Since electricity in Fairbanks is so expensive, what we do is to plug the vehicle to an outdoors electrical timer for about 2 to three hours depending on ambient temperature. If minus -35 or so, then it heats for around 3 hours. At that temperature you can still see ice on the engine block in the areas away from the coolant passages in the block.
Our trucks with diesel motors are plugged to the outlet for around 3 hours when the temperature drops below freezing, perhaps around +20 degrees and colder. Some people install very powerful heaters on their diesel motors, but one has to be very careful since in the interior of Alaska we experience extreme temperature inversions. While a few short hours may not cause problems, a canister heater can overheat if for whatever reason the antifreeze level drops.
Quote:
Now, as to how all of this works in current generation diesel, I'll use the Ford 6.7 that I drive for my work as an example.
First scenario, 20 below zero start with the block heater plugged in for 4 hours prior to starting:
Get in the truck, turn on the ignition, glow plug light comes on for less than 6 seconds. When glow plug light goes out, start the truck, foot off of the accelerator. Within 30 seconds, the engine computer elevates the idle to around 700-800 RPM. OBDII shows coolant temperature above freezing. Idle will remain elevated until coolant temperature is around 80-100° F., then will drop to normal idle (more about this later).
Second scenario, 20 below zero, cold start with no block heater:
Get in the truck, turn on the ignition, glow plug light comes on for 10 seconds or more. When glow plug light goes out, start the truck, foot off of the accelerator. Warning message comes on saying that the vehicle can not be put into gear for 30 seconds. At around 30 seconds, the engine computer elevates the idle, usually to 1,000-1,200 RPM. OBDII shows coolant temperature at near outside ambient temperature. Idle will remain elevated for a considerable period of time, slowly dropping toward normal idle once the engine temperature approaches 100° F.
Once the vehicle has reached operating temperature, if it is stopped and left idling in 20 below temperatures, the coolant temperature will begin to drop almost immediately. If the coolant temperature drops to near 100°, the engine computer will begin elevating the idle to bring the coolant temperature up.
There are two important operational reasons that this elevated idle procedure occurs. The first has been around as long as diesels--to make the engine reach and maintain combustion temperatures sufficient to burn the fuel being injected into the engine. Otherwise, some of the unburned fuel and soot will wash down the cylinder walls into the crankcase, contaminating the engine's motor oil and compromising its lubricating ability. That's wet stacking. The second reason that it is done in current generation diesels is to, as quickly as possible, eliminate unburned fuel and soot from exhausting the engine and lodging in the diesel particulate filter, and to, as quickly as possible, raise the exhaust gas temperature for the same purpose.
Now, here is the problem with the high idle procedure outlined above. It was clearly a compromise by Ford (and the other diesel truck manufacturers do the same thing) to only have the "automatic" high idle work if coolant temperatures are less than 100°--that compromise being engine wear vs. fuel consumption. Raising the idle significantly raises fuel consumption. Using the 6.7 as an example, it will use around 0.3 gallons of fuel per hour at normal idle speed of 600 RPM at normal operating temperature--that for a 6.7 liter V8. By comparison, a 4 cylinder 2.5 liter fuel-injected gasoline engine at full operating temperature will use about 0.2 gallons per hour at idle, only 0.1 of a gallon less than engine more than 2.5 times larger in displacement. Raise the idle speed of the 6.7 to 1,200 RPM and its fuel use will go over a gallon per hour. The compromise is that a diesel engine at 100° F. coolant temperature is going to wet stack some. That is why an optional Elevated Idle Control is necessary in those diesels operated in severe cold--so that the driver can manually "force" a high idle to keep the engine temperature at a level higher than 100°.
A final note, back in the old days, diesels could be extremely difficult to start in cold weather--much more difficult than most modern diesels. (Anyone who has had to start an old Caterpillar dozer with the gasoline "pony" engine--video attached--will know what I'm talking about.) So, leaving diesels running in very cold weather was often a necessity back then. That said, wet stacking would usually shorten their lives considerably when operating in cold temperatures.
I agree that diesel motors are easier to start nowadays, but the rules haven't changed much in extreme cold weather in isolated places that are away from electrical outlets and things like that. Since a diesel motor started in cold wether takes a very long time to warm up, once warm on the road truck drivers don't stop the motor when stopping along the road to take a nap (for example). That truck is left idling for hours at a time.
I drove very old AC road graders. These graders had diesel motors and a 3-speed manual transmission, and didn't have hydraulic systems. But they had a manual throttle control to keep the RPM high enough to allow the motor to warm up for several minutes if not hours before driving, and these motors lasted to the end of time
Here's an issue I have. I'm currently driving a 2012 Nissan Rogue. When cold if I were to just drive off after just 30 seconds, I get a very loud lifter knock. Apparently this is a common trait amongst Nissan's QR25DE motor. Common sense says that the lifter knocking is a result of the engine being cold in conjunction with the oil not having time to fully circulate and make its way to the top of the motor where the lifters are located. Why else would they knock when cold and not when warmed up?
For this reason alone is why I cant see how driving off in the dead of cold after 30 seconds can have no long term negative effect on the internals of an engine. Mine in particular.
I have my radiator 100% blocked and it helps. I have Coroplast against the radiator and I slipped foam pipe insulation around the grill slats.
I am not using a block heater. It is a heater installed at the lowest point. Cold coolant is heated and it rises. More cold coolant is drawn in. The entire engine is heated this way through the convection circulation. At 3 F the hood was warm to the touch. Now -30 would be interesting.
There are magnetic heaters you can use if the engine had an iron block. The block heater on my 1987 Civic Si is bolted to the aluminum block, and the same for a 1994 Suzuki Sidekick. Most of these heaters are made in Canada. When living with -30 and colder temperatures for days or weeks at a time and the temperatures rise to the teens, something that happens in the middle of the winter, it feels like summer to us. If it is -40 for a couple of days, and then the temperature comes up to around -10, it feels real nice outdoors
A lot of people in the lower-48 States are idling their trucks' and cars' motors (diesel or not) for extended periods of time lately, because of the cold fronts moving South from Alaska and Canada.
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