Getting a radiator that functions appropriately is crucial to having a car that continues to function correctly. Water pump is a single of the important parts of the cooling program of a vehicle. A fan’s job is to pull air through some thing, this some thing will eventually develop a restriction or a pressure drop. This can also be the issue if the gauge stays low and the auto by no means heats up. If the temp gauge is reading low but the two radiator hoses are warm, the temp sensor may not be operating. This variety of radiator is specifically great for people with dust allergies as their flat panel tends to make them effortless to clean and they do not “convect” heat or market air circulation to heat a space these elements support to reduce the quantity of dust being circulated about a room. The extreme heat generated by the car can just burn of your engine, which will eventually result in the breakdown of the car. Our variety of fans can be utilized for cooling radiators, oil and transmission coolers, condensers, evaporators, heaters, CAC’s, batteries, and ventilation. When seeking in to the issue of the overheating of a vehicle, the air conditioning compressor needs the cooling fan functioning in idle mode as long as the car’s compressor is on. To check if the car’s cooling fan is functioning, the air conditioner has to be switched on. Its switches on collectively with the car’s air conditioner compressor. As the vehicle moves, the air entering by means of the grille of the automobile cools down the heated antifreeze contained in the radiator. Natrad has a full variety of functionality cooling parts, such as fans that supply crucial air flow to engine working under stress. 1,591 car radiator fan stock photos, vectors, and illustrations are obtainable royalty-totally free. Puller-style fans are recommended for applications in which the electric fan is the major cooling supply. I explained that each and every cooling program component was new, and that the technique had been bled numerous occasions. SpeedComfort can even be utilized with electric, cast-iron and designer radiators by utilizing the Clip-On Feet to raise the SpeedComfort 25mm (1in) off the floor below your radiator. I have been a huge fan of zoned heating from the likes of Genius , but this does not support the efficiency of the radiator in every room. At this time, verify the tightness of the fan belt and no matter whether the fan blades are deformed or broken. GM Original Gear Engine Cooling Fan by ACDelco®. The fan then begins blowing air across the radiator thereby complementing the waterbased-cooling of the radiator. The liquid coolant that passes through the engine absorbs all the heat developed, keeping the engine temperature beneath control. The fan clutch system saves horsepower from the engine by taking away unneeded drag. All automotive radiators, no matter whether in cars, trucks, buses and tractors, use the same principle although functioning. The auxiliary fan assembly is discovered straight in front of the radiator and blows chiller outdoor air previous the radiator fins. Directing water to circulate only by way of the engine allows the engine to attain optimum operating temperature as speedily as feasible whilst avoiding localised “hot spots.” As soon as the coolant reaches the thermostat’s activation temperature, it opens, allowing water to flow by way of the radiator to stop the temperature increasing larger. Solution Note: Electric Fan Kit – Universal Fit Principal cooling fan. Below is numerical information of a SPAL fan showing what is called, in the cooling market, a fan curve. Thus the hot antifreeze coolant carries the engines’ waste heat from the engine straight into the radiator where the air flowing (or drawn by the functioning rad fan) expelling, diluting and exhausting waste excess heat from your vehicles’ motor into the nearby air. To quit the engine from overheating , we take the aid of coolants that flow by way of a radiator into the engine. Most reliable mechanics would recommend that any time your radiator requirements repair that you replace it. The expense difference is not wonderful unless you’re repairing the radiator yourself, and your probabilities of obtaining to make the repair again in the future are mineralized. The fan in most automobile models is installed in front of the radiator. On pre 1991 Jeeps with no a radiator cap, it is valuable to get rid of the temperature sensor at the back of the head to let the air escape. When you find an internal leak in the cooling technique, do an internal leak test by making use of a stress tester to check if there is any combustion gas leakage. Heat is the quantity 1 enemy of mechanical components and even if auto engine’s is designed to deal with these outstanding high temperatures, if these levels get out of handle, the engine will undoubtedly break.
Care ought to be taken to make sure that the flow of the coolant is not hampered by any obstruction. Replace yours as soon as attainable and keep away from overheating or damaging your engine. Interestingly on the other hand, automotive cooling systems are not almost as crucial to the operating and ongoing maintenance of diesel engines. Under we have offered a summary of the electric heating possibilities obtainable on the industry detailing their pros and cons to support you pick which choice is the ideal for your property. If the fan fails to come on, it can cause the engine to overheat. Then the fluid is circulated by the water pump unit, through the channels of your engines’ heavy metal block, by means of the rubber coolant hoses, which you ought to be simply spotted when peering into your engine compartment. On direct air-cooled engines this is not a concern for the bellows thermostat that controls a flap valve in the air passages. The radiator-cooling fan is specially created in such a way that it turns on when the temperature of the engine rises and stops when the temperature is normal. The writer explains that in order for vehicle radiators in North Hollywood to get in as a lot coolant as car engines want, the hoses conveying the fluid should be large enough tightening the nozzles or joints also assists enhance efficiency by stopping leaks. They all have the very same standard function, which amounts to drawing in further air, but specifically at low rpm circumstances and instances when the car sits at an idle. Logically, however, the cooling fan keeps the cooling method at the optimal temperature to stop the hotter than normal engine temperatures, as pointed out above. An early approach was to take benefit of an aircraft’s abundant airflow to replace the honeycomb core (many surfaces, with a high ratio of surface to volume) by a surface mounted radiator. You should make it your every day habit to verify the coolant levels in your radiator. These coolant hoses pass from their fitting on the engine eventually to the radiator. More merely they may be oil-water coolers, where an oil pipe is inserted inside the water radiator. This will lessen the effective back-stress against the flow of air, and at the limit of its efficiency will minimise the likelihood of the air stalling through the compressor blades. If the radiator does not have cool air blowing on it consistently, it will overheat ultimately, so you’d need the perfect combination of weather and traffic to drive successfully with no a radiator fan. SpeedComfort, a radiator fan, claims to improve the radiator heating power by 20% decreasing the warm-up time by 50% and lowering bills by 22%. Getting a green cord for your cabinet cooling fan can support make positive that you only use your fan when it is needed, for that reason employing less energy and creating some important savings. A TYC Auxiliary Fan Assembly aids a radiator in lowering the excessive heat of the antifreeze. Most electric fans come equipped with thermal-sensors that activate the fan when it reaches a hot temperature. Furthermore, you will uncover the anti-freezing coolant dripping in to a modest puddle beneath your car. The fact that radiator pipes are narrow means it takes less time for the antifreeze to cool down. This was a key limit on performance in the course of the 1930s when the introduction of turbosuperchargers first permitted convenient travel at altitudes above 15,000 ft, and cooling style became a significant area of research. Design of Fan blades and Motor Assistance ribs in RFM is crucial to increase Flow noise, i.e. Air cutting noise. You also need to check and recognize any external leaks and damages to any of the elements of the cooling technique that contain the water pump, radiator, engine coolant passages, heater hoses and heater core. If we’re speaking what do you do with a restricted space, there is also constantly the choice to run fans on both sides of the radiator in series. The fan clutch is accountable for holding the fan to the engine and turning it. If this assembly burns, you would have to replace it with a new 1. Inside the cooling technique, the coolant is sealed and it is under stress and that is why, in these circumstances, the coolant will boil at around 120 degrees Celsius. Set up the new radiator, with fan assembly, into the vehicle. The radiator fan does not operate permanently but only when the temperature switch, connected to the radiator indicates a rise in temperature above a certain set level.
Correct coolant levels: Guaranteeing that the coolant is always topped up will help the radiator run smoothly. Aside from your radiator spewing coolant all over the place, the other typical concern of an overheated engine is your head gasket. Now, I do a lot of work rejuvenating air conditioning systems in vintage vehicles, and as portion of that, it is frequent to replace the condenser and its fan with the largest ones that’ll match. This makes it extremely considerably crucial that you select a cooling fan that greatest suits the specifications of your vehicle. Improvement in high-overall performance aircraft engines required enhanced coolants with higher boiling points, leading to the adoption of glycol or water-glycol mixtures. The radiator fan cools the engine even though the condenser fan increases air-conditioning while the car is at low speed. The coolant, which is a mixture of anti-freeze and water, is the one that absorbs the heat from the engine. If the engine is overheated, verify that the thermostat is working properly. As opposed to standard electrical heaters, oil radiator heaters do not have such a high danger of causing electrical harm. If you have a front wheel drive auto, it possibly has an electrical fan. Just before condemning the fan for a cooling technique related problem, verify the shroud for cracks and missing pieces that could minimize airflow by way of the radiator. When the temperature has reached a specific level – hot enough to trigger damage to electronics – the cooling fan will turn into activated and will work to bring the temperature down. Quite a couple of authorities say it really is a fantastic notion to replace the fan clutch on the very exact same time because the water pump in case the water pump has failed. The coolant absorbs the heat type the engine, even though the radiator dissipates heat. 5. Remove the fans from the radiator. Fans- Titan Kukri H PWM fans – I picked these fans simply because they had a excellent RPM range and I believed would far better represent 25mm fan performance over utilizing 38mm fans. Even so, pressurized systems have been also much more complex, and far far more susceptible to damage – as the cooling fluid was beneath pressure, even minor damage in the cooling system like a single rifle-calibre bullet hole, would lead to the liquid to swiftly spray out of the hole. The Crystalfontz is then employed to monitor fan RPMs and adjusted to a very good stable level and all 17 of the thermal sensors are also turned on to start off recording air in, air out, water in, water out more than those 17 sensors and the fan RPM. The auxiliary fan assembly increases air flow around the radiator so that the engine coolant is properly cooled. For a water cooled method, this means that the maximum quantity of heat transfer is restricted by the particular heat capacity of water and the distinction in temperature amongst ambient and 100°C. After at optimum temperature, the thermostat controls the flow of engine coolant to the radiator so that the engine continues to operate at optimum temperature. Selecting an electric radiator fan is a matter of matching the right-sized cooling fan and radiator combo for your engine. Maintain recommended levels of coolant in the radiator and service the engine on periodic basis to bless this pair and in turn you will get a blessed automobile. On demand heaters are usually utilised with typical, non-Economy electricity tariffs, which do not use cheaper evening-time rates. The ECU signals the radiator fan to work at the precise time. If you have paid interest to the physics classes in high college, you may keep in mind that a radiator is a heat exchanger and its purpose is to transfer the heat from one element of the technique (in our case the engine) to one more portion (the radiator fins). Electric cooling fans may not operate since of a malfunctioning switch, undesirable fan relay, defective fan motor, or faulty control module. The centrifugal clutch has to rely upon the speed of the engine to engage or disengage it. As the engine speeds up, the clutch enables the fan to partially slip, giving back that engine the power it would have used if permanently attached. Under peak load situations, such as driving slowly up a steep hill while heavily laden on a hot day, the thermostat will be approaching totally open due to the fact the engine will be generating near to maximum energy although the velocity of air flow across the radiator is low. This tiny radiator, and the linked blower fan, is called the heater core , and serves to warm the cabin interior.
Consequently, a vehicle owner can make sure that the radiator operates efficiently by permitting the coolant to flow via it properly. The Bosch auxiliary cooling fan assists to preserve the engine cool and prevents overheating. With the physique drenched in perspiration, the fans can quickly trigger it to dissipate and bring coolness to the body. My Nissan np200 heater does not blowing warm or hot air i ‘ve even changed the old thermostat and replace with new one but still the same please assist. Electric fans are controlled by a thermostatic switch or the engine control unit Electric fans also have the advantage of providing good airflow and cooling at low engine revs or when stationary, such as in slow-moving visitors. As the coolant passes by way of the little tubes, it transfers the heat it has absorbed to the blowing air from the grille. The program is filled with distilled water and allowed to bleed and fans allowed to warm up. Then the variac is turned on to apply heat load and dialed in to 100W and the fans are adjusted to 640RPM. Anytime the engine would start, the radiator fan would start off spinning. Aircraft with liquid-cooled piston engines (normally inline engines rather than radial) also demand radiators. When repairing such kinds of leakages in this critical automotive element, it is advised you let the vehicle cool down fully. Electric convectors typically consist of a hollow case open at the leading and bottom with a visible coil heating element. Oil filled radiators have several advantages more than typical heaters that make them safer, and more effective. The driver will know when the automobile is on the limit of overheating by seeking at that plastic bottle and removing the radiator cap. It is drawn by the water pump from the radiator and is pumped via engine block and the cylinder head to absorb the heat from the engine and its components. Although they do nevertheless need to have to be plugged into a wall to draw energy, the amount is only about one particular fourth of what a standard electric heater would use. Oftentimes the temperature can be regulated by a constructed in thermostat, and they often have programmable timers enabling you to switch the heater on and off anytime it is needed to do so-even if you are not yet at property. SpeedComfort is Europe’s ideal-promoting radiator fan for boosting the warmth from your heating program and is currently assisting 50,000+ homes to keep warm and save energy. The automotive engine of the car produces a large quantity of heat that can be severely damaging for the engine and its components. Overheating is not one-sided dilemma but it mainly final results from common motives. Although engines are created to withstand higher temperatures and stress, if this takes place on a constant basis then engine damage is imminent and that means either an end to your car or a large hole in your wallet. Puller-style fans mount behind the radiator and draw air by means of the core. The purpose behind this is that a cooling fan is essential to maintain electronics cool -if electronics are not cooled down successfully then they will at some point turn into broken, and will do so at an improved price if the cooling fan is ineffective. If applicable, reinstall the air conditioner condenser, radiator core and automatic transmission cooler hose. ACDelco GM Original Equipment Fan Blades are made to maintain the correct airflow to the radiator, which keeps your engine from overheating. Electric fans have their positive aspects when it comes to tiny import and compact cars, exactly where size is the primary consideration. Engine Cooling Fan Motor by 4 Seasons®. It is a lot energy effective than your air conditioning or heating system in your property. ACDelco GM Original Gear Fan Assemblies are created to preserve the suitable air flow through the radiator, which keeps your engine from overheating. Without this crucial cooling program of your “power-plant”, the heat constructed up from the exploding gasoline vapors (in a gas engine), would soon overheat and eventually ruin your engine. If you are seeking for that best engine cooling fan, you happen to be in the right location. This fan will begin automatically when your car is warm or when the air conditioning is turned on. The best way to check it is to start off your vehicle and turn on the air conditioner. Overheating issues are typically a non-problem, in spite of how dramatic” the smoke coming out from beneath the hood appears. Enjoy exclusive access to the complete variety of fan clutches, engine cooling fans and fan assemblies from all makers.
An aircraft radiator contained in a duct heats the air passing through, causing the air to expand and obtain velocity. Engine-driven fans are frequently regulated by a fan clutch from the drivebelt, which slips and reduces the fan speed at low temperatures. The cooling fan does not have a clearly defined service life. This makes use of a single surface blended into the fuselage or wing skin, with the coolant flowing via pipes at the back of this surface. Many aircraft had been built employing their style and set quite a few performance records, notably the Heinkel He 119 and Heinkel He 100 Nevertheless, these systems needed many pumps to return the liquid from the spread-out radiators and proved to be extremely hard to hold operating effectively, and were much a lot more susceptible to battle damage. A single of the benefits of electric fans is they come in all types of different sizes from slimmer profiles to these with diverse widths and heights. As the coolant spreads over the leading of the radiator tubes, it transfers heat to the air. Unbolt the fan shroud from the cross member and slide it back more than the mechanical fan but do not eliminate it. Use care not to loose the clips that the fan shroud and electric fan bolt to. If they break or get lost, you can get replacements at most hardware shops. If you happen to be adding an electric fan as an auxiliary cooling source you can use a pusher style. An additional consideration for men and women who may possibly be concerned with excessive fan noise is the blade shape, this is where s-blade electric fans come in compared with straight bladed fans. In a automobile, motor oil is pumped throughout the engine block to lubricate the components, but this is insufficient to overcome the tremendous heat generated. Overall and to summarize the cooling program of your vehicle – be it vehicle, truck, or SUV does precisely what its name suggests – it removes, reduces and fundamentally its function is to get rid of heat from your engine method expelling this waste heat into the nearby air. Thermal kind cooling fan clutch There are two basic sorts of fan clutches: thermal and non-thermal (also termed torque limiting”). Engines need to have heat to operate effectively, but require powerful cooling—especially in efficiency applications—to eradicate as significantly power-robbing heat as achievable. This is known as the Meredith impact , and higher-performance piston aircraft with nicely-developed low-drag radiators (notably the P-51 Mustang ) derive thrust from it. The thrust was significant adequate to offset the drag of the duct the radiator was enclosed in and allowed the aircraft to accomplish zero cooling drag. Auxiliary fan assemblies enhance the circulation of cold air by means of the car’s coolant method, particularly when the car is idle. There are two types of fans, electric and mechanical. They occasionally run following the engine has been shut off to bring the temperature back to normal specifications. In addition, most fan clutches are thermal, so they engage and disengage according to air temperature to make sure the automobile will not get overcooled. Interestingly, storage heaters were initially created during the strikes of the late seventies and there is an argument that the government encouraged their use at this time as they had been keen to maintain the power stations running to make the nation dependent on the coal industry. The fins conduct heat from the tubes and then transfer it to the air flowing through the radiator. Driven by a pulley (like the manual fan), the insides of the clutch has fluid that produces internal friction that couples with a bi-metallic sensor comparable to a thermostat. This implies that fan heaters will blast warm air into a space quite speedily, but as soon as they are turned off, the space will cool virtually quickly. If there is a problem with it, you will not be able to turn the fan blade effortlessly when the vehicle is off and the engine is cold. The following 3 types of electric heating consume electrical energy “on demand” in contrast to storage heaters. When factors go from poor to worse, and your broken radiator fan causes a disastrous overheating episode, you may possibly have no other selection but to get a replacement for your radiator unit. The cooling fan relay is typically under the hood. It must cool the antifreeze that circulates by means of the block and head passages and reduces the engine temperature. If the fan is not working even when the automobile is heating up there may be a issue with the wiring.
Hence, the radiator fans come into picture. I fairly significantly took off the complete carb except for a couple hoses that have been real pains in the asses… But sooner or later, following sufficient fiddling and prodding of the cable, I realized it was simply a sticky return spring, just visible behind the top cooling fin of the cylinder. If you are getting troubles with automobile cooling, your neighborhood Natrad can perform a cost-free cooling program inspection, and diagnose the cause of the dilemma. Exactly where engines are mid- or rear-mounted, it is typical to mount the radiator behind a front grill to obtain enough airflow, even although this needs long coolant pipes. The computer software provides true-time fan warning alerts when functionality operating problems have manage panel of the failed fan will be grey out,so you can quickly determine which fan is causing problems. Radiator fluid need to be flushed and replaced every single two years on most automobiles to prevent corrosion in the cooling system. Summit Racing carries a massive choice of electric radiator fans to comprehensive your cooling method upgrade. Cost-powerful to run, the energy-saving Radfan prevents unnecessary heat loss by quietly re-directing warm air into the centre of the space, leaving you feeling cosier and saving you pennies at the same time. A vehicle radiator is a heat-exchanging device that keeps the engine cool by obtaining rid of excess heat by means of the radiation approach. Right here at Merlin we stock a wide range of electric cooling fans. Prior to Globe War II, engine coolant was usually plain water. The need to have for evaporative cooling was soon to be negated by the widespread availability of ethylene glycol based coolants, which had a decrease certain heat , but a much greater boiling point than water. Most oil filled radiators have a cut of switch for overheating, electrical overload, and tip more than accidents. For over 55 years, Hayden Automotive has been the leader in overall performance cooling goods for transmission, engine and energy steering oil cooling. Your auxiliary fan assembly brings fresh outdoors air into the radiator to increase the cooling procedure. Cleaning methods for radiators, boilers, and electric-heater fans. As the radiator cools the fluid, the coolant becomes denser and falls. Nowadays nearly every application requires radiators fans. An auxiliary fan assembly draws cool exterior air via the radiator to speed up the reduction of heat. Related to pumps this increases the pressure capability and especially excellent for dense radiators. As airspeed is greater than for automobiles, these are efficiently cooled in flight, and so do not require big regions or cooling fans. Electric radiators are typically regarded as becoming one hundred% efficient as nearly one hundred% of the electricity consumed by the radiator is converted into heat and released into the area. The ECU is accountable for starting the radiator fan once the engine gets hot. The non-thermal (torque limiting) fan clutch does not possess a temperature sensing capability. Some car radiators last a couple of years even though other folks final decades. Now to move the fan to the other side and see what takes place when the fan is pushing air via the radiator. Building, tubing, airflow and expense are some of the factors that impact the radiator. The function of the radiator is to decrease the temperature of the hot coolant that passes from the engine and to send it back to the engine by means of hoses, thermostat and water pump. The bigger the radiator, the huge amount of heat it can eliminate from the engine. The clutch fan is comprised of a disk-like housing that forms the hub of the fan, and sits in front of the water pump. Soon after parking the automobile for 15 20 minutes with ac on its engine temperature goes to half and ac trips and radiator fans are off. It is secure to perform a leak verify when the vehicle is cold and the engine is switched off. There are fairly lightweight low-profile fans, and thicker, heavier high-performance fans. It is usually a limitation of most cooling systems that the cooling fluid not be allowed to boil, as the require to handle gas in the flow drastically complicates design. This is exactly where a cooling technique becomes necessary in a automobile. Yes, technically your engine does not need a cooling fan to operate. Step 6: Lift the radiator away from the engine, producing sure to have some towels or a catch basin underneath the radiator to catch any remaining coolant still inside the radiator. We’re supplying a Cost-free Cooling Technique Check as thanks for deciding on us. T&Cs apply.
This may sound like a significant advantage, but any time you repair a radiator, you decrease its capacity to cool. We can provide a wide variety of quality SPAL axial cooling fans , centrifugal blowers and related accessories at competitive costs all obtainable with worldwide delivery. Electric radiator fans are available in each pusher and puller designs. Contact Kirk’s Auto Care in Livonia, MI, at 734-402-8722 to talk about your radiator fan problems. Even so, when I drove the vehicle to the Lotus Owner’s Gathering (LOG) in August, in spite of my obtaining installed a switch to straight turn on the fan and not rely on the temperature sensor, the car overheated in dramatic fashion even though I was waiting in the queue to get into the concour, held at Thompson Motor Speedway in Connecticut. Heat transfer from the radiator to the condenser can alter efficiency, if the vehicle is overheating. To enhance air flow through the radiator – in an effect to get a lot more cooling power out of your rad method a fan draws air by means of the fins or tubes on the radiator itself. To do this keep the radiator cap open, commence the automobile, and put the heat on max. A radiator fan is hence used to preserve the temperature of the coolant in verify. Radiators in North Hollywood cars nonetheless face a danger of experiencing meltdown, even regardless of the comparatively reduced temperatures of fall and winter. These radiators have been not as robust as contemporary radiators, nor did they cool as well as contemporary radiators. The GTs just have a special fan blade that appears to bury almost all air type noises into the radiator which is good, but it also tends to have a tiny bit of bearing whine and the motor noise is present perhaps a bit much more than other fans. This post aims to give clear info and details to aid you choose the electric heating solution that very best matches your distinctive lifestyle and heating wants. Nonetheless, frequent overheating episodes are indicators that there is some thing wrong with your cooling technique. We checked to be certain the front-mounted radiator fan was spinning the appropriate way. The radiator transfers the heat from the fluid inside to the air outside, thereby cooling the fluid, which in turn cools the engine. Auxiliary fan assemblies enhance the circulation of cool air into the car’s cooling method, particularly at instances when the car is stopped. This way, the second rad acted as an Airbreak” in front of the fans and I could see how much of an effect this would have on temperatures. As the heated coolant moves from the engine block to the radiator, it gets cooled simply because of the aluminum body of the radiator that dissipates the heat. Prior to coolant was employed, water was poured into radiators. Radiators first used downward vertical flow, driven solely by a thermosyphon effect. It ought to open and enable coolant to pass once the engine is adequately heated. 12. Bleed the cooling method to ensure that all air pockets are removed. There are also mesh designs of fan guard for your electronics or cabinet cooling fan, which can be valuable also depending on your particular demands. RadFan works a little differently due to the fact it blows the warm hair horizontally into the space, with the aim to avoid it cooling as the air passes over the cold window. The engine delivers energy to run the automobile but it is the radiator that maintains the health of the engine. I can not comment on actual efficiency overall performance, it would take months of testing, but as far as heating efficiency goes, there is absolutely an improvement. Significantly less commonly, energy steering fluid, brake fluid, and other hydraulic fluids might be cooled by an auxiliary radiator on a car. The radiator has tubes that contain massive quantity of water and has fin area to permit outside air to pass via. Automotive radiators have been instrumental in maintaining the heat created beneath handle. Routine checks can aid in sustaining the vehicle’s cooling technique. The location of the radiator is of extreme significance permitting it to perform its principal function i.e. cooling the engine. Radiator caps for pressurized automotive cooling systems. Solution Note: Cooling Fan Assembly with Shroud – Consists of handle module. Firstly as a belt driven fan is only going to spin as rapidly as your engine low end rpm cooling abilities so is not quite as great as it would be with an electric fan exactly where the airflow is far more consistent. When the engine is switched off, the cooling system cools and liquid level drops.