mart
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can anybody tell me how the viscous fan on a 200tdi works and how to tell if its knackered, thanks mart
viscous fan
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Simon72
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The fan clutch is an automatic device that is often used in a vehicles cooling system. So, when the engine is cool or even when it is at a normal operating temperature, the fan clutch will partially disengage the engines radiator cooling fan (which is mechanically driven).
This is normally found at the front of the waterpump and it is driven by a belt and pulley that is connected to the engines crankshaft This process will then save power because the engine wont have to fully drive the fan.
But, if the engines temperature gets hotter than what the settings for the clutch are, the fan will then become fully engaged, this will then maintain or even lower the temperature of the engine.
You will find that most fan clutches are viscous or fluid (the internal friction of a fluid that is produced by movement of its molecules against each other. It is what causes the fluid to resist flowing) couplings that are combined with a bi-metallic (its a strip that is used to convert a temperature change into mechanical displacement and it usually consists of two layers of iron and copper) sensory system that is similar to that in a thermostat.
Sometimes fan clutches will fail on you but they are normally quite reliable so this doesnt often happen. You will find though that a common symptom of the clutch fan failure is the car overheating when idling.
If you have a bad fan clutch, it can also cause very poor performance in the vehicles air conditioning system. The reason for this is because the fan also cools the air conditioners condenser and that is found directly in front of the radiator.
The other potential symptom if the fan clutch fails is that it will draw the air at a very high rate, so in the cold weather the heating system will blow out lukewarm air and it wont ever deliver enough sufficient hot air.
It is best to leave the replacing of the fan clutch up to a professional mechanic, unless of course you know what you are doing. But if you are finding that the vehicle is fine on the highway, yet when you are in traffic or you are stuck at a red light and the heat gauge immediately goes up and gets too hot, then it may be time for you to get it replaced.
It is quite a simply process as the fan clutch is simply sandwiched between the can and the connecting shaft. All that would have to be done is to unbolt the fan and remove the clutch. The new one is then installed and the fan re-attached and you will then be on your way. It is advisable to may be do a coolant flush and put in a new thermostat at the same time.
This is normally found at the front of the waterpump and it is driven by a belt and pulley that is connected to the engines crankshaft This process will then save power because the engine wont have to fully drive the fan.
But, if the engines temperature gets hotter than what the settings for the clutch are, the fan will then become fully engaged, this will then maintain or even lower the temperature of the engine.
You will find that most fan clutches are viscous or fluid (the internal friction of a fluid that is produced by movement of its molecules against each other. It is what causes the fluid to resist flowing) couplings that are combined with a bi-metallic (its a strip that is used to convert a temperature change into mechanical displacement and it usually consists of two layers of iron and copper) sensory system that is similar to that in a thermostat.
Sometimes fan clutches will fail on you but they are normally quite reliable so this doesnt often happen. You will find though that a common symptom of the clutch fan failure is the car overheating when idling.
If you have a bad fan clutch, it can also cause very poor performance in the vehicles air conditioning system. The reason for this is because the fan also cools the air conditioners condenser and that is found directly in front of the radiator.
The other potential symptom if the fan clutch fails is that it will draw the air at a very high rate, so in the cold weather the heating system will blow out lukewarm air and it wont ever deliver enough sufficient hot air.
It is best to leave the replacing of the fan clutch up to a professional mechanic, unless of course you know what you are doing. But if you are finding that the vehicle is fine on the highway, yet when you are in traffic or you are stuck at a red light and the heat gauge immediately goes up and gets too hot, then it may be time for you to get it replaced.
It is quite a simply process as the fan clutch is simply sandwiched between the can and the connecting shaft. All that would have to be done is to unbolt the fan and remove the clutch. The new one is then installed and the fan re-attached and you will then be on your way. It is advisable to may be do a coolant flush and put in a new thermostat at the same time.
Trewey
Cockernee, Pasty munchin bastid.
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in english, and without the benefit of copy and paste....
when the engine is cold, you should be able to spin the fan easily with your fingers. when hot, it should be stiff.
of course, test it with the engine off, unless you've fallen out with your fingers.
if you decide to remove it, it's a left hand thread.
when the engine is cold, you should be able to spin the fan easily with your fingers. when hot, it should be stiff.
of course, test it with the engine off, unless you've fallen out with your fingers.
if you decide to remove it, it's a left hand thread.
discool
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Well done Treworgey 90 that answers the question exactly.
Parragraph 6 is incorrect for the disco ie. if you have a bad fan clutch, it can also cause very poor performance in the vehicle’s air conditioning system. The reason for this is because the fan also cools the air conditioner’s condenser and that is found directly in front of the radiator.
A disco's a/c condenser is cooled by twin electric fans located together with the condenser in front of the radiator the condenser is not cooled by the engine fan.
Parragraph 6 is incorrect for the disco ie. if you have a bad fan clutch, it can also cause very poor performance in the vehicle’s air conditioning system. The reason for this is because the fan also cools the air conditioner’s condenser and that is found directly in front of the radiator.
A disco's a/c condenser is cooled by twin electric fans located together with the condenser in front of the radiator the condenser is not cooled by the engine fan.
Pikey
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I like them fans tho - will they fit a standard rad?
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Read trewys post
Trewey
Cockernee, Pasty munchin bastid.
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J.P.S
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Also check ya thermostat! Mine was like this until it it had a new stat! As the the one fitted had stuck fully open! After the new stat the temp needle went straight to the middle, up hill n down dale! Oh and the heater worked proper
They bolt onto the air con rad frame and cover the rad and also the intercooler. They could be fitted with a bit of minor iron work.
I did use them as a back up on my airconditioned 200tdi when I took off my engine driven fan. But to be honest I hardly ever need them, in fact I am think of taking off the leccy one I have fitted and wiring the leccy air con ones to a thermostat switch.
regards
Dave
J.P.S
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Thanks to boomerv8 i got rid of my viscous fan today! I removed my aircon a lil while back but left fans in situ for when needed as they do seem to shift a fair bit of air themselves!
