alright guys.. any of you FMIC boys have trouble with water temps? obstructs the flow to the rad, just wanted to know if you've had problems or not. anything to write home about?

yep me lol

 

because it goes like this

 

front bumper>FMIC>Air Filter>Oil cooler>A/C fan>A/C rad>radiator

 

thats a hell of a lot to get the air past before it gets to the main engine rad, and i have my viscous / no engine tray / and full fan shroud and the engine temps still creep on idle

 

Though mine is mostly when idling and not when driving. need to get a uprated rad and then remove my A/C rad when i change it over, im keeping my viscous though.

Alot of people ditch the viscous fan as they zap power but for the amount it actually zaps its not worth it, the viscous fans are great at keeping temps down the design is great really

If I understand it correctly, the viscous fan should only really activate at low speed, or say when stationary at lights for example.

Once moving in excess of 30 - 40 mph the air flow developed should then take over and the viscous coupling should disengage, thus allowing the engine to rev more freely. (This will vary slightly depending on the weather I guess)

If the fan is on continuously, or not at all then the shaft in the centre may have seized.

I am a big fan of the the viscous unit, (no pun intended by the way) Mine cuts in when moving slowly in traffic or stationary for a minute. (really audible roar!!)

However, once I get going again she disengages. Brilliant design!

If I understand it correctly, the viscous fan should only really activate at low speed, or say when stationary at lights for example.

Once moving in excess of 30 - 40 mph the air flow developed should then take over and the viscous coupling should disengage, thus allowing the engine to rev more freely. (This will vary slightly depending on the weather I guess)

If the fan is on continuously, or not at all then the shaft in the centre may have seized.

I am a big fan of the the viscous unit, (no pun intended by the way) Mine cuts in when moving slowly in traffic or stationary for a minute. (really audible roar!!)

However, once I get going again she disengages. Brilliant design!

 

Good theory but completely wrong mate. lol The viscous fan is directly related to engine rpm. So when the car is at idle then the fan is also idling. Once you speed up (and the engine is hot enough to activate the fan clutch) the fan will also speed up. This is the reason that a lot of zeds start to overheat on idle. If your hearing an audible roar then it's coming from the backup electric fan on the a/c rad, this kicks in above 100deg to cool the engine down.

 

HTH

Not sure about that Steams, lol.

With the greatest respect, I have to disagree. (unless there are multiple designs that it)

The theory is that the coupling only engages when necessary, thus freeing up Horse Power when disengaged,. (ie when air flow is sufficient enough to out perform the draw of the fan.)

I will try and explain my understanding of how this comes about. At low rpm and when the engine is at normal temperature, lets say at standstill. The cooling system temperature warms the spring assembly in the centre of the coupling, this in turn rotates the valve shaft allowing the viscous medium to travel out wards by way of centrifugal force. This is where the clever stuff happens, as the oil passes through a intricate series of meshing channels, viscous friction is created and therefore drives the fan. The design is such that the air flow created is enough to maintain a healthy temperature under most conditions.

Once moving (say in excess of 30mph) the air flow becomes more efficient than the fan and cools the central spring, thus rotating the shaft so as to close the internal valve. which in turn via centrifugal force removes the oil from within the channels and disengages the coupling.

 

This is only my understanding based on research and having dismantled one so as to understand the internal workings.

The roar that I refered to is definately the viscous fan cutting in when I am at a standstill or moving slowly.

 

I hope I have not caused any offence.

The viscous fan does run all the time if you open the bonnet when on idle it's spinning as it connected to the water pump pulley driven by a belt connected to the crank pulley, if you rev the engine the fan will speed up with the engine rpm, it also runs constant it sucks in loads of air as the fan shroud pulls it towards the engine,

The viscous fan does run all the time if you open the bonnet when on idle it's spinning as it connected to the water pump pulley driven by a belt connected to the crank pulley, if you rev the engine the fan will speed up with the engine rpm, it also runs constant it sucks in loads of air as the fan shroud pulls it towards the engine,

 

it does spin all the time but is not really driven with power until the viscous fan cuts in as described by redwine - being a viscous coupling it is the viscosity of the oil that determins if the clutch cuts in to drive it fully depending on air temps over the viscous coupling from the radiator.

 

if the temp is not hot enough it will be allowed to freewheel to prevent the engine being sapped of power by driving it

 

:)

As you say,

the fan is rotating all the time but is ineffective until the temperature requires the fan to be actively driven. It is mealy revolving due to what light residual friction that is present.

It is not drawing much air in at all

In fact, You can actually stop it with a gloved hand if all is running correctly.

But once the coupling kicks in and the fan is viscously engaged it would be next to impossible to stop!!

it does spin all the time but is not really driven with power until the viscous fan cuts in as described by redwine - being a viscous coupling it is the viscosity of the oil that determins if the clutch cuts in to drive it fully depending on air temps over the viscous coupling from the radiator.

 

if the temp is not hot enough it will be allowed to freewheel to prevent the engine being sapped of power by driving it

 

:)

 

Damn, to slow again.

As you say,

the fan is rotating all the time but is ineffective until the temperature requires the fan to be actively driven. It is mealy revolving due to what light residual friction that is present.

It is not drawing much air in at all

In fact, You can actually stop it with a gloved hand if all is running correctly.

But once the coupling kicks in and the fan is viscously engaged it would be next to impossible to stop!!

 

Yep not spinning that much on idle was just trying to say without writing an essay lol yep stopped one once when was leaning on the slam panel and finger caught the fan lol,

Not sure about that Steams, lol.

With the greatest respect, I have to disagree. (unless there are multiple designs that it)

The theory is that the coupling only engages when necessary, thus freeing up Horse Power when disengaged,. (ie when air flow is sufficient enough to out perform the draw of the fan.)

I will try and explain my understanding of how this comes about. At low rpm and when the engine is at normal temperature, lets say at standstill. The cooling system temperature warms the spring assembly in the centre of the coupling, this in turn rotates the valve shaft allowing the viscous medium to travel out wards by way of centrifugal force. This is where the clever stuff happens, as the oil passes through a intricate series of meshing channels, viscous friction is created and therefore drives the fan. The design is such that the air flow created is enough to maintain a healthy temperature under most conditions.

Once moving (say in excess of 30mph) the air flow becomes more efficient than the fan and cools the central spring, thus rotating the shaft so as to close the internal valve. which in turn via centrifugal force removes the oil from within the channels and disengages the coupling.

 

This is only my understanding based on research and having dismantled one so as to understand the internal workings.

The roar that I refered to is definately the viscous fan cutting in when I am at a standstill or moving slowly.

 

I hope I have not caused any offence.

 

of course you haven't mate, it's all healthy discussion :)

That's basically what I was saying tho' (albeit, in a far better way than I did lol) about the engine temp being high enough to activate the viscous clutch. The belt that drives the fan runs at the same speed as the engine as it's running the water pump too, so there isn't a difference in horsepower regardless of whether the fan is running or not.

Nice one mate.

 

Still have to beg to differ there with you though. oops. (lol)

It is argued that when the coupling is fully engaged it takes that little bit more horse power to drive the fan as opposed to when it is free wheeling.

May only be 1 or 2 HP but it was felt that every little counts.

Something to do with the higher degree of torque required to draw the massive amount of air.

A little bit like when the air conditioning compressor is disconnected for a few seconds during full throttle.

 

Sorry johnp1984, we seem to have drifted away from your original post.

Edited July 21, 201213 yr by redwine300

Nice one mate.

 

Still have to beg to differ there with you though. oops. (lol)

It is argued that when the coupling is fully engaged it takes that little bit more horse power to drive the fan as opposed to when it is free wheeling.

May only be 1 or 2 HP but it was felt that every little counts.

Something to do with the higher degree of torque required to draw the massive amount of air.

A little bit like when the air conditioning compressor is disconnected for a few seconds during full throttle.

 

Sorry johnp1984, we seem to have drifted away from your original post.

 

 

Your probably right mate don't think you would really notice it though ;)

I think as long as you've got a thicker rad, and if you remove the aircon rad ect you'll be fine,

 

I've got a thick rad will be running a front mount aswell aircon rad and fan removed and probably stick with viscous fan and may chuck in an electric fan to aid things

A viscous fan can pull 5hp...........:blink:

A viscous fan can pull 5hp...........:blink:

 

Id rather lose the HP than risk the Over heating, i know some people take it off, but after what I've had with cooling problems, i prefer it there as peace of mind.

Id rather lose the HP than risk the Over heating, i know some people take it off, but after what I've had with cooling problems, i prefer it there as peace of mind.

 

Deffo, after all, if it is working correctly you only ever loose horse power during slow traffic or at standstill

Other than then there is no loss of power. Winner winner.

hi guys been looking at faq on overheating but cant open the document in there my na is overheating on idle and at revs and fans running

help please weathers good and I want to take her out

http://z32.wikispaces.com/Cooling+System

 

try that matey, helped me a bit, not the best but might help you pin point it, considering the part is so cheap and its relatively easy to do, might be a good idea to start at the thermostat.

that page is SO handy! also, vodkashots, where in northants are u? i'm over in wellingborough :)

up queensway matey, your in wellingborough now? grab me number give me a bell

Edited July 22, 201213 yr by vodkashots

thanks vod will have a look

A viscous fan can pull 5hp...........:blink:

 

Blimey! didn't think you'd be losing as much as that. Still better than the 300 odd you would lose if the engine overheated though. lol

rang my breaker mate and he has got one as well as a water pump not so bad after all

small world :) cant believe we both live on queensway lol.. about 1/4 mile away :)