Radiator Fan Clutch

[Lukas]

Predictably, I've been playing with this after I pulled it out in preparation for turning the engine. Observations:

• The clutch is initially quite stiff, but you can turn the fan independently of the clutch with a little effort
• If you do turn the fan independently of the clutch, the clutch frees right up
• Leave it for a while and you're back to square 1

Anyone know if this is how it should be? The fan operates fine while the vehicle is idling, can't say for when warmed up or under load.

The fan was quite greasy after I pulled it out, so it hit it with the pressure cleaner. Subsequently noticed (weeks later) that it was dribbling a little fluid, so (thinking that water had gotten in) pulled the little circular metal disc off to reveal a bearing race and some goop. Cannot get the allen bolts off the back of the clutch loose at all (dissimiliar metals = very rusty); so can't pull it apart completely.

Does anyone have any experience in cleaning the innards out (including or excluding the viscous clutch itself)? I am tending towards "it works, leave it alone you idiot".

Ta

Lukas

 

[abl567]

Make sure you store it vertical, like when it is installed. Then it shouldn't leak

 

[Tony66_au]

Honestly?

If you are not fussed about originality id replace the clutch fan with thermo fans, Summit racing in the US have an excellent range of high flow fans and accessories at a more then reasonable price.

 

[Oversize]

Check if the clutch locks when the engine's hot. If it's not leaking badly after a while (clean it and store it vertically) and the engine hasn't been overheating, then I'd re-use it and spend your money on other improvements...

 

[Styria]

Hi Lukas, when they're leaking a very special oil that's almost impossible to procure, you can safely say that the unit is defective and should be replaced/rebuilt. There are two types of units - one rebuildable which has the Allen headed screws (bolts), whilst the other is a throwaway job. I have rebuilt units over time, but unless you know what you're about, don't touch it. It is a difficult and time consuming job

The special oil provides the necessary drag, and it is my understanding the way to test the unit is to switch off the engine when hot and observe the fan. If it keeps on turning, or if there is no drag resistance, the unit is not doing its job. Presently, if I remember correctly, I have one rebuilt unit on hand, but will only exchange it for a unit with the aforementioned Allen headed bolts. New ones are very expensive - several hundred dollars last count. Regards Styria

 

[Lukas]

Thanks Styria - it is the allen headed variant, but 5 out of the 6 or 8 bolts are firmly rusted on. It seemed to be working correctly at last check, will check it again on Sunday to be sure.

 

[Tony66_au]

Clutch fans have always been a dark art and I have great respect for those who repair them, Thanks for the heads up on checking for issues Gents and especially to you Styria for your simple check.

 

[Styria]

Tony, I just had to start improvising, if that's the right word, on account of the cost of spare parts, plus apparent lack of supply of parts. Really, it was the cost of parts. When I bought Gleaming Beauty sixteen or seventeen years ago, I paid a 'steal price' of $10750.00 which was about $11K. below any other 6.9 advertised. As I said, that was cheap. I think the dealer was scared of the car, plus it had a transmission that flared from second to top (quoted $3.5K. to repair - it lasted for five years), it needed three front air cells but I well remember paying then (at that time) $90.00 for the rubber hose from rocker cover to air filter. $90.00 ! Regards Styria

 

[WGB]

Unfortunately the only way I have ever tested them is with teh motor running.

On a 450 motor - get it hot and idling, in neutral.

Slowly raise the engine speed with the bonnet open and you will hear the fan roar increase until at about 3,000 or so rpm (the spec is given in the manual) it will suddenly cut out with click and the fan roar will cease and you will only hear the engine revs increasing.

Not much use as a test if your motor isn't running.

Bill

 

[Oversize]

You may find the engine doesn't get hot enough to activate the engine fan (or electric thermofans) and it may be necessary to block airflow through the radiator with a big sheet of cardboard. But not a good idea to try it when racing at Bathurst; just ask Moffat!!! Check out 2:37mins:

http://www.youtube.com/watch?v=73j0jdg-ayQ&feature=related

 

[Tony66_au]

Tony, I just had to start improvising, if that's the right word, on account of the cost of spare parts, plus apparent lack of supply of parts. Really, it was the cost of parts. When I bought Gleaming Beauty sixteen or seventeen years ago, I paid a 'steal price' of $10750.00 which was about $11K. below any other 6.9 advertised. As I said, that was cheap. I think the dealer was scared of the car, plus it had a transmission that flared from second to top (quoted $3.5K. to repair - it lasted for five years), it needed three front air cells but I well remember paying then (at that time) $90.00 for the rubber hose from rocker cover to air filter. $90.00 ! Regards Styria

A great Greek bloke name of Plato once said "Necessity is the mother of invention".

And he was correct, I've bodged and dodgied a few things over the years purely because the "right" way involved lots of expense but I've also learned skills I never thought id need fixing stuff in the middle of the night so I could drive to work in the morning.

For my money a $150 thermo fan would do the job but I still admire those with the tenacity to nut out those things that others would run from.

 

[Tony66_au]

Unfortunately the only way I have ever tested them is with teh motor running.

On a 450 motor - get it hot and idling, in neutral.

Slowly raise the engine speed with the bonnet open and you will hear the fan roar increase until at about 3,000 or so rpm (the spec is given in the manual) it will suddenly cut out with click and the fan roar will cease and you will only hear the engine revs increasing.

Not much use as a test if your motor isn't running.

Bill

LOL in which case Styria's method comes into play.

 

[Lukas]

Obligatory pic: