[whincup]

im in need of a new fan after i snapped a blade in a water crossing and had it go through the radiator on my last 4x4 trip in my sierra. with that happening, id rather a thermo fan. just wondering if anyone can show me some pictures of how they've mounted their thermo fans, or links to where i can get some ideas... i've spent about an hour on here looking for ideas and cant really find anything since most pics are of engine swaps and nothing radiator or fan specific...
i've wired it so that power gets to the relay when the ignition is turned on, and a manual on-off switch that when left off, a buzzer goes off so i cant forget to turn it back on. (yet to get a fan or a buzzer, but the relays, switch and wiring are all in place)

also, did sierras ever come stock with a clutch fan? went into repco the other day about trying to get a stock fan so i can still drive until i get the thermo set up, they apparently only have clutch fans listed. Standard sierra engine

[Jazzor]

The buzzer sounds like a good idea!, i have left mine off once or twice by accident :/.

I just cable tied mine to my radiator. But some thermo fans/radiators i've seen some with special cable ties. They have a flat block one one end with some padding under, and on the other end there is another wider block with some padding that cable tied up to pressure. I assume this spreads out the load.

Lets see if i can find a pic...


I have a auto cooler cable tied to one side and the thermo fan cable tied to the other side of my radiator. Pretty snug and no movement yet. I also put the cable ties around the heat spreader bits, not around the tubes that hold the water in case they do rip out.

Heres one of the other side:

Most thermo fans I've seen on ebay sit in a shroud that allows them to sit flat on something.

[Reubs]

whincup wrote:

also, did sierras ever come stock with a clutch fan? went into repco the other day about trying to get a stock fan so i can still drive until i get the thermo set up, they apparently only have clutch fans listed. Standard sierra engine

AFAIK only coilies are the only Sierras which came standard with clutch fans.

[Gwagensteve]

Why not bolt up a vitara clutch fan and call it good?

Steve

[BlueSuzy]

x2

[neofitou]

[TheOtherLeft]

neofitou wrote:

What's with the coiled wire next to the top radiator hose?

[Fatzook]

Thermatic fan controller. Tells the fan when to turn on and off based on the coolant temp in the tip hose.

[Shandy]

I'm looking to instal a thermo as well for the same reason, but instead of making an arragement to over ride for water crossings and the like, i figured just put it on the front of the radiator. the blades will pull away form the radiator and you cant leave it off. Its not as eficant and there is probaly a really good reason i haven't seen it done.

[Gwagensteve]

Shandy wrote:

I'm looking to instal a thermo as well for the same reason, but instead of making an arragement to over ride for water crossings and the like, i figured just put it on the front of the radiator. the blades will pull away form the radiator and you cant leave it off. Its not as eficant and there is probaly a really good reason i haven't seen it done.

A) the loss of efficiency is the reason you haven't seen it done. Pushers are common as "helper" fans for A/C etc, but they aren't suitable as a primary fan.

B) are you sure putting the fan in front of the radiator won't stop the blades hitting the radiator? I think the blades will still be pulled towards the radiator so the risk is the same. I've had a good think about this and I'm pretty sure I am right.

I don't understand the fascination with thermos. Removing a simple, effective device and replacing it with a more complex and less effective device seems silly.

Kind of like running a smaller alternator to make more power or something.

Steve.

PS I have thermos, but It's pretty hard to run a mechanical fan behind the cab. They are also out of the mud.

[whincup]

Gwagensteve wrote:

Why not bolt up a vitara clutch fan and call it good?

Steve

I want to be able to turn it off before water crossings, otherwise id leave the stamdard sierra one in. Neverhad an issue with overheating with that...

As for cable ties, are they done through the fins of the radiator? Im not real keen on that, would the constant bumps and vibrations weaken the zip ties over time?

[Jackson]

Gwagensteve wrote:

A) the loss of efficiency is the reason you haven't seen it done. Pushers are common as "helper" fans for A/C etc, but they aren't suitable as a primary fan.

Mine is mounted on the front, due to the fact there is no room on the back, flog it all day long on the beach with no problems.

Gwagensteve wrote:

B) are you sure putting the fan in front of the radiator won't stop the blades hitting the radiator? I think the blades will still be pulled towards the radiator so the risk is the same. I've had a good think about this and I'm pretty sure I am right.

A fan on the front set to push through the radiator would be pulling itself into anything infront of it so I think the blades would flex away from the radiator? Maybe I am thinking the wrong way around?

whincup wrote:

As for cable ties, are they done through the fins of the radiator? Im not real keen on that, would the constant bumps and vibrations weaken the zip ties over time?

I got a pack of the proper mounting things from a radiator place, most places probably have a set lying around. Or you will get a set with most thermos.

Yeah they go between the fins. I have cut a fan off a radiator where it was using these cable tie type things and the fins were hardly damaged. I have seen worse with people using bolts to hold them on. It doesn't really matter if you damage some fins that are covered anyway its the tubes you want to be careful of.

However you mount it the most important thing to do is make sure you get it tight so that the fan doesn't rub or slap on the radiator.

And most importantly get a decent fan.

[Fatzook]

whincup wrote:

I want to be able to turn it off before water crossings,

This is one of the 2 reasons I use thermos in sierras. The other is that I mount the engines 50-100mm lower than standard mounts allow, so the engine driven fans are nowhere near where they need to be to line up with the shroud.

If you buy a GOOD fan, and use a thermo controller with manual over ride for water crossings, you should get plenty of trouble free motoring.

[christover1]

Does a clutch fan stop spinning if it hits water?

[Fatzook]

christover1 wrote:

Does a clutch fan stop spinning if it hits water?

Viscous fans will stop if you chuck your hand in their path, so water should stop them too I would imagine...

[christover1]

Fatzook wrote:

christover1 wrote:

Does a clutch fan stop spinning if it hits water?

Viscous fans will stop if you chuck your hand in their path, so water should stop them too I would imagine...

Thanks, I'll take your word on that,
not brave enuff to test that.
Thats good tho.
One less thing to do during engine instal.

[Fatzook]

christover1 wrote:

Fatzook wrote:

christover1 wrote:

Does a clutch fan stop spinning if it hits water?

Viscous fans will stop if you chuck your hand in their path, so water should stop them too I would imagine...

Thanks, I'll take your word on that,
not brave enuff to test that.
Thats good tho.
One less thing to do during engine instal.

They can sieze though. Not good for the hand then

[JrZook]

Fatzook wrote:

christover1 wrote:

Does a clutch fan stop spinning if it hits water?

Viscous fans will stop if you chuck your hand in their path, so water should stop them too I would imagine...

So would you bet your hand on this? Show me on mine when i rock over this weekend

[christover1]

Fatzook wrote:

christover1 wrote:

Fatzook wrote:

christover1 wrote:

Does a clutch fan stop spinning if it hits water?

Viscous fans will stop if you chuck your hand in their path, so water should stop them too I would imagine...

Thanks, I'll take your word on that,
not brave enuff to test that.
Thats good tho.
One less thing to do during engine instal.

They can sieze though. Not good for the hand then

I keep trying to use the fan to assist in turning over engine by hand.

Old Sierra habits are hard to kick

So mine spins freely by hand,
only assuming its actually spins when it should.

[Fatzook]

JrZook wrote:

Fatzook wrote:

christover1 wrote:

Does a clutch fan stop spinning if it hits water?

Viscous fans will stop if you chuck your hand in their path, so water should stop them too I would imagine...

So would you bet your hand on this? Show me on mine when i rock over this weekend

I've done it once before. And no it was not intentional. Was doing some hardcore leaning on the radiator support and it all got a little too much for me. Lost some skin and blood.

I'm happy to watch you do it though

[neofitou]

Ive tested it.. not intentionally.
I had a sore hand, but I still had all of it so that's okay.

[Built4thrashing]

I found the best thermo to use is one with a square shroud that covers the entire radiator. I used then gave to PJzook a cut down AU thermo. It pulls shit load more air than a 12in aftermarket round fan.

[whincup]

Jazzor wrote:

The buzzer sounds like a good idea!, i have left mine off once or twice by accident :/.

I just cable tied mine to my radiator. But some thermo fans/radiators i've seen some with special cable ties. They have a flat block one one end with some padding under, and on the other end there is another wider block with some padding that cable tied up to pressure. I assume this spreads out the load.

zip-tieing it to the fins like that, is there any risk of wrecking the radiator? i've just bought a new one so not keen on wrecking this one...

and gwagensteve, ideally id just run the stock fan since ive never had any issues with it, up until it ate my radiator. thats the only reason im going thermo...

[Jazzor]

If it was loose i assume it would work its way looser. Should be aight if its snug? .

That's a new to me vit radiator too, so i wouldn't really like it too much if it ripped out either lol. Its probably only been on 5 or so 4wd trips.

Actually I had the same thermo fan on a sierra radiator before for a lot longer and it was fine on that one too.



I think i changed as the one that goes on the jimny engine didn't fit or was in the wrong spot.... and so you can turn it off

[michaelsj70]

I have a aluminum radiator with a made up fan shroud with a 14" electric fan do yous think this will work and it has a thermo switch on the top hose

[SuziBlu]

Gwagensteve wrote:

Shandy wrote:

I'm looking to instal a thermo as well for the same reason, but instead of making an arragement to over ride for water crossings and the like, i figured just put it on the front of the radiator. the blades will pull away form the radiator and you cant leave it off. Its not as eficant and there is probaly a really good reason i haven't seen it done.

A) the loss of efficiency is the reason you haven't seen it done. Pushers are common as "helper" fans for A/C etc, but they aren't suitable as a primary fan.

B) are you sure putting the fan in front of the radiator won't stop the blades hitting the radiator? I think the blades will still be pulled towards the radiator so the risk is the same. I've had a good think about this and I'm pretty sure I am right.

I don't understand the fascination with thermos. Removing a simple, effective device and replacing it with a more complex and less effective device seems silly.

Kind of like running a smaller alternator to make more power or something.

Steve.

PS I have thermos, but It's pretty hard to run a mechanical fan behind the cab. They are also out of the mud.

Steve, as a pull fan, ie in the engine bay, they blade are trying to hit the radiator, as a push, they are pulling/pushing away, surely you can see that, unless of course you have wired them up the wrong way.

I have mine in front, works perfect, hardly ever comes on, only in bog slow mode, or if airing up, then it will come on for maybe 20 seconds at a time.

How is a far better designed fan less effective ?, you keep saying this, never offer any reason why its less effective.

Mine never comes on whilst on the road, so, sort of like not even 1,000,000 of a percent drag, I have it set to come on a tad after the Thermostat opens fully, so as soon as any hot water enters, fan cools it. I did this by trial and error, using an infrared temp gun and watching the water in the radiator move at different speeds as the thermostat opens to full.

Blade design is an art, ever developing, ever changing, ever becoming more efficient.

[MrRocky]

Vit clutch fan is best option

[SuziBlu]

MrRocky wrote:

Vit clutch fan is best option

Why ?

[Gwagensteve]

SuziBlu wrote:

Steve, as a pull fan, ie in the engine bay, they blade are trying to hit the radiator, as a push, they are pulling/pushing away, surely you can see that, unless of course you have wired them up the wrong way.

Yes, you are correct Suziblu, I had it around the wrong way. The blades will be pulled away from the radiator when the fan is used as a pusher.

Quote:

How is a far better designed fan less effective ?, you keep saying this, never offer any reason why its less effective.

Pusher fans are less effective than puller fans. Air is pulled more efficiently though a restriction than pushed, and additionally, a properly installed puller fan (mechanical or electric) will be fully shrouded so the whole radiator surface area is cooled. A pusher fan isn't fully shrouded so it's inherently less effective because bits of the radiator won't experience the higher pressure the pusher fan is exerting.

Quote:

Mine never comes on whilst on the road, so, sort of like not even 1,000,000 of a percent drag, I have it set to come on a tad after the Thermostat opens fully, so as soon as any hot water enters, fan cools it. I did this by trial and error, using an infrared temp gun and watching the water in the radiator move at different speeds as the thermostat opens to full.

What? That strikes me as a fundamental misunderstanding of how a cooling system works, but anyways, more power to you. Engines need to be at temperature to be efficient.

Quote:

Blade design is an art, ever developing, ever changing, ever becoming more efficient.

No, this is completely and utterly wrong. Blade design is a SCIENCE. It's improving, but not at all that great a pace. Aerodynamics is reasonably well understood. Most fan designs are pretty old and much of the tech is about getting them to run quieter. It's easy to make a fan throw heaps of air noisily. people don't want their modern cars to be noisy though.

Once again, there's some truth in what you're saying, but also a lot of projecting your wishes as fact, so, if you were actually serious when you asked why, very carefully read my response to this:

Suziblu wrote:

MrRocky wrote:

Vit clutch fan is best option

Why ?

Because on balance, a Vitara viscous fan is far-and-away the best solution for a Sierra, and mechanical fans are far-and-away the best solution for any offroad vehicle.

1) Electrical load. For a thermo fan to approximate the output of the factory fan, it will consume at least 120% of the crank KW of the mechanical fan. If the claims for how much power is "lost" though the mechanical fans is true, then a comparable electric fan must consume an enormous amount of power when operating - such that very heavy wiring and an excellent alternator would be required just to run the fans. Cooling fan loads of >70A are talked of where there is room for enough/large enough fans.

2) But that's (thankfully) not true. An electric fan in the size that can be fitted to a Sierra radiator, draws a fraction of the air of a Vitara viscous fan. as such, they draw a fraction of the current from the alternator that a mechanical fan draws from the crank.(remember if they didn't then the whole "lost power" argument would be false) Surely that's a good thing? Well, maybe. At low engine speed and light, fluctuating load, a thermo is fine, but under consistent high engine speed and load, they pull less air than a stock mechanical fan, and overheating is common, especially where there's only room for a single, small thermo as in a Sierra radiator.

3) Complexity. Basic engineering practice tells us that the simplest solution is the best. Viscous clutch fans are simple, serviceable, reliable, cheap, and can be locked up in the event of failure. Thermo fans, their associated control and wiring do not match the reliability of a clutch fan. They are also more expensive, (especially if the latest, "most efficient" designs are sought) and all of those parts are vulnerable to dirt and mud ingress. That's why thermo fans are unheard of in heavy equipment for engine cooling. It doesn't make sense when there's a crank spinning away there in the right spot.

4) Power loss. "lost power" is the common myth used to argue for thermo fans. This is undoubtedly true for 100% mechanical fans (with no clutch) which run regardless of engine temperature, however, it's categorically not true for viscous fans. When the engine is below or at temperature, they consume approximately no power - idling freely. Do they consume "no power" - well, of course not, there is a tiny amount of drag, but remember that for a given cooling task, a thermo is already at least 20% less efficient due to rotational force being turned into electrical power and then back into rotational force.

5)but all these manufacturers use thermos! They must be teh bestest! Well, a manufacturer has a whole range of things they are trying to juggle. Noise, emissions, production expediency, cost, engine location, radiator size and location, but mostly emissions. Thermo-management is enormously complex in a modern power train to ensure minimum emissions. That's hardy the case for us and it's not the case for offroad vehicles where it's hard to find a thermo - Defender, Land Cruiser and pretty much every off-highway vehicle uses a viscous mechanical fan. I can speak from experience that in the Defender its enormous, noisy, and almost never runs unless I have the air conditioning on. The defender doesn't have a helper fan for A/C operation, because the Viscous fan is both huge and very sensitive. Yes, I can really feel its operation once it's running, but that's very infrequently. For a thermo to shift that much air it would be very, very costly and power consumptive.

6)But the power! The lost power! Nonsense. if the clutch fan is in, you needed the cooling, so you're thermo would have been in too, consuming less power to do less cooling or more power to do the same cooling. If you're assessing power at WOT you're talking 3000rpm upwards, so that's the RPM a thermo runs at, so you're comparing like for like. At low speed, I used to feel the effect of my thermos kicking in when I was 660cc/manual, so we can talk about "power loss" with thermos too.

In short - thermos can be well engineered, badly engineered, or not engineered at all. Or you can bolt on a viscous clutch fan and not give any of it another thought.

Use a thermo if you have to. Use a viscous clutch fan if you can.

[SuziBlu]

Steve, nice answer.

Reality is, yes fan design is a science unto themselves, it is a vibrant ever changing thing, look at a stock blade, it is seriously the most inefficient design. This is a fact.

Propeller, be it on a plane, boat, or in a fan, is a work of art, science. I do not know if you understand the dynamics of a blade, from your replies, it seems you do not.

Along the full length of the blade, be it near the hub, or at the outer edge, from a 1" blade, to a 15' blade, it will throw the exact same volume, water or air.

The very cheap stock, blades, have nothing like this efficiency, therefore they are not working to to maximum efficiency, modern thermo fans, use a much better deign, meaning, they can pull or push a far greater volume of air, for a far greater reduction in power loss.

This is why all modern cars use thermo fans, better design, less power loss, greater wind flow, even better reliability.

In relation to reliability, only a solid/fixed fan is most reliable, oil/temperature clutch activated or electronic/temperature activated fans have, possibly some small issues.

Most efficient, the latest thermo fans, most reliable, stock fixed to engine rev fans, most inefficient design, power draining, the stock suzuki fan.