electric fan conversion or mod engine fan?

[Mattman]

For the second time now my engine driven fan has smashed my radiator and damaged it.

This time the fan has cut open the radiator and destroyed it.

Truck is a 3.1d bighorn. The fan was recently refilled with viscous fluid and cools very well. The factory shroud is missing.

For those that do a lot of river crossings, will the shroud prevent the fan from kissing the radiator? Or is it time to convert to electric fans?

A set of el-au fans with shroud look like they will fit well......

Matt.

[Weemsy]

Electric on a temp switch, with an 'off' switch for river crossings.

I found I kept forgetting to turn fans on or off without it being temp controlled. Luckily not long enough to damage motor!

[NB42]

The shroud is there to aid the fan in air flow. If it kissed the radiator that badly id be checking all the mounts as something has moved quite significantly to do this.
Imo i'd stay viscous if doing offroading as personally i wouldn't trust an electric fan in the water/muddy conditions especially since when the 3.1s overheat the most times crack the head as well.
My 2.8 mu had a bit of a mark from the fan hitting the rad before i bought it and i found the radiator mounts broken.

[Mattman]

Thanks for the replies guys.

The radiator mounts are fine, all that has happened is that the plastic fan has flexed and kissed the radiator and cut the tubes. I just wondered if the shroud would prevent the fan seeing direct water?

The plan for the electric fans was to have auto/on/off switch. If they aren't running then they should be fine in the water.

Matt

[DMcCready]

One of the reasons the viscous fan has hit the radiator is they were never designed to run in water... What is happening is with water having a greater density than air when the fan hits the water/ mud it tries to act like a boat propeller and pull the motor into the radiator. The flex in the fan is what allows this to happen. You will break off or crack blades and when you look at the radiator the outer part of where the fan has hit will be deeper than towards the center.

I have been on a couple of deep water trips where some guys have loosened or even removed the fanbelts to avoid this happening

A shroud will help alot. Especially if it comes back far enough to cover the fan blades so the fans cant really come into contact with the water.

Electric with a good shroud is usually just as effective to keep a motor cool but you gotta be careful if you run a switch to turn it off for the water crossings... real easy to forget to turn it back on

The electric fan on my buggy has been wired so the truck wont start until the fans are on. Just another safety step to not forget about them

EDIT I type to slow... good to see there wasnt anything come loose that caused it to happen

[Smurf]

Are you sure it is just the blades flexing?
I have no idea how much space there is between your fan and radiator.
But,
I had this issue years ago in a Mitsi, that in rivers with the jarring from bouncing over the rocks that the engine and gearbox rubbers allowed the whole engine to bounce forward and allow the fan to eat the radiator, perhaps a combination of the fan flexing as well but in my vehicle there was no way the fan blades could flex far enough to hit the radiator without the engine moving forward.
I replaced all the rubber engine and gearbox mounts and put in a length of chain off the transfer cross member to the gear box that stopped the engine etc. from moving that far forward.

[ChurchurDan]

Its a shame the bighorn alt is in such an arse of a place. A quick belt release like the old army jeeps had would be the bee's knee's.

[Mattman]

Loosening the belt is not an option.....

I am tempted to go with a set of falcon au fans. They cool a 5L v8 so should do okay for the 3.1TD

I am confident that it was the water as only the tip of the blades struck the radiator. If the rad or motor was moving there would be a lot more damage.

Thanks for the replies guys.

Cheers

[Ralfie]

How deep was the water ............
and how fast did you hit it?

You don't happen to have a body lift by any chance?
Therefore the reason for no shroud ...........??

[Weemsy]

If you can, try and find the electric fan assembly from a 2006? Ish onwards Audi A6.
Sounds a bit extreme, but! They are a nice, 2 fan setup. They have a little control unit with them that varies the speed of the fan. They are 2 stage so only one comes on until about 95 degrees then the other kicks in and they are very very good and very waterproof.

I had them on my hilux and they were the mutts nuts.
They pull so much air that if your engine goes bang you could blow your way home

[lax2wlg]

Matt I've been racking my brains and I think it was the first mud hole at the end of the airstrip, early in the day.

I heard a crackling/semi carnage noise as the Isuzu entered the water, at the time I thought it was just branches or rocks etc.

How deep was the water ............
and how fast did you hit it?

Top of the wheels deep & sloppy.
He didnt hit it fast, just enough momentum for the Isuzu to get sufficient wheelspin to walk through it.
I went too slow and had to reverse to first my way through

[churchill]

Is this a common problem? All the original viscous fan setups I've seen basically disconnect when the radiator is not needing cooling. I can turn them by hand so I thought when the cool water hits the hub centre they would just free spin. Maybe the fluid in the centre is the wrong weight/quantity?

[Mattman]

I had just refilled my viscous fan and its very tight now hence the carnage on the radiator.

No shroud because the original fan let go and destroyed it.

There is a nice 40mm all alloy radiator on trademe for $320. I am going to get that and tap the top tank for a two stage thermo switch and run the falcon fans.

The stock rad is 32mm. The alloy rad will allow me to tig on brackets to mount the fan assembly as well.

Pics to come!

[Mattman]

Matt I've been racking my brains and I think it was the first mud hole at the end of the airstrip, early in the day.

I heard a crackling/semi carnage noise as the Isuzu entered the water, at the time I thought it was just branches or rocks etc.

How deep was the water ............
and how fast did you hit it?

Top of the wheels deep & sloppy.
He didnt hit it fast, just enough momentum for the Isuzu to get sufficient wheelspin to walk through it.
I went too slow and had to reverse to first my way through

I think you are right Josh. That sealant I used was amazing!

[meatc]

What about getting a 6mm alloy rod made into a circle a bit smaller than the od of the fan and get it tacked to the ally radiator. If the blade flexs the rod will prevent damage

[Mattman]

What about getting a 6mm alloy rod made into a circle a bit smaller than the od of the fan and get it tacked to the ally radiator. If the blade flexs the rod will prevent damage

That's not a bad idea actually. Two blades snapped off and caused some damage but those rings would stop most of it.

[meatc]

What about getting a 6mm alloy rod made into a circle a bit smaller than the od of the fan and get it tacked to the ally radiator. If the blade flexs the rod will prevent damage

That's not a bad idea actually. Two blades snapped off and caused some damage but those rings would stop most of it.

Blades snap due to excess flex, the rod will reduce the distance it can bend, could mount it off the radiator and closer to the fan to stop even more flex

[ChurchurDan]

If you going to do that just put some steel mesh between the fan and radiator.

[zukmeista]

If you going to do that just put some steel mesh between the fan and radiator.

This is what I was thinking but the fan may catch and get damaged, the round rod should allow the fan to slide around it without too much damage to the fan, may wear a groove over time though.

[derk]

just out of interest what is the static clearance between the fan blades and the radiator and have you had a good look at your flogged out 20 year old rubber engine and trans mounts to see what sort of engine movement you've got bareing in mind the drive train will move shitloads more than what you can flex it with a big bar in there to see what sort of movement you've got


if you want to go into sloppy muddy holes electric is the only way to go a mechanical fan with pick all the shit up and throw it all around the inside of the rad and block it, the only problem with electric is you always remember to turn them off for a big hole but its hard to remember to turn them back on so an audible temp alarm is a wise move, and don't forget to make sure you can slide a blind down in front of the radiator when you mount the new one in there

[Mattman]

Anyone have pics of a radiator blind?

[jonossiksilvia]

Anyone have pics of a radiator blind?

will have a pic in couple weeks once i make mine. i making a mesh one though. materials yet to be determined

[derk]

Anyone have pics of a radiator blind?

[Crash bandicoot]

electric fans mounted in front blowing air through as apposed to sucking it will force the fan blades away from the radiator when immersed in water...handy hint

[zukmeista]

Anyone have pics of a radiator blind?

[img]

At first I was like WTF Then I realised you were suggesting using a real estate sign, I have seen this done before just have to remember to remove it to avoid overheating, bit like remembering to turn a leccy fan back on I spose.

electric fans mounted in front blowing air through as apposed to sucking it will force the fan blades away from the radiator when immersed in water...handy hint

Yes but they are less effective at cooling when pushing instead of pulling. Not that you want an electric running in water anyway, will probably blow the fuse.