Scottay5150

New member here. My wife was insistent on always driving some type of euro car. I balked at her, calling her requests "eurotrash". Now I understand the love of the Audi brand. I have a B7 S4 and she has the Allroad.

I have read many articles on the exploding fan blade problem that exists on these vehicles. Has there been a TSB or recall on the disintegration that happens with these things?

I have not seen a DIY on YT for this surgery to replace the blade. I have little idea on how hard it is going to be for my father in law and I.

I found this: https://www.audiworld.com/forums/aud...laced-2828873/ I don't think it is the exact install, it looks like the real estate is much greater with the link than what I am looking at with the room between the radiator and fan clutch.

How much time can I expect to invest in this job, the DIL is handy this is my first real car fix.

Thanks in advance!

G0to60

Personally I would either just delete the clutch fan (remove fan blades but leave the clutch) or replace it with and electric fan. I wouldn't want to replace that clutch fan with another that may come apart. There is a kit sold by JHM Motorsport that replaces the clutch fan with an electric fan.

Whatever you decide, in order to get the old fan off you will need to put the car in service position (search that phrase and you should find a DIY) which basically means taking off the front bumper, lights, grill, etc.

twentysevenlitres

Just as an FYI, the clutch fan is the main cooling fan. So you will need to replace it with something.
The auxiliary fan is the smaller electric fan.

This is the first I've ever heard about exploding fan blades, so I'm not sure I would even be concerned about it...

Depending on the kit to replace it with an electric fan, its worth noting that the thermoswitch in the radiator activates at a fair bit higher temperature than the thermostat, so it might be worth investigating if a lower temperature switch exists so you don't always feel the need to run the a/c (as that cycles the fan switch more often).
Just my 2c on thermofan conversions...

twentysevenlitres

Not a bad kit at all!
jhmotorsports.com/.../jhm-electric-fan-kit

John535is

I have heard about the 'exploding' fans.
From what I understand, if the fan gets damaged, it becomes unbalanced then can basically get the death wobbles and break apart, sending plastic blades flying around.

I check mine every now and then, if you have an allroad, your head is regularly under the hood, so just spin the fan slowly and make sure it's not cracking up.

The other half of the story is that the fan to fit the allroad clutch is more expensive than the A6. There was a write up on one of these forums that it's cheaper to buy an A6 clutch and A6 fan as the replacements . I believe the A6 part numbers are 078121350A for the clutch and 078121301E for the fan.

PetrolBear

Agree.
I had this issue. It is quite common thing at high performance cars that produce lot of heat. During the years the blades may crack, even on BMW X5, M3, etc...!
So on such cars, one should check the blades at least once, monthly. It takes 15 seconds with a lamp.

I advise strongly not to swap the original design!

Because:
- Such electric fan kits are insufficient low performance (about 400W ? )
- it would not be connected organic way to the heat management system of the engine. Refer: download ssp198 about the biturbo engine.
- There are other chinese manufactured viscous fan swap kits including electric fans on the markets.. but I dont think you would rely your engines health on a single chinese aftermarket relay (uhhh) or fan...

Last but not least - in case you throw out the viscous fan (as mentioned below) you will boil your engine very soon (and turbos as well) I have not heard such thing before....the electric aux fan is designed only for additional support, and for AC, and tranny oil cooling. The viscous fan is the main one.



So
you should buy the original blade fan. NO aftermarket solution, only OEM. There are two designs, basically. One is until cca MY2003 with the 3 bolts (fanblade connected to the clutch) or with latter one with 4 bolts. You can see this only if you removed the clutch. Or eventually with a small mirror (bolts are heading towards the engine front)
The writing is about OK. It is not very easy to remove. As first DIY I would think it over.

Hence

Check the viscous clutch axle as well. It should run precisely. Watch the fan at idling. The blades should run perfectly in line! At the blade ends, about 1-2mm "play" I mean swinging should be seen, as maximum. Otherwise, the worn clutch axle will execute the new fanblade, since at higher rpms (highway) there will be serious twisting forces, combined with the engine heat which will drive to material fatigues and early cracks.

Kneale Brownson

That link in the OP's message is to my writeup of how to replace the original Allroad fan with a viscous clutch and fan blades for an A6 or S4. There's adequate room to work between the fan and the radiator if you remove the boost tube. The A6/S4 blades lack the outer plastic ring of the Allroad, which virtually every one available from Audi will crack and split apart eventually because of the way they're made. Make sure you get a good OEM S4/A6 blade set (not the junk no-name I installed initially) because the cheap POS I used first lost most of its blades in 15-below-zero temperatures. The A6/S4 blades make a bit more noise than the original Allroad design. You do need the A6/S4 viscous clutch because the A6/S4 blades won't go onto the Allroad viscous clutch.

Scottay5150

Everyone thanks for the replies!