Small engine fan

[NotoriousARG]

I am running a 2006 Octavia VRS and recently I've noticed the engine fan is really noisy. On closer inspection even when the air conditioning is running only the larger of the two fans will spin. The smaller fan wont start at all. I've had my mate plug a diagnostic computer into the car and it's not showing any errors. I've also replaced the fan fuse just in case but it's still doing the same. Do I need a whole new fan set?

[alw70]

To check that the small fan really has failed you need to run the output test for the fan controller using VCDS. If the fan doesn't run during the test, it's knackered.

You can replace the small fan on its own, when mine failed I got a second hand one from eBay and it was very straightforward to change. Jack the front of the car up, undertray off. Unplug the main plug to the fan unit from underneath the car, undo the two screws holding the fans under the car. Undo the last two screws at the top of the fans and pull the fans out upwards. Change the fan and then refit!

[SuperbTWM]

When the small fan is knackered it runs the larger fan at high speed when the air con is on. Had to change mine on my Golf mk5, cost an arm and a leg for just a fan.

Edited 12 July, 2016 by SuperbTWM

[Extreme3d]

Had this on mine recently, always the larger fan running, and never the smaller one. Turned out to be one of the brushes stuck in its holder.

As previously mentioned, under tray off, air intake off, disconnect l/h intercooler hose for access, disconnect electrical connector, remove four bolts securing fan and withdraw from the top.

Remove the fan that is bolted to the frame, disconnect electrical connector.

You now have to remove the rear casing using a smal dremel drill with cutting disc, cutting the tangs out that hold the cover in place, once released tap the back off and you will have access to the brushes and the commutator.

You will see immediately that one or both of the brushes are stuck in their holders. Remove them, clean up the holders and surrounding area's. Refit the brushes and springs. The next trick is to reassemble the rear casing (cover/brushgear) back onto the commutator. (Its not to bad).

Now to secure the rear case having cut off the tangs, I cleaned the area and used epoxy (JB Weld) at various locations around the cover. Waiting for it to dry completely. Oh I checked with a mutimeter the resistance across the motor connector to ensure the brushes were seated properly.

Now put everything back together in reverse order

Shouldnt take any longer than 3 hours and probably save yourself at least a £100.

 

Now I have a much quiter car and both fans run when necessary at a slower speed when the a/c is on, sitting at idle.

 

Have fun!

 

Edit: I had no vcds errors and could not find how to turn the fans on using vcds.

Edited 12 July, 2016 by Extreme3d

[Extreme3d]

In addition, don't forget to disconnect the cars battery.

 

The larger fan controls the smaller fan, when it senses the small fan not operating (failed) the large one works at full speed (as SuperbTWM has said).

 

And here is a link I have found to assist, http://www.myturbodiesel.com/wiki/radiator-ac-fan-motor-repair-on-mk5-vw-jetta-golf/

Edited 13 July, 2016 by Extreme3d