Radiator fans running high

[shail]

I've noticed the last week or so that my radiator fans run on high even before the car is up to temp.  This happens with AC on or off.  What could this issue be?  They are really loud, and the only other time I've heard them this fast /loud is after a long run in the height of summer.

[FatWelshBoy]

Fan control module is what I've been told, it fails safe so will run the big fan. My car runs the big fan at odd times and that's what the previous owner had it diagnosed as, I haven't fixed it yet as it's rare that it does it.

[shail]

Thanks for that.  I'll need to investigate that.  Checked a couple of times and one time both fans were running, second time it was only the big fan at top speed.

Plugged in a scanner and the coolant temp coming back seems correct, which I guess rules out the temp sensor.

[pudding]

Yeah if the big fan is running hard on it's own, it usually means the little one is having a hard time. IIRC, the fan controller is built into one of the fans (possibly the bigger one), so if it sees the little one isn't contributing, it over compensates. Or if the controller is in the little fan, it'll run the big one as a failsafe. I can't remember 

[shail]

Yeah if the big fan is running hard on it's own, it usually means the little one is having a hard time. IIRC, the fan controller is built into one of the fans (possibly the bigger one), so if it sees the little one isn't contributing, it over compensates. Or if the controller is in the little fan, it'll run the big one as a failsafe. I can't remember 

I ended up changing both fans yesterday, as it was easier to replace both than figure out what the hell was going on.  Cost about £80 from Carparts4less so not bad at all.  Seem to be working well, but the big one has an everso slight wobble to it, but guess thats what you get if not going OE!

[holepunch]

My 06 GTI has also developed this fault recently.

Having owned the car for 15+ years I’m keen to keep it OEM however I’m struggling to find a online retailer to supply/deliver  the genuine VW fan assembly.

Can anyone recommend site/supplier.

I might change my mind on this approach when I see the price. 

[shail]

My 06 GTI has also developed this fault recently.

Having owned the car for 15+ years I’m keen to keep it OEM however I’m struggling to find a online retailer to supply/deliver  the genuine VW fan assembly.

Can anyone recommend site/supplier.

I might change my mind on this approach when I see the price.  :grin:ei

If you do change DIY, be prepared for bolts snapping holding the shroud in place.  Might be worth spraying some penetrant on bolts for a few days before hand.

I didn't even bother calling VW as I assume we're talking a few hundred quid!

[pudding]

Yeah if the big fan is running hard on it's own, it usually means the little one is having a hard time. IIRC, the fan controller is built into one of the fans (possibly the bigger one), so if it sees the little one isn't contributing, it over compensates. Or if the controller is in the little fan, it'll run the big one as a failsafe. I can't remember 

I ended up changing both fans yesterday, as it was easier to replace both than figure out what the hell was going on.  Cost about £80 from Carparts4less so not bad at all.  Seem to be working well, but the big one has an everso slight wobble to it, but guess thats what you get if not going OE!

Lol, what brand did you go with? I think Valeo might be the OEM maker?

[shail]

@Pudding the brand was Starline.  Quality looked fine until I saw wobble, by which point it's all installed and ive already sheared a bolt............let's just shut the bonnet and walk away.....

[pudding]

@Pudding the brand was Starline.  Quality looked fine until I saw wobble, by which point it's all installed and ive already sheared a bolt............let's just shut the bonnet and walk away.....

Yeah agreed. Some fannage is better than no fannage    Forget about it until they need doing again. Just keep an eye on the wobbling in case the fan blades part company with the housing 

If you don't mind waiting on parts for a week, AutoDoc are good. I thought they were annoying and rubbish at first, but I've used them a few times now and they've come good. Just add stuff to your basket and they start throwing 40% discount codes at you after a day or two, which really brings the price right down.

[shail]

@Pudding I did look at autodoc, but like you had reservations.  Good to have positive feedback on them though as the price was really good.