Idling at 1,000rpm and fans running - please help!

[ducman77]

Hi guys,

So my car has been Idling at 1000 rpm and the fans are running even when the engine is cold.

I have searched on here and Google etc. VCDS scan shows coolant temperature sensors working okay. And an output test of the fans sees them functioning normally. No faults on the VCDS in general.

Alternator is only making 13.4 to 13.5 V at idle.

I know the fan control module in the big fan can go faulty. But the output test for the fans is normal?

Has anyone got any thoughts what could be going on here? I am at a bit of a loss! Thanks in advance!
Dave

[amanda]

Voltage on alt seems iffy.......are you sure this isn't the cause of the prob?

Spiking can cause all sorts of unrelated probs

[ducman77]

Cheers Amanda!

I'm a bit suspicious of the alternator alright. I have a virtually brand new decent 76AH battery in the car and I've already had a "low battery voltage" message on the VCDS.

I put the battery on overnight charge last night and so far I've not had a recurrence of the high idle and fan issue yet today (only done one short drive mind you)

I'll keep an eye on battery and alternator performance over the next few days and see if the problem recurs.

Thanks for the reply
Regards,
Dave 

[pudding]

The low voltage could be due to the fact the fans are running full blast?  They pull a lot of current!

Same thing happened on my MK4 R32.  The cause was a duff fan controller.  It was bolted to the nearside wing under the battery tray.  Do MK5s have fan controller boxes?

If they do, that's where I would start investigating!

The fan controller runs the after run coolant circulation pump as well as the fans (on low speed) when you switch the engine off.  When it fails, the most common symptom is what you've got there buddy.

[ducman77]

Thanks for the reply pudding. Very much appreciated

I've been reading a bit about the dodgy fad controllers alright. Seems they are still a very common fault on the mark five as well as the mark four

On the mark 5 the large fan has the controller built into it. Unfortunately, the price for a new fan from Volkswagen here in Ireland is €350!!

I don't fancy fitting a spurious one. Anybody got any idea of how much a new fan is from a UK VW supplier?

[ducman77]

Did some more research on the alternator and battery over the weekend;
Alternator seems ok. Gives 14.4V when required.
And battery is holding 12.6V when left for 24+ hrs.

Fans still coming on randomly and not when you would expect. I.e. Neither the engine nor the weather are hot. Not in stop start traffic etc.

So, as pudding said, I think a dodgy fan control relay is the culprit. Anyone know a good place to source the fan? Irish main dealer prices are too high at €350 for just the main fan unit??

[notolly]

I might have the same problem here noticed fan randomly on too. Il see what i can find for a replacement fan controller

Sent from my SM-G935F using Tapatalk

[Markis236]

The controller is built in the fan of this is faulty it's a new fan pack ! Easy job though just undo the throttle pipe and 4 torx and a master plug and that it off ! Just shop around on eBay I got a second hand one for £50 delivered

[ducman77]

I might have the same problem here noticed fan randomly on too. Il see what i can find for a replacement fan controller

Sent from my SM-G935F using Tapatalk

Cheers for the reply. Think the only proper fix is a whole new fan cos the controller is built into it

The controller is built in the fan of this is faulty it's a new fan pack ! Easy job though just undo the throttle pipe and 4 torx and a master plug and that it off ! Just shop around on eBay I got a second hand one for £50 delivered

Cheers for that buddy. The second hand item was ok? Might go down this route too. But I'd be a bit nervous that the second hand one might be a dud too

[Markis236]

Ye I bught one and it was damaged so sent it back but as long as you email them asking if it is fully work you can just sent it back  for cheaper then going to TPS for one

[exodus_ste]

I got a brand new fan pack from euro car parts, wasnt that bad price i dont think and im pretty confident it is the problem im having as i have exhausted all other options.

http://www.eurocarparts.com/ecp/c/Volkswagen_Golf_2.0_2007/p/car-parts/cooling/car-cooling-parts-and-car-heating/car-fans/?213440290&1&2cf4259c92b8dd7146756e9974f628b6d7b9c6a0&000128

My issue was fans not coming on when engine gets hot, yet output test in VCDS showed the fans working fine.

[ducman77]

Ye I bught one and it was damaged so sent it back but as long as you email them asking if it is fully work you can just sent it back  for cheaper then going to TPS for one

Cool. Thanks a million for that.

I got a brand new fan pack from euro car parts, wasnt that bad price i dont think and im pretty confident it is the problem im having as i have exhausted all other options.

http://www.eurocarparts.com/ecp/c/Volkswagen_Golf_2.0_2007/p/car-parts/cooling/car-cooling-parts-and-car-heating/car-fans/?213440290&1&2cf4259c92b8dd7146756e9974f628b6d7b9c6a0&000128

My issue was fans not coming on when engine gets hot, yet output test in VCDS showed the fans working fine.

That's brilliant mate. Thanks a million for that link. That's a brilliant price for both fans and the shroud. Top job 
Thanks for posting it