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Author Topic: Cooling Issues (fanpack/radiator)  (Read 245 times)

Offline golfglos

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Cooling Issues (fanpack/radiator)
« on: June 23, 2022, 08:20:33 pm »
Hi all,

I have a mk5 golf GTI stage2+ and noticed after a spirited drive and standing in traffic, or idling back on my drive the temperature has for the 1st time ever started to creep over 90c on the dial. Looking via obd I have confirmed it says around the same temperature for coolant. When it gets to around 116c or so I'd expect the fans to turn on.. but they don't. Before they would come on with the temp on the dashboard staying at a steady 90c as I'd sit on the drive waiting for them to stop spinning before turning the car off.

Stuff done so far

- Checked and swapped fuse F38
- Replaced the fanpack (twice)
- Fans spin on fanpack when connected directly to 12v

The car doesn't have AC, so I don't think the small fan turning on via pressing the AC cabin button will work.
It wasn't VCDS but sending Engine output test the fans don't spin
Coolant level seems fine, pipes to the res and to/from the radiator appear to be hot

Any ideas?

Thanks in advance

Offline LC5F

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Re: Cooling Issues (fanpack/radiator)
« Reply #1 on: June 23, 2022, 10:21:50 pm »
coolant sensors? both of them.

Offline Pudding

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Re: Cooling Issues (fanpack/radiator)
« Reply #2 on: June 24, 2022, 10:20:13 am »
90 on the dash could be anywhere between 80 - 110 degrees.  They've engineered it to stay in the middle like that, because.....Coolant temp for dummies.  It keeps paranoid people out of the dealers.

Where did you apply 12V directly to the fans? At the main connector on the fan casing?

Did you check the big chunky fuses in the engine bay fuse/relay box? 


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Offline golfglos

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Re: Cooling Issues (fanpack/radiator)
« Reply #3 on: June 24, 2022, 11:43:25 am »
Hey thanks both for the replies

Yeah I understand the dial itself, so I have been checking with an OBD scanner as my first thoughts were the main thermostat was playing up again. still 'runaway' coolant temp shown there.

Yes, 12v directly to the fanpack and fuses/relays checked but I will do so again, I think it was fuse f38 I swapped/checked.

From other reading the next best thing would be the coolant sensor - I think there are two.. going to swap the easier one first.

Thanks for your help

Offline Pudding

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Re: Cooling Issues (fanpack/radiator)
« Reply #4 on: June 24, 2022, 12:30:55 pm »
The scan tool output test bypasses all external controls, and the fact that didn't work points to a problem elsewhere.  Wouldn't hurt to replace the sensors anyway if you think they're misreading/not functioning.

Have you scanned the HVAC controller as that is also tied into the fan control?  You say it doesn't have AC....as in you've removed it, or it was never fitted at the factory?


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Offline exodus_ste

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Re: Cooling Issues (fanpack/radiator)
« Reply #5 on: August 05, 2022, 10:29:28 am »
I've had almost exactly the same issue for a couple of years now! So frustrating. I've also changed the fan pack, both sensors, all fuses are intact but i can get the fans to run full whack during output tests in VCDS.

My AC is not functioning at the mo, think there might be a leak in the system somewhere. Had it re-gassed at AKS a couple of years back and it was icey cold for 3/4 months. For a week or two after having the re-gas my cooling fans worked but not every time it got hot  :thinking:

Genuinely given up with it, just suffer with running the climate at full hot when ever stood in traffic for a period.

Toyed with just fitting a switch under the dash to turn the fans on.

Offline golfglos

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Re: Cooling Issues (fanpack/radiator)
« Reply #6 on: August 05, 2022, 11:10:14 am »
I got this fixed. On the fuse box there are the in-line fuses. 3rd one in is the 50 for the rad control. Testing that there wasn't any voltage. Swapped it out and the fans are now working as they should. HTH!

Offline GVK

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Re: Cooling Issues (fanpack/radiator)
« Reply #7 on: August 05, 2022, 01:10:28 pm »
Thanks for updating the thread with your fix!   :happy2:
Scirocco TDI GT---- VAG scans in South Lincs/Cambs/West Norfolk.

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