Another Cooling fans topic... VR6

[swindon-corrado 0]

Have we got a definitive guide on resolving this VR6 cooling fans thing yet ?

 

My fans have decided not to work at all. The horn works meaning the after run fuse is ok.

 

I have replaced the Aux Water Pump with a new VW one last year.

 

The temp gauge is working ok.

 

Tell me if wrong but I will bypass the sensors firstly and bridge the connections in both the Yellow (4 pin) and then Black (2 pin) connectors to make sure the actual fans work.

 

After that where should I be looking ? At the control unit ? Or under the dash for relays ??

 

And rather than a hit a miss affair of replacing all sorts to cure is there not an effective way of testing the control box or associated relays ?

 

Cheers ..

[ReekieVR 0]

Have we got a definitive guide on resolving this VR6 cooling fans thing yet ?

 

Nope. I was seriously thinking of trying to have a look inside the control box itself. It cant be that complicated in there. Anyone had a looksee ?

[swindon-corrado 0]

Definately need a knowledge base article on this..

[Jim 2]

Feel free to write one and submit it for addition to the Wiki! :)

[ReekieVR 0]

Well, i was hopeing that when DelMonty was at Stealth he could get an idea of the troubleshooting Vince would do ( see 'Cooling fan after run strangeness...' thread ). This info, together with info pulled from all the threads here, would be all that was needed to create a Wiki thoubleshooting guide.

 

I dont mind doing it - with a bit of peer review to ensure it makes sense before submitting!

 

No news from Del yet though :( ( he is waiting on an MOT tho )

[Kevin Bacon 5]

Use the search, I've already gone through it 100 billion times.....

 

1) Check rad switch - Pull connector off, bridge solid red wire to common ground for speed 1, bridge red/black wire to common ground (3rd wire) for speed 2. Speed 3 is in the black sender.

 

Ignition needs to be on to test Speeds 2 and 3. 1 is direct to battery.

 

Keep well away from the fans when testing 3.... you'll see what I mean :-)

 

Speed 1 - 90-95 degrees, Speed 2 - 100-105 degrees, Speed 3 - 120 degrees

 

If speeds 1 and 2 don't work, but 3 does, replace the sender in the radiator.

 

If none of the speeds work, suspect the controller module assuming the fuses are OK, and that'll be £100 from the dealer, plus the shat. They very rarely go to be fair.

 

You'd do well to dump the heavy weight, heavy current drawing OE fans and fit some more efficient, quieter, cheaper slimline SPAL fans and just run them off speed 1.

[ReekieVR 0]

I have done the search as many times as you have gone through it Kev and still havnt found a troubleshoot for hot start problems. Perhaps i am looking for the answer to a different question than swindon-corrado !

 

What about the whole run-on circuit?, relay checks ( which ones are they? How do you test a relay? ) Neither aux water or fuel pump not running on - where do yo start with testing these.

 

Thanks for posting the fan troubleshoot though. Can you submitt it to the Wiki? Then you'd stop having to go through it ! ;)

[Kevin Bacon 5]

Everything for the fans and after run is controlled, fused and relayed in that big old box by the header tank ;-)

 

Even when cold, simply turning the ignition on/off should kick start the after-run timer (10 minutes) and you should hear the Aux pump. If not, suspect the box.

[ReekieVR 0]

Ahh - thanks.

If the 5 amp is for the aux water pump, is the 20 amp for the fuel, and the 50 amp for the fans then ?

 

Seems i need a 2nd hand control box then ? Mine does not do the 10 min run. :(

[fla 9]

Use the search, I've already gone through it 100 billion times.....

You'd do well to dump the heavy weight, heavy current drawing OE fans and fit some more efficient, quieter, cheaper slimline SPAL fans and just run them off speed 1.

 

I've got a 11" Spal fan to install. It pulls about 1800m3/hr of air, which i presume is going to be more than teh twin fan setup as standard. Does anyone have experience of an alternative or would the two fans also need to be replaced with a double fan setup?

[Kevin Bacon 5]

ReekieVR, in the box, you should have a few fuses. The big mofo one is defo for Speed 3. The smaller blades are for the other speeds and prob the aux pump, can't remember!

 

fla, I've got just the one 11" spal on mine (at the alternator end) and the coolant never goes over 100 on the dash guage. It's certainly more effective than the OE speed 1 and 2, but not speed 3. You'd need 2 spals to acheive that.....but speed 3 should never come on anyway, if it does you have issues!

[fla 9]

kevHaywire, have you wired it in to replace the existing fans? If so, I presume it operates according to the water temp readings? In that case, does that mean it will never run with 12V as per a direct link on speed 3?

[Dutch24V 0]

Aux. water pump also runs of the same fuse/circuit as the internal ventilation motor btw. Think it uses this circuit for the after run cycle.

 

It has two feeds anyhow, one via the fuse in the controller, and one from the main fuse board via said fuse/circuit.

 

I replaced my ventilation fan motor and controller before finding out the aux. water pump uses the same circuit. I replaced that and the fuse stopped blowing.

 

Dutch

[Kevin Bacon 5]

fla, yep, it's just hooked up to speed 1 on the main fan plug. I can't see the need for 3 speeds. It's a bit overkill imo. The Spal is so quiet and efficient you just don't need that great big, heavy, expensive VW assembly.

[ReekieVR 0]

Ok - just did some testing and speed 2 doesnt work. 1 ( with ign off ) and 3 ( ign on ) work fine. Checked the fuses. All ok.

 

Tesed the temp senders a bit too. When cold the black is open, Blue is closed. Will get to temp in a min and recheck. Dont know what this weill tell me !

 

Before starting engine - obviously had to turn ign on to test fan speed two and three. The Aux water pump comes on but goes off again when the ign is switched off.

[ReekieVR 0]

Mmmm, more interesting things:

 

From cold :

 

fans 1st come on @ 85d for 15 seconds. Temp keeps rising till about 92 and no further with multiple 15 second ( all speed 1 ) bursts.

 

Waited till fans were on and swithced engine off:

Fans ran for 20 secs. No aux water pump.

 

Disconnected rad temp switch and ran engine ( to see if speed 3 would come on ): No fans at all. Switched ign off @ 100d - fans come on with aux water for 5 mins. Ign on : fans switch off again.

 

Engine on again:

Water / oil temp rose to 112 speed 3 came on for 10 secs together with aux water pump. Reconnected rad temp: again fans only on when ign of.

 

So some questions and thoughts:

Why would the fans go off when i switch the ign on?

 

Why does the run-on circuit seem to run fine with the rad temp disconnected?

 

I think i should defo replace the rad temp sender.

 

What happened to speed 2 ?

 

Didnt manage to test any fuel pump operation but tried to listen and couldnt hear anything.

 

Any thoughts guys ? Could there be more than 1 problem here? ie fan control box speed 2 circuit is dead, rad temp sender is dodgy plus fuel pump wont run on.

 

Sorry for hijacking your thread swindon-corrado - but our problems sound similar !

[mattkh 0]

Hi

The run-on circuit bypasses the rad switch.

[fla 9]

fla, yep, it's just hooked up to speed 1 on the main fan plug. I can't see the need for 3 speeds. It's a bit overkill imo. The Spal is so quiet and efficient you just don't need that great big, heavy, expensive VW assembly.

 

OK good stuff Kev. I'm going to do the same on mine, although i might just link it up the same as the old fans and get rid of them. Do you think the airco would affect the cooling performance of the fan much?

[aki 0]

Have we got a definitive guide on resolving this VR6 cooling fans thing yet ?

 

Nope. I was seriously thinking of trying to have a look inside the control box itself. It cant be that complicated in there. Anyone had a looksee ?

 

 

nope its not too tricky inside the control module just 3 relays from what i remember and some electrickery gubbins, i had all sorts of probs with my fans untill i took the module off the car and shook it..... it rattled! cracked it open and resoldered the bits that had dropped out of the circuit board and its been fine for the last 12months or so!!

[swindon-corrado 0]

Have bought a new rad switch so will try that today...

[fla 9]

Is there any way to link the SPAL fan to speeds one AND two, rather than just speed 1?

[swindon-corrado 0]

Blimey, I posted this 8 years ago.. Don't have the car anymore, engine blew about 7 years ago. How time fly's !

[Stonejag 10]

Is there any way to link the SPAL fan to speeds one AND two, rather than just speed 1?

Hey Hasan,

 

Yep, just join the two outputs from the thermal switch in the radiator. Then they're just in parallel so either switch closing will trigger the fan relay. Although my Spal setup works it can still overheat when stuck in traffic for a long while - the coolant temp stops rising at 110 but the oil temp keeps going. Just checking I've not hooked it to speed 2 by mistake, but if I haven't then I'll most likely swap the switch for a single-stage one at a lower temperature - the fitting is industry standard, you just need any thermoswitch with an M22 thread.

 

Will be very glad when I've got shot of the factory wiring too, it gives me the fear! ;)

 

Stone

[Kevin Bacon 5]

You'd have more fear in a MK4 / MK5 as the bloody fans can catch fire in those!!

[MarkFoster 0]

You'd have more fear in a MK4 / MK5 as the bloody fans can catch fire in those!!

 

Ha! If only everything in life was as reliable as a Volkswagen, eh?!