The definitive VR6 cooling guide

[fendervg 29]

If you take look around there should be adapters with a longer bolt that allow you to keep the heat exchanger - most just get rid of it. I'd keep both if I were fitting an oil cooler, as part of it's function is to actually help heat up the oil from a cold start and get it to the correct operating temperature, and then to regulate the temperature once it is hot. That's why the correct German description always translates to "heat exchanger" as opposed to "oil cooler".

 

I've also seen oil cooler take off sandwich plates fitted to the oil filter housing, which is a different option.

[Pjkarras 10]

Don’t know if this is the right thread but let’s give it a try.

I am at my wits end with my cooling system

 

I just had my radiator replaced and my shop advised I replace the thermostat fan switch. When I got my vehicle home I noticed the fans not coming on when the motor is hot.

 

So this is the course of action I have taken to try to resolve the issue:

1-replaced the thermo fan switch - no luck

2-jumped the cable at the fan switch and the fans kick on -good and bad

3-replaced the fan control module because I noticed the 5 amp fuse was blowing- no luck- fans don’t come on and new module blows the 5 amp fuse as well

4-replaced the thermo fan switch again thinking I might have a dud- no luck

5- replaced the three thermo sensors on the thermostat housing - no luck

6- tried jumping the yellow sensor wires to see if I can get the after run fan to kick on- no luck

7- checked the wires I can see and don’t see anything wrong.

 

I am out of ideas. One thing I know for sure with everything I have done my fan control module still blows 5 amp fuses.

 

I can get the fans to run on low speed when I turn on the ac. So I can get the temperature to sort of regulate but I can’t run the car like this.

 

Any recommendations I can try would be appreciated.

[Will.I.Dub 11]

Guessing but it sounds like a short somewhere? Have you tested the circuits with a multimeter?

[Pjkarras 10]

I haven’t, what should I check specifically and what am I looking for on the multimeter

[Cressa 43]

Have a good read of this thread, lots of useful ideas. When my 5A fuse was blowing, the cause of this was my aux. Water pump at the right hand side of the engine.

Try unplugging this and see if the fault clears/ new fuse doesn't blow. These pumps don't last forever and can block with debris and failing main water pump plastic blade parts!! If the pump is in a short circuit condition whilst connected it will keep blowing the fuse.

Worth a try,

Good luck

[Cressa 43]

I haven’t, what should I check specifically and what am I looking for on the multimeter

AUX WATER PUMP

Set it to test for 12v DC. Put it across the two pins and with ignition on, you should get 12v if all is working fine,

Hey presto

[Pjkarras 10]

Thanks guys, that was the problem. New aux water pump on the way from amazon.

[tony_ack 0]

Stage 2 is coming on as soon as I switch on the ignition, and staying on constantly. When I switch off the ignition, the fans run on for 10 minutes. It's been off the road for 2 years, fans were working okay when I ran it on the drive and the problem has started now I'm driving it.

 

So far I've:

Checked the fuses on the fan controller

Unplugged the temp senders on both the rad and the crack pipe.

If I unplug just the rad sender, the fans still come on with the ignition, and run on with the ignition off

If I unplug just the yellow sender, the fans still come on with the ignition, but switch off when the ignition is off

If I unplug both the rad sender and yellow sender, they don't come on with the ignition.

 

So, it seems it's not caused by the senders themselves. Any ideas? It's a late VR with late fan controller

[1xshaunx1 27]

1st I’d try plugging in a different sender to the yellow plug. You’ll see if there is any difference without fitting it to the thermostat housing. If it sorts it out then fit it.

My tupence

[Keyo 47]

Stage 2 is coming on as soon as I switch on the ignition, and staying on constantly. When I switch off the ignition, the fans run on for 10 minutes. It's been off the road for 2 years, fans were working okay when I ran it on the drive and the problem has started now I'm driving it.

 

So far I've:

Checked the fuses on the fan controller

Unplugged the temp senders on both the rad and the crack pipe.

If I unplug just the rad sender, the fans still come on with the ignition, and run on with the ignition off

If I unplug just the yellow sender, the fans still come on with the ignition, but switch off when the ignition is off

If I unplug both the rad sender and yellow sender, they don't come on with the ignition.

 

So, it seems it's not caused by the senders themselves. Any ideas? It's a late VR with late fan controller

 

I'm not sure if this part will resolve your issue, however the fan controller is now obsolete.

 

Part number 357 919 506 for late VR6 I have used one £20.00 includes postage.

 

Cheers.

Edited October 6, 2019 by Keyo

[tony_ack 0]

Thanks, I've got a yellow sender on order now, so will give it a try. Kieren - I'd be interested in the fan controller, there may be a couple more things I need, so I'll let you know.

 

Not sure if it is just a coincidence, but the horn and o/'s rear tail light stopped working at the same time the fans started playing up. I've not looked at the horn yet, but the tail light issue is definitely not the bulb or the fuse..

[Keyo 47]

Thanks, I've got a yellow sender on order now, so will give it a try. Kieren - I'd be interested in the fan controller, there may be a couple more things I need, so I'll let you know.

 

Not sure if it is just a coincidence, but the horn and o/'s rear tail light stopped working at the same time the fans started playing up. I've not looked at the horn yet, but the tail light issue is definitely not the bulb or the fuse..

 

Has your car been outside in the rain the last couple of days . maybe the damp has got on a contact or something.

[fendervg 29]

Well, had a scare last night as the coolant temp just seemed to be rising inexorably and no signs of the fans coming on while sitting in traffic on the commute home - another typical Corrado **** in your pants moment!

 

Checked it out this morning and also noticed horn and aux water pump were not working - pulled fuse 13 (10A) and this was blowm, both working again afterwards. Also checked fuse 19, this was fine. Some testing and a trial run and all seemed ok and fans came on at stage 1 as expected around 90 degrees. Didn't get to check stage 2 or 3, in fact I haven't heard the after run fan for a while, so maybe this is also on fuse 13?

 

When I get more time I'll run though the full tests, bridging the connections to run the fan etc.

 

Are there any other fuses on the fan controller unit apart from the mother of all fuses which is basically a big metal bar? I seem to recall seeing some pictures with 2 smaller blade fuses as well?

[tony_ack 0]

The late vr fan controller has two blade fuses on top.

 

It's also powered by fuse 6 I found out...!

 

Not sure about the early ones

[fendervg 29]

The late vr fan controller has two blade fuses on top.

 

It's also powered by fuse 6 I found out...!

 

Not sure about the early ones

 

Thanks Tony - I'll take a look later and check to see if I can find any more on it - it's kind of covered by the bracket that holds it, so will need to drop it.

 

EDIT: on second thoughts, I have the early controller with just the single large fuse, so will need to keep looking. Are the late type ones interchangeable with the early ones by any chance?

Edited October 24, 2019 by fendervg

[1xshaunx1 27]

Have you fixed yours then Tony, if so what was it

[Keyo 47]

Thanks Tony - I'll take a look later and check to see if I can find any more on it - it's kind of covered by the bracket that holds it, so will need to drop it.

 

EDIT: on second thoughts, I have the early controller with just the single large fuse, so will need to keep looking. Are the late type ones interchangeable with the early ones by any chance?

 

Im sure I read somewhere that early models had a 2 stage fan and late 3 stage , could of imagined it though. Would this be the reason they changed over fan controller, I have no idea to be honest but keep us updated on your progress .

 

Cheers.

Edited October 24, 2019 by Keyo

[Keyo 47]

How many sensors do you have in your thermostat Fen ?

[fendervg 29]

How many sensors do you have in your thermostat Fen ?

 

There's 3 sensors, yellow, blue and black/brown. I think stage 3 is one of these sensors. It's definitely 3 stage as I've heard it come on in after-run and also when the rad sensor was faulty, and it's so loud you couldn't miss it.

[Keyo 47]

Yep 3 stage for sure , I can't see why the newer version of the fan controller would not work if it is three stage. there is also another fan controller unit that is cheaper then the late VR fan control unit that has an A on the end with the same part number before that, is a lot more common and therefore cheaper, maybe this will also work.

 

From a Golf Mk3 357 919 506 A

https://www.ebay.co.uk/itm/Vw-Golf-Mk3-Fan-Control-Relay-357-919-506-A/183964808325?hash=item2ad5283485:g:uQAAAOSw5SNdRHYS

Edited October 24, 2019 by Keyo

[Keyo 47]

It does appear that you can use a MK3 golf one as the part numbers are cross referenced on this aftermarket fan control unit.

 

https://www.ebay.co.uk/itm/New-VEM-Radiator-Cooling-Fan-Castor-Relay-V15-71-0032-Top-German-Quality/193131632550?hash=item2cf78ad7a6:g:IEcAAOSw6UlcpjuI

 

Manufacturer Part Number 1: FORD : 7203654, FORD : 95VW14B205AA, SEAT : 357919506, SEAT : 357919506A, SEAT : 3A0919506, VAG : 357919506, VAG : 357919506A, VAG : 3A0919506, VW : 357919506, VW : 357919506A, VW : 3A0919506

 

Has your part number on your existing fan got one of the above numbers?

Edited October 24, 2019 by Keyo

[Kevin Bacon 5]

There's 3 sensors, yellow, blue and black/brown. I think stage 3 is one of these sensors. It's definitely 3 stage as I've heard it come on in after-run and also when the rad sensor was faulty, and it's so loud you couldn't miss it.

 

Yeah, from memory.....

 

2 pin blue = engine ECU coolant sensor

4 pin yellow = Stage 2 fans and dash gauge - 105 ish degrees

2 pin black = Stage 3 fans - 115 ish degrees

3 pin thermo switch in radiator = Stage 1 fan and after run pump signal to fan controller - 95 degrees

 

I believe the Fan controller takes a signal from the yellow and black sensors, and stage 1 runs autonomously.

 

It's one hell of a system just to run some fans :lol:

 

Maybe MK5 GTI fans would be a good upgrade. The controller is built into the fan motor and just takes one signal from the coolant sensor. Much simpler!

Edited October 25, 2019 by Kevin Bacon

[tony_ack 0]

Have you fixed yours then Tony, if so what was it

 

It's half fixed - the run on issue sorted itself out which just left the fans coming on with the ignition. Pulling fuse 6 stopped it happening - I thought there was a crossed circuit somewhere as most fusebox guides say that fuse is just for the fresh air blower, but nope, buried in the late vr wiring diagrams, the circuit splits to send an ignition live signal to the fan controller. I found the connector behind the fusebox, disconnected the fan controller feed and the fans went off... I'd already changed the fan controller, so now the issue had to be in the signal circuits for the temp senders.

 

So I went back to disconnecting the senders, yellow and rad sender no difference, but the issue stopped when I disconnected the black sender - it must have been stage 3 that was coming on, not stage 2.

 

That's as far as I've got, I'm running without the black sender plugged in at the moment, next step is to order a new sender, plug it into the connector and see what happens. Or I have a brown sender in the garage (and new 4 pin connector) as I was planning to run aircon at some point.

 

Other electrical gremlins are okay for now - rear light turned out to be that I'd dropped a small nut into the rear light bulb holder when reassembling the car after welding and painting - that was shorting the circuit and blowing the fuse. Horn is working for now, not sure what was wrong here, though the temp sender wiring and horn follow a similar route down the chassis leg.

 

Sorry for all the detail, hope it helps though if someone is trying to diagnose a similar problem.

[fendervg 29]

It's half fixed - the run on issue sorted itself out which just left the fans coming on with the ignition. Pulling fuse 6 stopped it happening - I thought there was a crossed circuit somewhere as most fusebox guides say that fuse is just for the fresh air blower, but nope, buried in the late vr wiring diagrams, the circuit splits to send an ignition live signal to the fan controller. I found the connector behind the fusebox, disconnected the fan controller feed and the fans went off... I'd already changed the fan controller, so now the issue had to be in the signal circuits for the temp senders.

 

So I went back to disconnecting the senders, yellow and rad sender no difference, but the issue stopped when I disconnected the black sender - it must have been stage 3 that was coming on, not stage 2.

 

That's as far as I've got, I'm running without the black sender plugged in at the moment, next step is to order a new sender, plug it into the connector and see what happens. Or I have a brown sender in the garage (and new 4 pin connector) as I was planning to run aircon at some point.

 

Other electrical gremlins are okay for now - rear light turned out to be that I'd dropped a small nut into the rear light bulb holder when reassembling the car after welding and painting - that was shorting the circuit and blowing the fuse. Horn is working for now, not sure what was wrong here, though the temp sender wiring and horn follow a similar route down the chassis leg.

 

Sorry for all the detail, hope it helps though if someone is trying to diagnose a similar problem.

 

Fuse 13 (horn) also covers the aux water pump and radiator run on.

[Keyo 47]

Good luck with this Ant sounds like your well on your way to solving the issues.