The definitive VR6 cooling guide

[volksworld13 0]

you ideally need a coolant pressure tester.and then check for leaks. when you have manually pressurised the cooling system a leak will shows itself on the guage and or leak.

[P3rks 11]

I've just been playing around with my fans just to make sure everything is working ok after my OBD2 conversion due to the fact my heatermatrix popped within a few weeks of it being back on the road and I wanted to make sure the cooling system is spot on.

 

I've followed the guide as of page one to test everything and I bridged the connections on the radiator switch; stage 1 and 3 are good. Stage two, nadda, nothing.

 

Bridging the yellow temp sensor activates the Aux pump and the fan. The aux pump works on ignition, when running and on after-run for approx 10 minutes. The fans also work on the afterrun.

 

The stage one kicks in around 90-95°C (according to the clocks and vagcom (blue temp)).

 

The car never really goes above 100°C at all. So I don't know if stage two ever kicks in.. I just don;t want to be in a position where I need stage two and it isn't there..

 

Oh.. I also tried a different blue temp, yellow temp and fan control module with no different effect.

 

Where do I go from here?

Edited July 2, 2013 by P3rks

[dil 0]

I thought there was only 2 stages, if you got fans on both bridge attempts of the rad switch block I think your good.

[P3rks 11]

Apologies, I'll clarify.

 

I have the later type rad switch. If I bridge the common wire (red/white) with the red wire I get stage 1. If I bridge the common wire with the red/black wire I get nothing. According to the guide I should get stage 2.

 

If I bridge the connection from the black temp sensor I get stage 3.

[P3rks 11]

Right..

 

Just double checked the wiring diagrams and as it stands the first page is incorrect.. For my car anyway (late 1993 VR6 - Essentially 94 model spec)

 

 

Fans check

1. Take the plug off the rad sender

2. Take the plug off the black temp sender in the stat housing.

3. Switch ignition on.

 

In the rad sensor plug - red wire is stage 1, thin red/black is stage 2. The other wire is the common connection. Bridge each of the two wires in turn across the common wire and see if both speeds come on. If they do, good.

 

4. Bridge the black plug with a paper clip or something, does stage 3 come on? Sounds uber loud!

 

 

On my car and VW wiring diagrams for the 3 speed fan. The Red wire on the radiator sensor is permanent live. Red/White is stage one. and Red/Black is Stage two.

 

If I bridge the wires Red with Red/White I get stage 1. If I bridge Red with Red/Black I get stage 2.

 

I traced the connections from each source for the stage two and tested the wire continuity and everything seems fine. I then waited for my car to get up to temp and tested the outputs from the fan control module to see which fans were kicking in. I get stage 1 and stage 2 kicking in. All is good. :)

[redheadmarshal 10]

Hi all, hoping for a bit of advice. My VR6 recently started losing coolant from somewhere, I eventually found the source of the leak after it had been MOT'd (failed) so had been running for a while. Looks like the leak is coming from the 90-degree connector shown in the photo, I'm guessing it's a seal inside that's failed. My question is, is this part readily available?

[ATTACH]75011[/ATTACH]

 

The garage that did the MOT had a look at it for me and said they were struggling to find it anywhere; they also noted that the bolt holding this in place has rusted solid, so removing it may well break the vertical pipe that this connector fits into. Second question is therefore, is the vertical section that this joins to also available?

[GusPW 0]

the elbow and seal are available from vw heritage or vw classic parts.

sometimes on eBay as well.

 

not sure about the vertical bit it bolts into but looking at it it'll probably come out fine.

[P3rks 11]

As above.

 

Classic parts or VW Heritage Classic parts for the elbow and seal.

 

The elbow bolts direct to the radiator. So if the bolt snaps or crack the housing it's new rad time.

 

WD40 or similar soaking for ages. Then I'd get the car hot and up to temp before trying to remove it.

[redheadmarshal 10]

Thanks for the advice guys, elbow is now en route from VW heritage. Someone has suggested Coca-Cola as a surefire way of loosening a stuck bolt, but I think I'll put my faith in WD40!

[redheadmarshal 10]

The story continues - the elbow came off without too much trouble after several applications of WD40 to the rusted bolt and a brief moment of panic as to whether I'd see the whole bolt coming out or a jagged stub. Having removed the elbow, the vertical section below it is most definitely holding coolant as it was basically full, to the point that as soon as the elbow was removed the coolant then started to dribble all over the floor from the top of the vertical pipe. Surprised that there would be so much held in that section though - would this suggest a blockage of some sort further along the system? That would explain why the level in the tank is so low, and the leak, as if the system is blocked the extra pressure caused might be enough to cause the leak I spotted round the elbow connector. Anyone else had a similar issue?

[VWVW 1]

The story continues - the elbow came off without too much trouble after several applications of WD40 to the rusted bolt and a brief moment of panic as to whether I'd see the whole bolt coming out or a jagged stub. Having removed the elbow, the vertical section below it is most definitely holding coolant as it was basically full, to the point that as soon as the elbow was removed the coolant then started to dribble all over the floor from the top of the vertical pipe. Surprised that there would be so much held in that section though - would this suggest a blockage of some sort further along the system? That would explain why the level in the tank is so low, and the leak, as if the system is blocked the extra pressure caused might be enough to cause the leak I spotted round the elbow connector. Anyone else had a similar issue?

 

Does your elbow connector still have a rubber O ring around it.

[redheadmarshal 10]

Yes, the rubber o-ring seal is still on and intact (I'd expected that to be the source of the problem)

[Dan_Storm 0]

I think there is an error on Dinkus' post on page 1.

 

In the rad sensor plug - red wire is stage 1, thin red/black is stage 2. The other wire is the common connection. Bridge each of the two wires in turn across the common wire and see if both speeds come on. If they do, good.

 

On my Corrado the red is common, red/white is stage 1 and red/black is stage 2. I checked in the Bentley manual and it states the same. Can someone else confirm? Not sure if maybe some got wired the opposite way, wouldn't surprise me :)

Edited July 23, 2013 by Dan_Storm

[daves16v 1]

I think there is an error on Dinkus' post on page 1.

 

 

 

On my Corrado the red is common, red/white is stage 1 and red/black is stage 2. I checked in the Bentley manual and it states the same. Can someone else confirm? Not sure if maybe some got wired the opposite way, wouldn't surprise me :)

 

Yep I've noticed the same error.

[Goldie 2]

Without going through 24 pages of stuff how much coolant should i put in. We are up to G13 now, i doubt this is really any different...

[unclean 10]

This guide was really useful debugging what I now think is a dead rad sensor. Just as an amendment, when testing the fan the guide says "In the rad sensor plug - red wire is stage 1, thin red/black is stage 2" and the common is the other. It actually appears that the solely red wire is the common and the red/white is stage one and red/black is stage two.

 

This is corroborated in this Bentley diagram (thanks Stonejag)

 

[Roger Chatfield 0]

Fella's, I'm a little confused about the running of the aux water pump.

 

Mine runs all the time the ignition is on which I assume is normal.

I doesn't run if the ignition is off... unless the engine is hot and the rad fan is running, the fan and pump runs for about a min then both switch off (I assume when the engine is cool enough).

 

Is this normal?? just that I read in the first page of this thread that the aux pump should run of 10 mins after ignition switch off.

 

Rog.

[daves16v 1]

Rog, sounds fine to me. The aux pump and fan run for as long as needed with engine off. Runs this way on mine.

[Jon_vr6 1]

Agreed only really hear it running (after ive turned the engine off) when its really hot summertime scorchers

[Roger Chatfield 0]

Maybe we should amend the first page, it says the pump should run for ten minutes after the ignition is switched off regardless of engine temperature.

 

Rog.

[robrado974 1]

As above Rog , mine runs for as long as it needs to .

[unclean 10]

Maybe we should amend the first page, it says the pump should run for ten minutes after the ignition is switched off regardless of engine temperature.

 

Rog.

 

Mine behaves in exactly the same way as yours Rog and I agree the first page is confusing.

 

With further reading elsewhere, the *controller* always stays on for the ten minutes after running the ignition; which allows the fan and pump to be powered on for up to ten minutes or until (which should be the case) temperatures are lowered sufficiently.

 

When the ignition is on, the aux pump will always run.

 

EDIT: This is another guide which is very similar, but a bit clearer - https://sites.google.com/site/stoyneff/miscellaneous/the-vr6-cooling-system

[jamesoff 10]

Is there a version of this thread (or a similarly comprehensive collection of information) for the 16v? Mine's running warm (I think) and while I can apply some of the general stuff from the OP obviously quite a bit of the specifics are different.

[VW_chris 10]

Any ideas as to what this could be guys? My stage 3 fans come on after exactly 10 seconds regardless if it's hot or cold????

[fla 9]

Anyone know what the resistance of the rad sensor should be?

My fans aren't coming on although bridging the red & red/white switches them on. That said bridging the other two does nothing. I'm guessing that the rad sensor is shot although it was replaced about 10,000 miles back so i would be surprised if its already toast.

 

I've got two spal fans wired, with speeds 1 and two bridged on the main connector. Fuse 19 is ok, as are the fuses in the fan control module.