The definitive VR6 cooling guide

[lewvw 10]

Ok, Now i've replaced the yellow (now black) temp sender in the thermostat housing, switched ignition on then off, still no aux pump.

 

Took for a drive to get engine up to temp, got home, ignition off still no pump, so I did as i have been doing and left ignition on to let pump run for 10 mins.

 

Then when I switched the ignition off to lock her up and start scratching my head again the bloody fans and aux pump came on!

 

Can someone please tell me whether I have fixed it or I need to further bankrupt myself?

[fla 9]

the aux fans on the afterrun is not something that will always happen and tbh if it is, then it means that there is still a fair amount of heat in the system. This may typically be after a lot of town driving, or immeidately after coming off and pulling up after a motorway run giving it some beans! So dont worry about that.

When you turn the ignition on, engine off can you hear the aux pump? Also, do your fans kick in at the right temps (iirc speed 1 84C, speed 2 105C, forget speed 3, it should not normally come on).

What are your water temps? Dont forget, fans are there to control the temp, not to set the temp, if you see what i mean. If it is not too high they wont come on. HTH

[RW1 0]

The temp settings are 93'C/88'C for the Yellow (black) sensor switch for the run-on fan and aux pump to trigger . If I get my coolant down to 90'C before stopping the engine, the run-on doesn't trigger.

 

If you want to be sure......

 

- Bridge the connector pins 1 & 3 with ignition off and check the aux pump and fans come on.

- Also put the yellow (black) thermoswitch/temp sender in water above 95'C and see if a circuit is made between its pins 1 & 3. If not = u/s.

 

The aux. pump / rad fans run not as a timed duration but as long as the thermoswitch is made.

 

The third stage fan is not triggered by the radiator thermo switch in the radiator side wall, but is in the far left sensor in the thermostat housing. Triggers around 112'C and you will know its on! To get that condition its German autoban speed driving and coming to a sudden halt or a tuned engine eg. supercharger.

Never managed thaty on mine yet, even on the hottest days we've had here in the UK.

 

.

Edited April 7, 2011 by RW1

[lewvw 10]

Cheers guys, yes my aux pump runs when ign switched on, stage 2 fans come on just before 100c (on the dash this is not always accurate?) so I think i'm missing stage 1, i've bridged the terminals on the four pin sender and fans and aux pump do come on.

 

---------- Post added at 06:35 PM ---------- Previous post was at 06:31 PM ----------

 

My gauge temp is normally just under 90 when driving, then just around 100 in traffic

[hendrikbmx 0]

hi all, I am about to replace my thermostat housing, along with all the parts around there, plus I got a GruvenParts crackpipe.

should I put any silicone between the plastic parts?

[attoycity 10]

wow that is really cool...

[too hot 0]

No don`t put silicone in the rubber seals are quite enough

[jonny-5 0]

Hi, my problem is that I have no stage one fan.

 

Ive bridged the connectors at the rad temp switch with ignition on and can only get stage 2.

I get no fan when the a/c is switched on.

No fan run-on at all.

Aux water pump works correctly and runs on correctly.

Fan speed 2 works correctly - turning on at 105 and off at 95 (check through vag com).

Don't think I've experienced stage 3 although I understand it's quite rare.

 

What should I check next?

Does anyone think this could be fan controlled issue?

[jakegti 0]

hi all, I am about to replace my thermostat housing, along with all the parts around there, plus I got a GruvenParts crackpipe.

should I put any silicone between the plastic parts?

 

yes put gasket sealer around the thermostat housing. they are a pain in the arse to seal

[toledo 0]

yes put gasket sealer around the thermostat housing. they are a pain in the arse to seal

 

Are they? , just done mine with no probs and i'm not normally a smartarse !! Lol

[swiftkid 1]

Right having some problems, seems my VR has gone from running 94-102 degrees to 110-120 degrees (oil temps) following obd2 conversion and 6 branch. Also I did used to get 300 miles to £60, my last £60 gave me 250 miles so im a bit confused whats happening. My theory is that the exhaust it blowing a little bit, especially when cold therefore causing more fuel to be injected and therefore obviously using more fuel but would this cause the oil temps to rise that high, and even though my mfa still reads 35mpg? you would think the car would know its injecting fuel like its going out of fashion.

 

I've checked the auxillary water pump and it doesn't appear to be running yet all the fans kick in as they should, would this somehow cause the oil temps to rise if the water isn't being pumped sufficiently even though the water temps are fine? *touch wood*

[mattwelcer 0]

Here is some additional information that might be useful.

 

VW also have two cleaning agents for the cooling system. One to remove oil and the other rust. Here are the part no. for both

 

G 052 188 A3 - cleaning agent for coolant circuit, deoiling (costs roughly 30€)

G 111 000 A3 - cleaning agent for coolant circuit, derusting (costs roughly 40€)

 

Both are 5ltr. and should be mixed 1:1 and then afterwards a thorough rinsing (can take several attempts!!!) should be performed to remove any left over cleaning agent.

Additionally this information may only be found in the additional catalogue(s) in ETKA (to help the parts guy :thumbleft: )

 

Special Catalogues --> Chemical Materials --> service fluid -miscellaneous-

 

The coolant level should them be topped up to the specified ratio using the current G12++ coolant.

 

As far as i know the deoiling agent is orange in colour I am not sure about the derusting agent, it may be the same.

Edited July 11, 2011 by mattwelcer

[fla 9]

good info Matt. I want to get rid of the crud in my cooling system too, its mainly rust deposits as its pretty bark brown. Will this all drain properly out of the outlet in the crack pipe?

 

---------- Post added at 07:38 PM ---------- Previous post was at 06:19 PM ----------

 

actuall;y just a thought, to get rid of rust you use a mild acid. Might try a load of white vinegar in the car and leave it overnight once its circulated. Any idea whether this will affect the seals - it shouldnt i gues as the pH is only around 3-4 and should dry them out. Will smell like a chipshop for a while though!

[Goggelogge 10]

Hi hope someone can help me otherwise I give up soon: (

 

I soon changed everything on my vr6'er:

 

thermostat

thermostat housing

all four sensors (yellow, blue, black and the rad detector)

 

but the radiator does not start before step 3 (112 degrees)

 

but if I unplug the fan when it is hot before step 3 there is power in the red / white and red / black but not blue

 

it must begin with only once in the red wire or?

 

what could it be otherwise hope to help read all 17 pages but no luck?

[RW1 0]

If red/white (1st stage) and red/black (2nd stage) have 12 volts at the fan connector and the 3rd stage runs.... Then the main suspect is the fan motor as with it running on the 3rd stage confirms the earth (brown) is OK. Stage 1 & 2 use electrical shunting to cut the speed down.

 

Don't understand your blue wire. The 3rd stage is red/yellow or red/green for 1995 model year and the wiring is the same for all VR6's from 1992 - 1995.

 

.

[Goggelogge 10]

okay thanks

 

it confirms my suspicion of it was fan

 

for yes the 2 red gives 12 volts when it is hot to the fan without it starts.

 

regarding the blue wire, I must be you answer honestly it goes up a cooler relay and there is a connection, have tested when it gets 12 volts direct drive fan stage 3 i think: /

[RW1 0]

I assumed it was Stage 3 for the blue wire but its not documented.

 

.

[Goggelogge 10]

Thx are there some cheap places ind england/germany to buy a new fan ?

[Supercharged 2]

Is the blue wire for an A/C component maybe?

[Goggelogge 10]

nope i dont think so becuse it goes in the relay : picture http://bilgalleri.dk/alb_vis.aspx?AlbumID=81879

[RW1 0]

Is the blue wire for an A/C component maybe?

No blue wire in that build either, in use anywhere or directly to the rad fan motor.

 

.

[neo3670 0]

Hello people, just finished reading through the whole of this thread! Interesting reading, but i am still unsure what to do as i can't seem to find anyone else who has the same problem as i currently have. So forgive me if i have overlooked it, but i need some advice. My 1995 vr6 seems to be running at normal temperature, and normally does exactly what its supposed to as described in this thread, except now, after start up from cold, when it reaches normal temp, if you switch off, the next time you start again, the stage 3 fan kicks in after a couple of minutes (sounds like a jet engine!),even though the temp guage reads normal, and the fan will stay on for at least 5 mins even though the guage goes down under half way to about 1/4!!!??? This happens everytime you switch on again after stopping the engine at normal temperature. The car doesnt overheat...ever. I can hear the stage 1 fan operate when idleing, and after the engine is turned off, it it is a little hot, the stage 1 fan will keep going, so no problems there, but i just cant work out why the stage 3 fan kicks in?? Any ideas? I have checked the 3 sensors for corrosion but all seem fine. Actually, now that I've just read what i put down, i would think it sounds like an air lock? What do you think? If so how can i check/ remedy that?

Edited July 30, 2011 by neo3670

[dalhalvaig 0]

Sorry if this is covered. I reckon the thermostat on my VR6 may be stuck open as the temp gauge shows about 70C all the time until in traffic, at which point it goes up to just over 90 and the fan(s) kick in. I am assuming that the fans are operating OK from what I've read here, so sounds like I need to change the thermostat.

 

I've had a look at the thermostat's location and am trying to figure out how to get access to it. By feel, I can only get to 2 of 3 of the fixing bolts.

 

Can anyone give me a clue as to how to get access? I'm guessing I need to remove some other parts, but don't want to start dismantling only to discover that I've taken off too much.

[Kevin Bacon 5]

The 3rd bolt is easier to get at when the hoses are all disconnected. If you don't want to spend the afternoon swearing, I really would recommend you buy some spring clamp pliers.

 

Your 70 deg issue could also be caused by a duff yellow temp sender. It's two senders in one unit. Pins 1 & 4 do the fans and booster pump and Pins 2 & 3 do the dash gauge.

[dalhalvaig 0]

Your 70 deg issue could also be caused by a duff yellow temp sender. It's two senders in one unit. Pins 1 & 4 do the fans and booster pump and Pins 2 & 3 do the dash gauge.

 

Would the gauge still show higher temps? Was just out in the car just now and it didn't show over 70. Then in traffic went up to 90 plus as the fans went on. So the gauge is getting a signal. Would the gauge get a signal if the yellow sender was duff?

 

Cheers