VR6 Raditor Fan Wierd

[courtz1976-2dr]

Hi there All,

i am having a strange issue with my radiator fan - let me run through the scenarios

in all scenarios AUX water pump runs at "right" times

1. Engine ON, At operating temp, AC ON, Fan runs full
2. Engine ON " AC OFF Fan does not run - temp climbs to 90-100 still no fan.
3. Engine OFF (ignition off) temp 90+ fan runs and shuts off when temp reduces to around 85-90C
4. similar to 3 ignition on, temp at 90+ fan not running
5 similar to 4 ignition off, temp at 90+ fan runs and turns off


????????

Any pointers or testing procedures that I can take to isolate the culprit.

Any help would be appreciated.

Cheers and Regards,
Courtz.

[The_Hawk]

Hi there All,
1. Engine ON, At operating temp, AC ON, Fan runs full
2. Engine ON " AC OFF Fan does not run - temp climbs to 90-100 still no fan.
3. Engine OFF (ignition off) temp 90+ fan runs and shuts off when temp reduces to around 85-90C
4. similar to 3 ignition on, temp at 90+ fan not running
5 similar to 4 ignition off, temp at 90+ fan runs and turns off

I had wierd issues with my thermo fans too which I linked back to the AC not working. Now the AC is fixed the fans work right.. I think.

According to Bently the fans in the VR6 come on at:

Low Speed Fan : 92-97C
High Speed Fan : 99-105C


I also understand that there is a switch in the AC pump that turn on the high speed, so fans on high with the AC is normal as temps go up. (mine cuts in and out at lower temps but always on high speed).

so
1. Normal
2. Your low speed should be on
3. Normal - After Run fans on
4. Possibly normal, fans not needed unless over 92C
5. See 3.

[courtz1976-2dr]

I dont think I have let it go to 99-105, if I see this in "normal" slow traffic situations I am quick to turn the AC button on to bring it down ASAP.

I am of the understanding that 100C is boiling point and this is BAD causing air locks and undue pressure with chance of bursting pipes...

But it seems that the Vr6 runs HOT,I have had it go to 105C and it appears to be getting hotter (when not moving, hard driving - come to idle ie waiting for traffic) (this happens pretty rarely) and this is when I reach for the AC control to bring it back down to the 90's. From what you tell me this seems to be normal.

When I attempt to test - I let the gauge go to 90 and think that this is when the fan should be kicking in, when I dont see it kick in I start the AC, maybe I am just being a little paranoid - I will let it go a little higher to see of the fan operates at low speed and then 100+ to see if it goes into high speed mode.

Thanks very much for the info - I am used to the little 76 swallowtail that very rarely goes past "normal"

When running (cruising) it sits at a pretty steady 80c, even when I flog it at 180 (shhhh)

Cheers

[courtz1976-2dr]

According to Bently the fans in the VR6 come on at:

Low Speed Fan : 92-97C
High Speed Fan : 99-105C


so
1. Normal
2. Your low speed should be on
3. Normal - After Run fans on
4. Possibly normal, fans not needed unless over 92C
5. See 3.

OK - update

I reluctantly let the temp climb to 95c and still no low speed fan so I let it go to 100....105....110....just past 110 and I couldn't take it NO fan at all at these temps, turn the ignition off and up fires the fan.

Now correct me if my reasoning is wrong

the sender resposible for telling the fan to run after OFF must be different to the sender telling the fan to run when the car is running.

This must be the thermoswitch in the radiator itself????? not the ones housed in the thermostat housing?????

so by rights this is a bimetallic strip thingy that will cause a short between pins and tell the fan to run????

so I should be able to get the fan to fire up when the car is running by shorting some pins??? on the connector (let me know now before I fry something in the ECU)

is there some other way of testing the fan/thermoswitch/control module????

Please help - it is getting above 37+ ambient temps up here and sitting still for a while in traffic is hopeless - and considering the AC does not pump out cold air (probably needs regas) turning on the AC fan pumps hot air at me making my eyelids stick to my eyeballs LOL

[The_Hawk]

Yeah, the VR6 has 4 temp sensors, just to be different.

Your going to make me think now...

Here is three of them from an earlier post I had:
Original post: http://www.vwwatercooled.org.au/newf...ead.php?t=8339

According to Bently's:

The three plugs from left to right are:

1. After-run coolant fan control thermal switch (F87) and ECT sensor (G2).
2. Engine Cooland Temperature (ECT) sensor (G62).
3. A/C Cutout thermal switch (F163) and third speed coolant fan control thermal switch (F165)

1. Should control the thermo fans and the thermostat after the engine is stopped (or while it's on).
2. Sends the temp to the guage / ECU.
3. Should work with the AC to turn on the thermo fans when the AC is on. (or when the car is hot)

So it sounds like maybe the sensor on the right is bung... but then there is the one on the radiator as well.

In my travels to fix my fans/AC I bought the sensor that goes on the radiator itself for $80 from VW Liverpool. Never installed it as I didn't need it, so it's still brand new! If you decide you want it, $50 and it's yours inc postage anywhere in the country.


Note: I have since found out that the yellow sensor was replaced (updated) to a black/blue sensor at some stage, although I have only ever seen a yellow one myself. So if yours is a different colour, thats normal.

[courtz1976-2dr]

Yeah, the VR6 has 4 temp sensors, just to be different.

Your going to make me think now...

Here is three of them from an earlier post I had:
Original post: http://www.vwwatercooled.org.au/newf...ead.php?t=8339



So it sounds like maybe the sensor on the right is bung... but then there is the one on the radiator as well.

.

This is getting confusing when I pull the far left sensor (yellow) the guage dies - pull the blue nothing - pull the brown (mine is white) nothing, in regards to the temp guage it goes to far left.

To tell the truth I dont think I have seen the fan run on anything but FULL BORE.

And when mucking around with these connectors I felt that the silverish cover plate on the fan motor was hot, "pull your hand back quick and manage to cut your hand on something sharp hot" so I am not sure if this is normal - I have read that there are internal resistors responsible for regulating the speed of the fan.

How do I "hard test" the fan to see if it is indeed even going to run on the other speeds.

[The_Hawk]

oh, I also forgot to mention the fan controller thingy which is under the water bottle and has plugs coming out the bottom...

In my case I went and saw Golf Loon (Matt) @ Camden GTI and we swapped out each part with known good ones to see what effect they had.

We didn't actually install them, but plugged them in... in theory they then read ambient temp and should turn the fans off. Since my problem was fans stuck ON, that worked for me.

It's painful I know.

Where are you located anyway? We might be able to point at a reputable mechanic who can give you a hand.

[Golf Loon]

Courtney

Get the AC fixed as the compressor has 2 switches in it which help control the fans. Get the compressor rebuilt, I can help if no-one up there can.
Second hand compressors are a waste of time on a VR6 being as they are a **** to change.

Worse case scenario, you do that and you end up with working AC and the fans are still the same.

If that is the case, I`d change the box of tricks up under the bottle. Dont try and short wires out, you will fry things.

You should be able to put power to the different terminals on the connector on the fan motor to test that out.

Glad that thing is still running around and that you are still here.

Update your location details mate.