VR6 radiator fan won't stop

[QuasiRob 0]

The radiator fans on my M reg VR6 won't stop. They start as soon as I start the engine and just keep going.

 

I've changed the radiator thermo switch (see http://the-corrado.net/showthread.php?53962-Changing-the-radiator-thermo-switch-on-a-VR6 ) but it's made no difference.

 

Anyone got any ideas?

 

Cheers!

[Kevin Bacon 5]

Try disconnecting the senders with the fan running and see which one stops them.

 

Radiator sender, then Yellow temp sender

 

If they're still going with those disconnected, it will be a faulty fan controller box.

[hombre_paulo 0]

Yellow temp sender on the thermostat housing and the fan control module would be my next port of call.

 

Do you know what speed they are running on? 1,2 (3) if you have it. 3 will sound like the world is about to end

[QuasiRob 0]

Thanks for the replies. I would say the speed is "Stuka" cos it sounds like a dive bomber, so I guess that is a 3.

 

Where is the yellow temp sender?

[Kevin Bacon 5]

Speed 3 is controlled by the black sender. As Hombre said, that and it's yellow partner are in the thermostat housing, which is on the engine block behind the fan motor. A plastic shroud covers them, which you need to pull off.

[QuasiRob 0]

Found them. Removed the yellow and it made no difference. Removed the black one and it stopped the fan.

 

So assuming the black one only triggers fan speed 3 I should be able to drive around slowly with that disconnected (at this time of year)?

 

The sensor on the black plug looks like it goes into the radiator hose where it leave the engine block. How much work is it to change the sensor and what is the proper name of that sensor? Do I just ask for a fan controller speed 3? (at GSF)

 

What does the blue plug between the yellow and black ones do?

[hombre_paulo 0]

You`ll be fine with it not plugged in aslong as your cooling is in good order and seeing as its winter (it kicks in at 120c!) Dead simple to change, pull off the plastic cover, there`ll be a small metal clip holding access from on top, pull that up and out of the housing. Then pull out the old sender and quickly plug the new one in, hopefully you wont lose too much coolant but top up anyway. Dont go to gsf, I`ve had a couple of dodgy senders from there, it`ll cost more but the vag ones are better.

 

The sender in the middle provides the ECU with the coolant temp. If this is dodgy it will result in very poor engine running/fuelling

[mlyon89 0]

I've got a similiar problem with my fans on my VR. they seem to have a mind of their own. i think the problem is the condition of the multi plug that pugs into the main radiator fan switch at the bottom of the radiator it is quite badly corroded. i did try and clean it up the best i could when i changed the radiator and fitted my samco hoses but its started being tempermental again. the fans would just come on whenever regardless of ignition, on/off, fast slow! i think im going to have to cut out the plug and re wire in another one from another loom if i can get one!

[QuasiRob 0]

Excellent information, thanks hombre_paulo and kevhaywire, its much appreciated!

 

I'll get hold of a new sensor and give it a go...will I need to remove any other engine bits to get it out? OK, I could go look myself but the lights going and its wet n cold out! :)

[hombre_paulo 0]

You should be ok with just taking off the plastic cover on the thermostat housing

[Ice White Socks 0]

Yes i had the same problem- new black temp sender fixed the prob- best to get a new rubber seal as well - the old ones go hard and don't reseal properly- also to remove you just need to unclip the metal clip that holds the sensor in- but fiddly to get back but do-able

Edited February 23, 2011 by Ice White Socks

[hombre_paulo 0]

Hey Quasirob, did this sort out your issue?

 

It's nice to get the results of queries added to threads for anyone else searching the same issue

[Critical_Mass 10]

Try disconnecting the senders with the fan running and see which one stops them.

 

Radiator sender, then Yellow temp sender

 

If they're still going with those disconnected, it will be a faulty fan controller box.

 

 

Would these cause the fans to run irratically too?

 

On mine when i turn the ignition off after a run, sometimes it doesnt come on at all, other times it comes on for a matter of minutes then switches itself off and other times it will come on for about a second then switch off then back on for a second and back off... sees random.

 

Or would this be more the control box thats faulty?

[fla 9]

actually its not a bad thing if your fans dont come on after a run - means your cooling system is working well enough to keep the coolant at the right temp. Mine behaves similarly to yours Gaz, ie it sometimes comes on after a run for about 20 secs, sometimes not at all, occasionally stays on for about 5 minutes in summer after a blast.