The definitive VR6 cooling guide

[Samaj 0]

This is by far the best compilation on anything & everything related to the generic VR6 heating issue. Thanks to everyone who have contributed especially to the originators of this post! :clap:

 

My issues.......but first the current specs.

 

-1992 Corrado VR6 , Manual, Engine spec AAA US spec, With A/C,Milage 72K Miles.Stock car except for Samco hoses (installed by previous owner)

-Recently changed the Radiator Fan control unit to the OE VW uprated part no. 3A0919506 (10 pin).

-Now the radiator fan kicks in directly only at the 3 speed. The fan does seem to kick in at about 110 degree C water temp.for about 1 minute only.Not enough for the temp. to drop.

-The 1st & 2nd speed dont work. To remedey this temp. i have fitted an manual indash switch for the 3rd speed. If i dont use the manul fan switch the water temp hits 110-115 C,oil 110-120 C.

-Switch the fan & the water temp stays on or below 91 C & oil at 85 C. Which seems to be normal from all that i have read here.

- The fan dosent seem to run or I cant hear the auxiliary coolant pump after i switch of the engine either.

-My mechanic says that the radiator fan motor's speed controller thingy (apprently mounted on back of the motor itself ) is bust hence i dont get 1st & 2nd speed....?

 

Any ideas...?

 

Thanks in advance

[jpowell79 0]

I recently changed my thermostat switch, and now I get stage 2&3 fans, but not stage 1.....the 5amp fuse keeps popping, so am guessing it might need a new controller :scratch:

[MattPc 0]

Hi, I'm looking for some advice on what size oil cooler and thermostat temp to go for on my VR6. My current oil temps are good at 90-102 motorway cruising depending on speed, in traffic I can somethimes see 106-108degC (I haven't sat in 22degC + ambiant air temp yet). At some time in the future I will upgrade: cams, remap, exhaust and inlet manifolds & pacet slim radiator fans and I can see the oil temp getting quite hot, as I plan to do a couple of trackdays and other events.

I will be keeping the OEM heat excahanger for initial heating of the engine oil, on engine warm up, and using the additional heat exchanger for cooling at the higher running temperatures. I am currenlty looking at 10 row 235mm & 13row 235mm heat exhangers connected to a thermostatic plate with either a 80degC or 92degC thermostat in and I'm just wanting some pointers as to choosing the right configuration for my current/future setup.

Also if anyone has a current setup, what temps do you see on track with similar modifications?

 

Cheers

Matt

[aide 0]

on my last vr i used a 13 row cooler, removed the oem cooler and used a thermostatic plate, on a standard vr i saw temps drop from 118degs to high 90's, that was motorway cruise speed when i lived in devon - i.e. warmer than here :lol:

 

surely the thermostatic plate allows the oil to heat before it activates, from memory i'm not sure both will fit on the spindle in any case.

[MattPc 0]

I can get a spindle from C2 motorsports to fit both OEM and aftermarket plates.

[PaulMoVR6 0]

ok bit of advice needed

 

i have finally got to the bottom of my dodgy water temp readings, the car now reads about 92c while cruiseing but when i am stuck in traffic the gauge will go uo to just under 110c, iam thinking stage 1 of the fans aint comeing on? whats the best part to replace first? rad switch?

 

Paul

[Critical_Mass 10]

ok bit of advice needed

 

i have finally got to the bottom of my dodgy water temp readings, the car now reads about 92c while cruiseing but when i am stuck in traffic the gauge will go uo to just under 110c, iam thinking stage 1 of the fans aint comeing on? whats the best part to replace first? rad switch?

 

Paul

 

Sounds like stage 1 isnt working yeah. what was the gauge issue anyway?

[PaulMoVR6 0]

how do i go about fixing it so i have stage 1 working mate? rad switch?

 

well my gauge was misbeheaving it was shooting up off the scale when the car was started even if it had been sat for a few days, so i got another set of dials this is my thrid and also swaped my newer black temp sender to a older yellow one this now shows about 92c while cruiseing, but just a bit paranoid about it riseing while in traffic,

 

Paul

[Critical_Mass 10]

From Page 1 -

 

The main fan control temp sender is screwed into the radiator. This is a 3-pin brass jobber and has 2 different pin layouts depending on if you have early/late VR. It looks like early ones are all 3 pins in a row, late ones are 3 pins in a triangle shape.

 

One pin (not sure what colour, probably brown) is earth.

 

Pin 2 (thick red) is stage 1 output and is full-current to the fan. It has the following switching temps:

Switch On: 92-97 C (198-207 F) - officially rated at 95 C

Switch Off: 84-91 C (183-196 F) - officially rated at 84 C

 

Pin 3 (thin red/black) is stage 2 relay-switched output, which has the following switching temps:

Switch On: 99-105 C (210-221 F) - officially rated at 102 C

Switch Off: 91-98 C (196-208 F) - officially rated at 91 C

 

So yes rad switch.

 

Ever since changing my yellow temp sender to cure a gauge issue the fans used to come on every time i turned the ignition off but only once the car was up to temperature. Then one day they stopped doing it. :lol:

 

If you want to check if the fans are working. Idle the car and get it up to temp then just continue to let the temp rise and see if the fans come on at said temps.

[Nic 0]

Hi all, when the ignition is switched on the full stage 3 fans come straight on, have disconnected the black temp sender in the thermostat and the stage 3 fans don't come on, just to confirm the black temp switch is borked yup?

 

Also have this wire loose in the engine bay

 

 

It is loose under the main fan in a sort of cable tidy, also has a blue wire in the same area, can get photos if needed to explain better, can't see where it goes, any advice or suggestions as to where it goes would be gratefully appreciated!

 

Thanks,

 

Nic

[craigowl 0]

I believe there is a spare connector hangs about in the UK VR6 which is spare. Often reported on here - others will come on and confirm, I am sure.

[MattPc 0]

This might help

http://the-corrado.net/.archive/forum/viewtopic.php?f=1&t=91757

 

Matt

[Nic 0]

That's superb, thanks a lot!

[Kev_VR6 0]

Hi all!

 

I've recently discovered I have the 'rattling diodes' problem in the Fan Control Unit, but unfortunately both have come loose and I don't know which way to solder them back. Can anyone shed any light on this?

 

The fuse on top of the box had blown but for some reason my Revotec fan always came on at 92 degrees like it was supposed to, presumably just stage 1. The car never got too hot once I'd had these fans fitted...

 

I'd just buy new but I've been ringing round and no vw dealers have any left in the country as the part became obsolete in 2008. The part number stamped on the unit is 1HO 919 506. I have seen similar control units for sale on eBay with extra characters on the end such as ...506A and ...506B. Would these work instead?

[Batmanan 0]

It seems as it's my turn to have some problems with this, my car is a 93 VR6.

 

It started of the same as most people's with the fans not working at all, so after reading this thread I found that the first place was to check the stage 1 temp sender. Firstly my wiring is different to what was laid out on pg 1 of this thread as all the wires are the same size and the colours are Red, Red/Black & Red/White. I got 12v on the Red wire and nothing on the other 2 pins and i'm guessing that the Red/Black wire is the earth. Please can someone confirm this?

 

However i did try bridging between the Red & Red/Blk pins but got nothing. So it cant be the sensor at this moment so i looked at the motor and thought i would check the connections there. Somehow on this connector the Brown wire had practically burnt in two with just a little of the plastic shield holding it together. This is the big oblong connector that goes into the back of the fan motor, has anyone ever rewired one of these? I guess i need to pull all the terminals out strip all the wire's so they are the same length and redo them as opposed to trying to patch the brown wire back up. is there an easy way of removing the terminal's?

[Abdul 0]

Hey guys, ive just bought a vr and tend to sit in a lot of london traffic. Im wondering if anyone could perhaps give me a step by step guide on how they made their speed 3 fan switch? If anyone wants to make me one pm me a price as thats even better lol. Also, any pics of said switch mounted on ur dash?

 

Next question, are samco hoses a worthy investment or shall i stick with the vag stuff?

 

Thanks,

Abdul

[buttles 0]

Batmanan, the red wire is the common live, the red/white is Stage 1 and the red/black is stage 2. The guide on Fans check on page one is indeed slightly incorrect for ABV stuff.

[Roan 0]

Having read this guide and just about everything else regarding the VR6 cooling system, my car is still leaving me a bit confused.

 

My coolant temperature climbs to 105 before the fans kick in - could this be due to a faulty/gunked-up radiator switch and/or yellow sensor or something more serious?

 

I bridged the stage 1 contacts on the radiator switch plug and the fans came on, bridging the contacts for stage 2 resulted in nothing happening. Could this also be a faulty fan control module?

 

I have VAG COM arriving next week sometime so I suppose I should wait until I've scanned the car but if anyone could shed any light in case the scan shows up nothing I'd appreciate it.

[RW1 0]

VCDS doesn't look at the cooling fan circuits.

 

.

[G-Lad 0]

My car has always run hotter than I would have liked, but it seems to finally be under control.

 

So far in the last 18mths I've (in no particular order):

 

- Replaced the fan control box

- Replaced the thermostat and housing twice

- Replaced all three housing sensors

- Replaced the main water pump

- Replaced the electric after-run water pump

- Replaced the Oil temp sensor

- Replaced the Radiator coolant temp sensor

- had an acid-flush done on the block and head

- Added water-wetter to the new G12+

- Swapped the clocks (coolant was under reading / wouldn't go over 95, plus suspected over-reading Oil)

- Changed the oil from Synta Silver (10W-40) to Motul X-cess 8100 (5W-40)

- Fitted 6 new NGK BKR5E plugs

 

The water wetter took off 4-6 degrees on the oil guage, the oil lost me another 2-4 degrees and the plugs seems to have improved the power delivery, meaning I rag the car a little less ;)

 

...so the moral of the story is: Yes do replace long term service items like the sensors & thermostat, and indeed the water pumps if like me you find the fins of the impellers have partially broken off! But, don't forget the oil, plugs and actually checking if your clocks are telling you the truth by swapping a different set into the car and taking it for a drive!

 

Good luck all!

 

 

Chris

[MattPc 0]

Hi,

 

Does anyone know the mass flow rate of the standard radiator fans?

 

Cheers

Matt

[Skimask 0]

I've had an intermittent problem with my VR throwing coolant out of the expansion tank. Sitting in traffic the temperature would rise to 110 on the gauge, normal running it would always sit around 70.

I tried the usual, new expansion cap and seal. no effect. New expansion tank - again no effect. I hadn't heard the fans coming on, so checked them today. Bridging the wire ont he temperature sender plug at the radiator, the fans run fine. I couldn't remember hearing the Auxillary water pump. Stripped off the end engine cover and noticed the wires coming out of the electrical connector to the pump were bared. I checked the voltage at the connector and it was OK.

Decided to replace the plug as I had a spare.

Gave it a wee run and the temperatures are back to normal - just below 70 deg on the dial!

I reckon the pump was not working, the temperature was high and it would spit the water out of the expansion tank. Also because it wasn't working, it was airlocking in the heater matrix. Again making the expansion tank bubble over.

 

So - a simple fix for throwing water out of the expansion tank!

 

I've ordered a replacement Rad switch (just in case) as I don't think that was working either.

[robrado974 1]

glad this is here as the part no's at tps seem to be wrong . i now have the four senders i need , great thread , regards rob .

[lewvw 10]

I recentley noticed that my Aux pump did not run on my 95 Vr6, so I replaced it, cleaned corrosion from the multiplug, still wouldn't work so i checked the Fan control unit and replaced the 5amp fuse. The pump now runs when ignition on but doesn't afterrun for 10min like it's supposed to? I'm thinking the next step is to bridge the b and d terminals on the yellow sender in the thermo housing and if i get fans and pump then wiring is ok and sender is faulty? If they don't come on I need a Fan control unit?

[lewvw 10]

Hi guys, I have a 95vr6 and recently noticed that the aux pump wasn't going at all, i checked it and it was seized and corroded. I replaced the pump and the blown 5a fuse on the fan control unit but it still won't afterrun when the ignition is switched off even when engine up to temp. I am under the impression that if I bridge the b and d terminal on the yellow temp sender and get fans and pump then I need a sender but if not I need a control unit?