The definitive VR6 cooling guide

[nrc 0]

From the first post:

 

As the sump needs to come off to get at it, you're best replacing the sump gasket too. This is quite expensive (circa £35) and does change depending on car vintage. Early cars use VAG part number b021103609. Later cars use VAG part number b021103609B. No, I don't know what the difference is :(

 

I was chatting with one of the chaps at TPS this week when I was picking up a new sump gasket and he said the older fibre (cork?) gasket has been obsoleted in favour of the rubber type. I hope this is the case as mine should have been on the older type :) Also, it was £33 with VAT.

[RW1 0]

Bolt length changes between the gasket types. Fibre to rubber will mean the bolts are shorter in length. Hope there's enough threads for tightening otherwise you could strip the block holes.

 

Rubber ones aren't as good as the fibre. I went the other way with a PAYEN JH5013 fibre gasket. £16. So far so good.

[Stonejag 10]

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.

Cheers for this - mine is doing the same thing. Temp gauge stays stuck at the bottom of the scale for a loooong time; even after a good thrashing it only rises by a couple of mm (indicating 75ish). The fans don't come on at all and I can't hear the aux coolant pump when I turn the ignition on and off - but both of the fans do come on when I short brown/red to brown on the yellow sender's plug. They're so loud I've no idea if the aux pump is knackered or not The radiator and inlet manifold are both scorchio when it's been running for a bit so I'm guessing it is getting up to temperature - I just don't know what it is! (my fuel consumption is crap so I'm guessing the ECU doesn't either...)

 

Last time it was in, the garage claimed they replaced one of the temp senders but I'm not sure which one...I do have a spare yellow one so at least I have something to try!

 

Stone

[Moreland 10]

Ok, though't I'd post up as the VR's having some issues. The main issue I've got is the oil temp, major high readings from from 130deg @ 70mph to 160deg @90mph. I had a water temp issue which was sorted with a T'stat but I also changed the water pump, dash sender, fan switch and now coolant sits at around 85deg or so which should be ok.

 

The engines a replacement after the head went on my other one so I don't know what it was like before, it's not missed a beat in 3k miles so I don't think it's damaging it. I've got a oil temp sender coming Monday so will check the wiring when I take the inlet off. If that doesn't sort it I'm left scratching my head!

 

Not really related to cooling but I've got an electrical issue as well. When the keys in the ignition first stage without starting the engine, the fuel pump relay has a burst of power going to it from most of the interior components when there turned on, wipers, interior light, indicators, heater fans etc. This causes the relay on the fuel pump to click up to 10 or so times. Once the engines started though it stops and is fine to drive? I've changed the fuse box after the headlight loom burnt out and think that's when it started, could one of the auxiliary plugs be in the wrong place? It's a right mystery to me as I checked for bridging wires with no luck.

 

Thought's on both issues would be a great help, thanks

 

Paul

[RW1 0]

Latest prices........

 

If you want to use the original coolant concentrate G11 as supplied to VW, its in the list. Made by BASF and sold as Glysantin G48. Comma market it in 1ltr, 5ltr & 20 ltr quanties and is marked G48.

 

[ATTACH=CONFIG]49708[/ATTACH]

 

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[Stonejag 10]

I flushed my (auto) gearbox on Friday - there was barely any fluid in it at all and it was soot-black so it obviously needed doing! As well as my gearchanges being a lot smoother, especially when cold, it seems to warm up a lot better now - instead of the gauge sitting against the endstop all the time it comes up to believable temperatures even though my thermostat still needs doing. The stock tranny cooler is infamous for contaminating the ATF with coolant - could my lack of ATF have been causing an airlock in the coolant circuit?

 

Whatever happened, I'm much happier with it now!

 

Stone

[fla 9]

no, the auto cooler is just an addition in the cooling circuit. The atf is a separate circuit, so even if the cooler had failed that would only result in contamination not an airlock. When you drain the cooling system, flush it through until water runs clear. The fill it up with about 6 litres of spirit vinegar and run that in the car until it gets up to temp. Let it circulate and then leave it overnight. The drain, reflush with clean water and make up a new coolant using deionised water and G12++ (which you can get from GSF).

[OllieVR6 0]

Quick question, is G12+ or G12++ the stuff to use in a VR? I'm flushing are replacing my fluid tomorrow and I've just read that G12++ is only for alloy blocks (the post was from 2007 tho!).

 

Ta.

[daves16v 1]

I use G12++ in my VR without any problems. AFAIK you can only buy G12++ unless someone knows different.

[alex303 0]

Hi, could someone answer a quick question for me as i've had a good read thru this thread yesterday, does the Blue Temp Sender in the 12v VR signal the ECU to turn OFF the Cold Map i.e. did some searching also yesterday & it sounds like this is the case but i'd just like to be sure.

cheers, Alex

 

Blue, 2-pin plug. VAG part number 025 906 041 A (about £8, plus O-ring N 903 168 02)

[Kevin Bacon 5]

Yep. 70 deg C is when the warm up map switches off and the lambda kicks in.

[alex303 0]

thanks Kev!

 

Yep. 70 deg C is when the warm up map switches off and the lambda kicks in.

[gingernuts 0]

Right I'm at a wits end so hopefully someone can help me here before I bin the car!

I have 1993 2.9 vr that blew a head gasket a few months ago. I had this done and Since then It has been running hot when driving at slower speeds or traffic. it will sit at 90 when cruising/pushing on. In traffic it would creep over 100.

The fan will come on but only briefly

I have changed:

Aux water pump

Water pump

All sensors

Fan control module

I have bled it numerous times

And finally put a manual switch on with 2 stage control

 

I was reluctant to put the fan switch on but it was becoming a last resort. Its cold where I live at the moment yet it will still go over 90 when cruising slow or in traffic. I even tried just sitting with the engine running and the fan on stage three and it still crept up to just under 100.

 

It does have a r32 sump and pick up on it.

 

HELP! I'm losing the plot with this now!

[alexvr6storm 10]

Took my newly purchased VR out for a run at the weekend, just a quick 15 minute thrash (after she had warmed up) , noticed the fan stayed on for a good 3 minutes after turning her off, is that normal?

[GusPW 0]

Anyoneknow the part number for the rad thermoswitch/sender. Can't seem to see it in first post and been searching for ages.

For late VR so 3 pins in triangle.

 

Cheers

Edited June 9, 2012 by GusPW

[daves16v 1]

Anyoneknow the part number for the rad thermoswitch/sender. Can't seem to see it in first post and been searching for ages.

For late VR so 3 pins in triangle.

 

Cheers

 

1H0959481B about £28 from the dealer.

[GusPW 0]

1H0959481B about £28 from the dealer.

 

Cheers, guy on parts desk couldn't find it.

[GusPW 0]

Is it possible to change the rad temp switch without draining and refilling the system?

[nrc 0]

Is it possible to change the rad temp switch without draining and refilling the system?

 

Not really advisable as it's almost at the lowest point of the cooling system and the coolant will just gush out when you remove it. If you want to reuse the coolant then drain from the bottom rad hose into a clean container (10 litre capacity will be enough).

[brunt_star 0]

i am having some really confusing issues with overheating.. the temp gauge seems to work initially, it comes up to the middle and as the car warms up.. but then doesn't rise any higher? the car is definitely overheating.. when i returned from a 20 min drive i could hear the coolant boiling like a kettle and forcing water out of the back of the expansion tank! the fans stayed on when i turned the idnition off as they should.. i checked the aux water pump and this was not working.. i used a multimeter to see if any power was going to the aux pump (ignition on/ignition off) and there was nothing!

I have heard that when the aux pump isn't working correctly then the coolant system can force coolant and burst pipes etc..

Does anyone know;

1.. which sensor is responsible for the temp gauge and why it would work initially and then not rise when i know the car is overheating?

2.. which sensor controls the aux water pump?

 

any help would be greatly appreciated thanks

Edited August 5, 2012 by brunt_star

[Kevin Bacon 5]

1.. which sensor is responsible for the temp gauge and why it would work initially and then not rise when i know the car is overheating?

2.. which sensor controls the aux water pump?

 

 

If you read the thread, the yellow 4 pin sensor runs both of these items.

[Jim Bowen 1]

Not read all the thread, but been reading Dom's bit.

 

My thermostat opens at about 85c, nothing to worry about, but whats this closing bit about? Can't see mine closing or even how its meant to close once its heated up and it seems to be done with a spring that warms up and goes soft.

 

As long as it opens i should be ok shouldn't i?

[robo22sri 10]

It only shuts when the coolant cools, the thermostat is always open once the coolant is up to temp ;) The fans the do the hard work

[Jim Bowen 1]

thats what i was thinking, but the manual and this post says it closes at 105c, which i reckon must be a typo or something

[robo22sri 10]

If it shut at 105c the engine would go bang because the hot coolant wouldn't be able to cool?!?!