The definitive VR6 cooling guide

[avokado 10]

Hi there,

 

can anybody tell me how can i check which fcm should be in my car? I suspect i have fcm problems, so i decided to replace it, just to be sure, as i cannot test it to see if it is bad.

 

I have a 1992 vr6 with aircon (inside climatronic swap, engine bay stock vr6 AC harness). I am affraid that some previous owner might have swaped it for the wrong one...

 

Should i just check if i have the 8 or the 10 pin connector and buy accordingly? Is it a year/model difference for the 8/10 pin connector on the module?

 

Thank you for the help!

[Cressa 44]

Sorry I can't help mate. I have aircon but it is the Diavia fitted version. I think this is going to be a difficult one without having wiring diagrams to compare a climatronic to the manual ones. All the best in sorting as it sounds a great mod.

(Never give up)

Cressa

 

 

 

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[avokado 10]

Actually, as i have checked, the corrado and the passat have the same number FCM (1992 year). But there are several versions of the 4pin + 8 pin FCM.

 

Trial and error maybe?:bonk:

 

edit: Some research pointed out that the 4+8 pin FCM is only one version, later models have different wiring with 4+10 pin FCM (3 different FCM's). VW made an 8 pin to 10 pin adapter for FCM upgrade, but unfortunately it is not availabe anymore. Anyways, the difference is in the wiring (and the later model functionality), supposebly not related to AC.

 

Please correct me if I am wrong, otherwise, hopefully somebody else will find it usefull.

Edited July 21, 2017 by avokado

[avokado 10]

Seems like i can't get 12v to the coolant sensor. I did some digging and found out it is connected to the fuse box inside the car.

 

As it is a total caos in there (full option car), can anybody give me some pointers, where i should check first? Fuses seem ok, but other than that, i am lost...

 

Thanks fot he help!

[graham1971 10]

My VR6 has just had an engine rebuild so I've been paying more attention than usual to the coolant and oil temperatures displayed by the MFA, the car is running beautifully, on a long run yesterday the oil temperature never went over 104, even when pushed hard but the water temperature never seems to go much over 80 which seems on the low side to me, the fans do stay on for a few minutes after engine shutdown but nothing excessive.

Is it indicative of a fault that the water temperature stays so low and as the car is certainly not overheating am I just worrying uneccesarily?:shrug:

[g0ldf1ng3r 15]

My VR6 has just had an engine rebuild so I've been paying more attention than usual to the coolant and oil temperatures displayed by the MFA, the car is running beautifully, on a long run yesterday the oil temperature never went over 104, even when pushed hard but the water temperature never seems to go much over 80 which seems on the low side to me, the fans do stay on for a few minutes after engine shutdown but nothing excessive.

Is it indicative of a fault that the water temperature stays so low and as the car is certainly not overheating am I just worrying uneccesarily?:shrug:

 

do you know if you had the thermostat changed?

 

if not then it is likely it is an old one which gives a more 'true' reading - rather than a new one that VW engineered to sit around 90 constantly

 

the same used to happen on my VR prior to head work & a change of cooling system including stat, the new stat sits around 90 & then rises a7 drops as & when

[graham1971 10]

do you know if you had the thermostat changed?

 

if not then it is likely it is an old one which gives a more 'true' reading - rather than a new one that VW engineered to sit around 90 constantly

 

the same used to happen on my VR prior to head work & a change of cooling system including stat, the new stat sits around 90 & then rises a7 drops as & when

 

Nope, the cooling system had no issues and was left unchanged when they did mine. does that mean something else needs changing then or is this normal?

[fendervg 32]

The thermostat doesn't have anything to do with the the temperature gauge - it doesn't supply it with a signal or anything, this comes from one of the 3 sensors in the thermostat housing, and I don't think the design of those has changed.

 

The thermostat is simply a one way valve that opens at a pre-set temperature to send the coolant round the longer cooling circuit via the radiator once the engine has warmed up. It is possible to get ones that open at lower than standard temperatures - details of those are at the beginning of this thread - but are usually not recommended for standard running conditions. I'd say the tendency of more modern clusters to "normalise" the temperature readings is a function built into the gauges themselves.

[g0ldf1ng3r 15]

Nope, the cooling system had no issues and was left unchanged when they did mine. does that mean something else needs changing then or is this normal?

 

i would say it is normal graham

 

in fact thinking about it my valver has an old stat as that is normally around the 70-80 mark

 

the VR definitely has a 'new' stat & it reads higher

 

your oil temp sounds pretty spot on & a rule of thumb Vince at stealth told me was that water temp is normally about 10 degrees lower than oil temp

 

as such, with your oil at 104, the more true water temp would be around 94 - which is perfectly normal & ok

 

FYI vince also took a digital reading of my VR's oil temp sender, as i was getting some whacky oil readings not long after the stealth work, & the infra red jobbie showed consistently 6 degrees lower than the reading on the dash

 

with your fans also kicking in for a short time after a drive all sounds peachy m8 :D

[g0ldf1ng3r 15]

I'd say the tendency of more modern clusters to "normalise" the temperature readings is a function built into the gauges themselves.

 

i understand your point fender but i would say it is the stat not the gauges as my VR reading changed when the stat did, the instrument cluster is the original

 

IIRC it was Kev Bacon on here that told me that part about VW engineering the stats to sit at 90 to stop their customers worrying

 

either way, id say nothing is wrong graham

[graham1971 10]

Thanks for that everyone, I feel less worried now. My initial concern about the stat fendervg was that the engine may be "overcooling" if the stat was stuck open. I don't know if this even possible but thought it seemed plausible!

 

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[fendervg 32]

Yeah, I'd agree that the temperatures sound normal, so no need to worry. To get a better reading it would be an idea to put VCDS on and look at the coolant temp that is read from the blue ECU sender. I don't really trust the clocks that much. Mine sit between 80-90 degrees coolant, with a lot of variation, and 95-110 degrees oil depending on how hard you are driving.

 

The problem is that there are simply so many parts to the coolant system - radiator, water pump, auxiliary pump, thermostat, fans etc. - that it's hard to pin point something without replacing the lot.

 

I get that VW might have changed the thermostat to regulate the temp by restricting flow to a different base temperature, but I can't see it being that accurate, and I'd say on a VR, once the stat is open it stays open and temperature variations are controlled by radiator airflow and the fans, but I could be wrong.

[seanl82 23]

If the stat is stuck open - which it's designed to do if a failure occurs, you'll see temp rise on the gauge when stationary, and drop whilst cruising. Almost all I've seen sit a touch low, nothing like modern cars which sit steady on 90 all day long. I've changed every part of my cooling system including sensors but except the hoses, and mine still always reads around the 80 mark unless sat in traffic, but provided the fans kick in when they should all is well mate.

[1xshaunx1 27]

Your oil temp is a guide aswell as to weather the cooling system is working properly. Should sit when upto temp after about 10 mins at about 100-110 no matter what traffic or outside temp. If it's not getting there or seeing it go over that there's a good chance something is wrong.

[graham1971 10]

In fairness, the oil temperature seems bang on, having read what everyone has said I'm going to stop worrying about it and just keep an eye on the oil temp. Sounds as though if that's right then all else seems good!

[1xshaunx1 27]

Having said that when sitting @ 4K revs for a good while you could see 120 degrees but water at 90.

[dr_mat 0]

Having said that when sitting @ 4K revs for a good while you could see 120 degrees but water at 90.

Not to mention flashing blue lights in the rear view mirror..

 

 

A Corrado is for life, not just for the MOT.

[graham1971 10]

Not to mention flashing blue lights in the rear view mirror..

 

 

A Corrado is for life, not just for the MOT.

Just take it up to 6K revs for a while and watch the lights get smaller and smaller until eventually they disappear!

Just kidding! A speeding fine and a row is much better than the other possibilities!

[dr_mat 0]

Just take it up to 6K revs for a while and watch the lights get smaller and smaller until eventually they disappear!

Just kidding!

 

Heh, you'd have to be going down a very big hill, or pulling very big power to actually hit 150 mph.. :)

 

 

A Corrado is for life, not just for the MOT.

[Moonlight VR 10]

Hi all,

 

My VR6 radiator fan seems to be coming on very early, after a 5 min run of normal driving . Temp sits around 90 on the coolant gauge and coolant level is fine...any ideas anybody?

 

Thanks in advance

[captainredeye 0]

Would any one have the part number to a 3 stage fan? or possibly check under there bonnet for me, i have just received what i was told is a 3 stage fan from an online supplier but the 4th pin is missing and they aint being to helpful, the fan i bought is a hella 8EW 009 144-541, my old fan is a bosch but the part number has rubbed off.

[captainredeye 0]

Any ideas as to why my second stage isn’t switching on? I have checked the wiring, done the checks and bridged the pins on the plugs 1st and 3rd come on, I have done a current check and I’m getting no voltage when I bridge the terminals for the second stage. Scratching my head here.

[culshaw 1]

Has anyone here blanked off their oil cooler when fitting a mocal? I don't _really_ want to but the kit I've been supplied does this. Therefore I have two options:

 

1. Use a piece of pipe to link the crack pipe back to the block. I'm thinking this

https://www.merlinmotorsport.co.uk/p/samco-8mm-135-degree-blue-hose-elbow-e135-8

 

2. Get an extended bolt for the cap

 

With 1, if you have the knowledge, would a 135deg bridge the two neatly?

 

With 2, if you have the knowledge, have a link to the part you have or bought?

 

I would much rather do option 2 but I can be convinced otherwise!

[fla 9]

Yep i removed my heat exchanger and just used that thermostatic sandwich plate. Make sure you connect the centre bolt the right way round otherwise it blocks the oil flow to the head.

[culshaw 1]

Thanks, I will!

 

What did you use to blank off crack pipe?