VR6 underheating/over cooled!

[stormseeker 0]

I think my thermostats's gone - under normal driving, the water temp gauge hardly touches 70, but if the engine's left to idle, it gradually creeps up to 100 ish, and the electric fans cut in. If you then dricve off, it gradually makes its way down again!

 

I seem to remember reading somewhere (here or on vwvortex?) that if you're going to replace the thermostat, it's a good idea to replace the housing too - is that right???

 

Also, do I attempt this myself (fairly competent mechanically!) or is it one of those PITA jobs if you've never done it before?

 

Advice welcome,

 

 

Chris.

[Joe M 0]

To me that sounds perfect for the water gauge. What does your oil temp do?

[stormseeker 0]

To me that sounds perfect for the water gauge. What does your oil temp do?

You mean you think the temp gauge in the instrument cluster is knacked?

 

The oil temp rises as the car is driven & stops somewhere between 90ish or higher depending on how "enthusiastically" I'm driving ;-)

 

 

Chris.

[Joe M 0]

My oil normally sits in the 90's once warmed up and only goes above 100 when sitting in traffic, ive never seen it above 108.

I dont think you should worry unless your oil sits below 90 after the cars warmed up.

 

My water gauge sits about 70 and only goes up when in traffic, pretty much the same as yours.

[vr6storm 0]

chris i think you might have a wee problem myself.....as far as i'm aware and i'm sure kevhaywire will confirm too,the vr6 is quite a hot running engine....my water temp guage sits at approx 95-100 on motorway and country road driving and creeps up to 110 sometimes in traffic :shock: ....though to be honest the guage is not that accurate,i had my m8 check the water temp reading with his vag-com and when my guage shows 100 its really 92 degrees and when it reaches 110 its gone up to 97.5 degrees then the fan cuts in and lowers it to approx 92 degrees

also the highest i've seen with my oil-temp(after some hi-speed motorway driving)is 116,normally it gets up to 102-106 around town and as much as 108 if i'm having some fun :wink: .....i use vw's synta-gold fully synthetic oil in mine,but i don't know if that would have any sort of temp effect

anyway i had my thermostat replaced a few months ago,due to the fact that the temp guage was creeping up high,the bottom hose was stone cold while the top one was roasting and when i switched the engine off the cooling fans stayed on while the key was in the ignition

[Scott 0]

I agree with Roddy - I suspect you may have a problem there - sounds like the stat is stuck open possibly?

 

As on a VR6 water temp should get up to 85-90 and stay around 85-95 under normal load driving.... when sitting it in traffic anything up to 110 is normal as the oil dumps its heat into the coolant so the water temps rise. As Roddy rightly points out the guage isnt that accurate anyway as when plugging in VAGCOM it says 100degC is about 95 ish *:) - so its not always running as hot as it may seem.

 

I'd change the stat and whilst at it flush the coolant out and back flush the rad to clear all the dirt out.... but yes would replace the stat housing when doing it as they usually break - if it doesnt you can guarntee it will start leaking *:)

 

An undercooled engine on a VR6 is not a good thing - most VW engines are designed to run quite hot... more important is oil temps though.. I'd want to see 90degC on the oil temp guage within 10 mins from cold start else I'd be worried....

 

Cheers,

 

Scott

[stormseeker 0]

Thanks for all the advice chaps - I think I'll get it booked in for stat & housing change (I've recently been introduced to a couple of VW main dealer mechanics who do a spot of Saturday afternoon moonlighting in their own lock up - but can get genuine parts at trade and charge about a quarter of dealer labour charges!)

 

I'll see if they can get access to vag-com too.

 

Thanks,

 

 

Chris.

[jmk 0]

On the oil temp discussion, it takes between 5-8 minutes (depending upon weather) for my oil gauge to reach 50 (Storm). I commute daily in SW London and before it’s at 50 I only rev to 3k. It's perhaps another 10 mins before it’s at 90 and will often go past 100 (even in winter) during my 9 mile commute.

 

On the motorway at a decent speed it’s not unusual to get near 110, but this is perhaps a little too high so I’m thinking of having an oil cooler fitted this summer. ANyone else had this done - what do you reckon?

[Scott 0]

On the oil temp discussion, it takes between 5-8 minutes (depending upon weather) for my oil gauge to reach 50 (Storm). I commute daily in SW London and before it’s at 50 I only rev to 3k. It's perhaps another 10 mins before it’s at 90 and will often go past 100 (even in winter) during my 9 mile commute.

 

On the motorway at a decent speed it’s not unusual to get near 110, but this is perhaps a little too high so I’m thinking of having an oil cooler fitted this summer. ANyone else had this done - what do you reckon?

 

I wouldnt say 110deg C for oil is too high mate - on a high speed run I can usually see 116degC... Ive seen 126degC in summer in bad traffic... as long as your oil is in goo condition I wouldnt worry about it - a oil cooler is only really beneficial and worth the outlay if running mods I would have thought ?