Car Running warm - Help!

[easto]

Advice needed guys...

since the weather had warmed up the car is running upto 105c so far.
Ive had the car over 2 years and it usually sits on 90c.

Ive had a quick search round and most issues are with it not reaching 90c and it potentially being the sensor.
I'm not loosing any water and am wondering if its
1/ thermostat
2/ Sensor
3/ Fans not working (what temp should the fans kick in at when sat in traffic?)

I dont have alternative transport so am worried about running it

[tdiquattro]

if the thermostat is stuck closed the rad will be cold / luke warm - but they normally fail stuck open.

if the fans arent running it is more likely to be the fan control module, about £100 for a replacement plus fitting - it switches the fans one at 2 speeds, fast and full speed at 2 different temps, something like 87 and 102 (measured at the rad)

first you should change the temp sender anyway, they are so cheap and easy to get to just under the hose from the airbox to the engine get the sender , o-ring and a new plastic clip and change it, but it probably wont help as they usually read low when duff.

[neckarsulm]

Your water pump impeller may have broken, when was it last changed?

[Virdee Autos]

From my experience if the impeller frees off, then the car will overheat in literally no time after it hits 90.

Try the sensor first - cheapest and easiest option!

[neckarsulm]

From my experience if the impeller frees off, then the car will overheat in literally no time after it hits 90.

Fair point but I've seen them with blades missing rather than complete failure of the impeller which could reduce coolant flow - but as Virdee says cheapest option first..

[easto]

thanks for all the responses guys - Ive just been outside to fire her up and see how quick it comes up to 90 and observe if the fans come on...

Lo and behold I have just noticed that as soon as the Key is turned the Temp guage and oil guage needles flick right upto what I would consider 'normal' operating temps. Oil at just over the first readout and the temp guage straight upto 90c........

Apols as this is the first time I have noticed - I guess I have caused a wild goosechase - BUT Im hoping that this indicates it something les serious.
For info - I have recently had the DIS refurbed...

[easto]

Update on problem that might give someone a few clues to set my mind at ease for the moment...OR not!!

got home from work... car is sat fairly comfortably at 105 line.
Got out - both fans are on.
Silver radiator is very hot...black one in front of that is cold (not even sure what that one is for!!)

If the thermostat was shut - would the silver rad be warm... or is it the black rad that should be?

New sender ordered anyway!

[Virdee Autos]

Black one in front is the A/C condensor....so this wouldn't get that hot, especially if you wasn't using the A/C.

Silver one will be hot as this is the engine radiator. But this will get hot no doubt, so regardless whether the gauge is showing incorrect or not, this will have been hot.

[imolas4uk]

you need to check the actual values in the measured blocks of the dash and engine with vag com check coolant temp values against the analouge gauge on the dash,perform an output test of the analouge clocks in the dash all needles should rest in the centre,i suspect if somone has had your dash in bits and when you switch the ignition on the needles jump up your fault maybe there.

[easto]

Just an update -
Bought Green Temp sensor of fleabay.
Started removing intake hose and noticed that the one in the car was Green. Despair! Carried on regardless as no harm changing it and it could still be that at fault.
And it seems like it was.... Very fiddley and some 30 huffing and puffing later all done.

From posts Ive read on this the guage normally under reads - mine was starting at 90 as soon as the key was turned and moving round from there. And green ones degrade also I guess. Not sure how long that one had been in the car (It came out quite easily)

Thanks for posts.

[rickoshea]

So, did changing the sensor fix it ?!

[R12]

I find it strange that both needles, oil and water, would shoot to normal as soon as the car is switched on after it sat all night. Is this still the case? Should only behave in such fashion if you've been driving, shut off and within a short while start it up again.

Would be interested to know your findings.

[easto]

Yes sorry - it did fix it.
Its absolutely fine. Since changing the sensor the needles both rise gradually as what i would consider normal in these conditions.

Strange as it was the oil needle would rise...but then drop almost immediately to zero. whereas the temp would stay sat at 90.
It would have done this after 2 days standing.