Coolant Temperature/Thermostat

[eptesicus]

Hi

I am wondering if i may have a stuck/partially stuck open thermostat. The car is a petrol 2006 VRS and on my way to work there is a long mile + steep downhill stretch where i just coast in gear and off throttle the whole way. During this time, the temp gauge shifts slightly from the centre but goes straight back up again within seconds of comeing on throttle again.

The car never takes longer than 10 minutes to warm up ( for the temp to reach the centre of the dash gauge) and sometimes will warm up sooner if i am on the throttle more e.t.c. The gauge needle is always at the 12 O'clock mark apart from this long downhill/coasting in gear stretch.

I have used the climatronic setting 19-2 to monitor the engine coolant temperature and it fluctuates between 76-82 depending on what i am doing. On the downhill stretch it will drop to 71 and i notice the dash gauge needle moves below 75 degrees (as shown on the climatronic). Is 76-82 for the normal operating temperature too low? I would have thought the temp would be more like 85-90?

I keep getting mixed opinions all over the web and other forums. Some people say yes, the stat is dodgy, others say it is totally normal for the engine to cool when coasting in gear for a long period of time because the injectors shut off and only momentum is turning the engine.

I know its 2-3 hours labour + £30 odd for the stat housing so i dont want to spend £200+ for no reason.

Do any of you guys with Mk2 VRS's know what your temp yours runs at? I would be hugely grateful if you could test it next time you are out in the car as well so i can get a consensus of what the correct operating temperature is.

Thanks

JT

[eptesicus]

Anyone? I may be worrying over nothing but it would be nice to get some other temps from other peoples VRS's.

[Metblackrat]

Coasting downhill in fear uses very little, if any at all, fuel. To get heat you need combustion. No combustion, no heat. Add in the air cooling at this time of year and there's a possible answer for you.

[eptesicus]

Just bumping this in case anyone else can offer any input? I would just like to know what other peoples 2.0TFSI are showing for their coolant temperature in the climatronic display.

[gsp]

Not had this on a Skoda, but on my last car when the coolant Electro mechanical valve between the engine and the radiator failed.

Its failure state is often fully open (I guess for safety to prevent overheating), so the engine over cools. Older cars this was purely mechanical, but newer cars it is electronically controlled to keep a very stable temp.

Suspect this is your issue as shouldn't normally get this behaviour.

[zei20t]

ive been monitoring my coolant temps over the last few weeks with the polar fis+. they sit around 90-105 in traffic and when im being less nice, and around the 90 mark. mind you, this is a CCZA TSI motor, but AFAIK most newer engines run hot for cleaner burns and emission reasons.

can you remove the thermostat yourself and stick it in a pot of cold water and put it on to boil? it should open up as the temperature rises.

[eptesicus]

ive been monitoring my coolant temps over the last few weeks with the polar fis+. they sit around 90-105 in traffic and when im being less nice, and around the 90 mark. mind you, this is a CCZA TSI motor, but AFAIK most newer engines run hot for cleaner burns and emission reasons.

can you remove the thermostat yourself and stick it in a pot of cold water and put it on to boil? it should open up as the temperature rises.

Hm interesting. Does your climatronic reading give the same results? I can't take it out, and if i could so easily i would just change it. The part is only about £30! Ive read you have to take the alternator off to get to it and that it can be a ball ache of a job.

[Hairy Chris]

Sounds pretty normal to me.

When coasting in gear no fuel is used therefore no heat being produced, combine this with a cold ambient temperature and the fact that the coolant is still circulating and loosing heat through the heater the temperature has got to drop.

[eptesicus]

Sounds pretty normal to me.

When coasting in gear no fuel is used therefore no heat being produced, combine this with a cold ambient temperature and the fact that the coolant is still circulating and loosing heat through the heater the temperature has got to drop.

This is what i thought. I just though 75-80 degrees was a bit low, operating temperature wise but maybe not. Does anyone know what the thermostat is rated at in the 2.0TFSI engine? I have read mixed reports. Some say 80, some say 87. If it was 80 then my temps are probably normal.

I took it on the motorway last weekend in temps of 1/2 degrees and at a steady 70 the temp on the cimatronic was 79 degrees.

[zei20t]

my climatronic doesn't show coolant temperature, all I know is the factory gauge is heavily padded.