Should the coolant temp gauge stay at 90c on 2.0TDI B8.5?
- Thread starter sat1983
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Should stay at 90 but if the stat was failing it would be the opposite.Wait and see if it worsens or if there are other symptoms of a problem eg slow to warm up or poor heater
This is usually* a symptom of the thermostat sticking open, has happened on every one of my cars bar the current one lol
If it worsens and drops regularly get the thermostat and temp sensor replaced, they are cheap parts to easily rule out
If it worsens and drops regularly get the thermostat and temp sensor replaced, they are cheap parts to easily rule out
agree if it was fully stuck open, but worth considering it is 'sticking' rather than broken entirely.
My A4 was like this for months, only occasionally I would notice it, then eventually it got worse and got stuck for good.
My A4 was like this for months, only occasionally I would notice it, then eventually it got worse and got stuck for good.
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I've just recently changed the thermostat on our 2.0tdi, it never got to 90 since we got it 3 years ago unless you were pushing the engine, it also seemed to start to run even cooler as time went on. It's now spot on and rises to 90 and stays there no matter what your driving style is.
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A genuine CTS isn't that cheap and if its only off a bit and no other problems I would leave it for a while at least.A scan would show if its the CTS and it wouldn't run well.Stats are still basically simple and are meant to fail fully open which gives poor heater and slow warm up dropping back at speed.I would always change one if it seems to be acting strangely but unfortunately its not that easy on many modern cars.I think it would be worth checking that the fan isn't running when it shouldn't.This would show more at lower speeds
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Car is 5 years old every chance it's the thermostat. Most cars these days have electronic temperature gauges that are really just for indication. Even my 2002 TT works the same. If the engine temp is anywhere between about 78 degrees and 102 degrees it will show 90. That's why on nearly all modern cars it sits at 90 when warmed up. It just means that the engine is at a normal running temperature. If the stat is sticking open then the engine temp will drop below the 78 degrees so the temp gauge will drop. The engine will also take longer to warm up.On a motorway or dual carriageway at speed the engine is working harder so although there is cooling taking place it will not drop below 78 degrees.
Get it sorted it's costing you fuel as the car is taking longer to get to running temp and it won't get any better.
Get it sorted it's costing you fuel as the car is taking longer to get to running temp and it won't get any better.
Slow to warm up is a sign of stat failure but if yours gets to 90 at speed you should have plenty of heat if it stays there.Still think it maybe the fan.Have changed lots of stats cos they wouldn't hold 90 at speed and were slow to warm up.Some diesels are slower than petrols to warm up but my 2,5tdi B6 is quick.Wouldn't like to change the stat on that .
Yeah past month or so taking longer to warm up but 90% of the time it's at 90 unless stationary with heating up high.
Al get round to changing it.
