winter engine temp raise slowly in my case? T-stat stuck at open?

[han95]

Hi all, I am VW's fan. 2007 passat B6 diesel 130k mileage. Every morning in winter, same driving route.
the outside temperature is 0 degree centigrade (32F).


I have to drive 2.2 miles and 10min and then the gauge start to move from the bottom.
And then continue to drive on motorway up to 12miles and 20min. The gauge reach the 90 degree centigrade (190F). At the moment, if I turn on the heater fan in the car, the temp will drop to 80C. Until driving more 10 min. , the final temp reach 90C(190F)


I feel the coolant temp raise too slowly. If I compare with my golf 2010 MK6 diesel.
All of condition are same. But only after 1.5 miles and 5min, the gauge start to move from the bottom. and then 3.5miles and 7min driving on motorway, gauge can raise to 90 degree centigrade (190F).


do you think that thermostat of my passat B6 stuck at open status?

[RichardSEL]

Yes, because your temp gauge falls when you switch on heater.
Thermostat change. Flush out old coolant. Back flush if possible.
Fill with fresh G12, G12+, or G13 50% diluted with boiled water (to get some of the chalk out)
Or better use de-ionised water.

[niall campbell]

or buy it pre mixed , even better

he has the same thread going in golf forum

[RichardSEL]

I didn't know that the VW spec anti-freeze could be bought pre-mixed?
Is that to 50/50?

[niall campbell]

I use Triple QX Red anti freeze from euro car parts

you have the option of buying concentrated or ready mixed

if you go in with the specs you need, you can check it out, I am sure Halfords must have it on the shelf

[jjsf20]

My mk4 golf does this ever since coolant flush but its more that after its reached 90'.. While driving the temp drops. Could it be the temp sender too? And is this a common after a coolant flush?

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