Thermostat related issue

[LowLife_Mk4]

Hi guys I have a jetta 4 tdi. For a while now I noticed the heat gauge does not stay at 90 (centre) after its warmed up.it does not pass centre but drops and at tyms back to 90 again . I know my fair share on cars but theres always room to learn more.

Is this normal or not
Thankz in advance for ur input

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[Pynoxim]

Yeah that's thermostat related. Replace it, at least it's super easy and accessible on your car.

[Lloyd09]

Yip, Thermostat. its probably stuck opened, You'll also notice that your heater isnt blowing out hot air aswell.....Had this issue on my Bmw. It's best to have it replaced.

[kyle12]

I had the same issue. Took thermostat out. Put it in some boiling water. It seemed fine, opened and closed but I still replaced it and the problem was solved.

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[LowLife_Mk4]

Thanks guys ordered it and will replace it soon

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[LowLife_Mk4]

Just replaced my thermostat today. The temp is sitting at 90 but dropping very slightly at times. Like to 88 or Soo. It that normal ?

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[Jueshen]

could also be coolant temp sensor i usually change thermo and sensor together...

[panic-mechanic]

of course temp changes . Honestly don't worry about small changes like that. It's a dynamic system , climbs and drops the whole time.