Audi A4 B8.5 thermostat?

Tiny
KIW
  • MEMBER
  • 2013 AUDI A4
  • 2.0L
  • 4 CYL
  • TURBO
  • 2WD
  • AUTOMATIC
  • 146,000 MILES
Audi A4 B8.5 (2013) 2.0TDI CJCA with CVT transmission.
The engine won't go over 50 - 70c (122 - 140fahren) in -5 celcius and under (23 fahren and under) I understand diesel is much more efficient and produces a lot less waste heat, but I drive 30km every morning and evening with 70% 90km/h
I'm thinking, if the main thermostat isn't stuck open, then it might be the CVT thermostat(which is also connected to the main system) and I've noticed that the CVT tends to slip on hills, lag (the more cold, the more lag) even though I had it checked and the CVT is mechanically fine and I service it every 30 - 40km, what if the CVT is being "overcooled" and causing the low engine heat + slippage?
Friday, January 30th, 2026 AT 1:51 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,877 POSTS
Yep, it sounds like the engine cooling system thermostat is stuck open which can cause the problems you are having. Here is the location of the thermostat so you can change it out, disconnect the battery first and drain the coolant before you begin. Check out the images (below). Please upload an image or a short video in your response
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Saturday, January 31st, 2026 AT 9:38 AM

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