My 2001 S4 warms up super slow (water and oil temps) and usually only to the 1/4 marks on both if i let it idle for a few minutes. After any driving it goes back down.
I think this is because the non backflow valve/check valve is stuck open and is allowing the water to continually circulate.
Can anyone confirm? Part numbers or info on where to find the valve would be very appreciated. Thanks in advance guys!