Audi 80 B4 TDI: Coolant Temperature Issues

Hello!
Last week, I bought an Audi 80 B4 TDI (90 hp, 1.9l engine). And now I'm starting to gather my first experiences with a diesel car.

'Approximately how long does it take for the coolant to reach operating temperature in a diesel engine? I understand that it takes longer than in a gasoline engine, but is it normal for it to take around 8 kilometers at 80 km/h in fifth gear?'

What is the normal operating temperature for the coolant? I've always assumed it was 90°C, but it never quite reaches that. The gauge needle always stops about 3mm before the 90°C mark.

Best regards, Daniel.

Okay, I have the same car, and you won't be pushing it hard on those 8 kilometers. My gauge never goes up to 90° either. I had to replace mine about two years ago because it wasn't reaching 70°. The car doesn't have an auxiliary heater (like a glow plug) in the water system yet.

Best regards,

thomas

I have the same car, and it behaves exactly the same way.
I find it quite annoying, especially in the winter, how long it takes for it to warm up.
Perhaps it's possible to retrofit an electric auxiliary heater?