VW 1.6 TDI: Long Preheat Time Explained

I have a 1986 model with a 1.6 liter diesel engine.
My preheating indicator light turns off after about 1 minute.
I have to pre-heat it for at least 20-30 seconds before it starts without needing to crank it too much.


Has anyone had experience with weaknesses or vulnerabilities (such as corrosion)?

The vulnerability is a broken temperature sensor line.

If the relay does not receive temperature information, it will remain illuminated indefinitely.

You have two temperature sensors, one for the display and one for the heating element.

The cables are white/blue and yellow/red.

Just tap it briefly; once to display the information about "Heiss," and once to immediately stop the heating.

If not, it's probably a broken cable.
If so, a sensor might be broken.

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