Hey y’all

I’m starting this new thread to see if anybody can help point me in the right direction on diagnosing this problem.

What I know: engine temp keeps going up and up and the fan never turns on.
The fan will turn on a slow speed when the AC is on.

There is no cel light or codes

That’s all I know

Any ideas or tips?

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Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"