It appears like two unrelated events happened at the same time.
So dont try to co-relate them. Just concentrate on the overheating part.
i.e. coolant, coolant/water ratio, air in the coolant system, thermostat, temp sending switch(or its connector if any) etc.

On my 85 300DT temp needle jumped for a few days after the coolant and thermostat was changed. It was bleeding the air bubbles out itself during this time. Now the Needle is steady.

MVK

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One penny saved is three penny earned.

1985 300D Turbo 179,000miles