I have a 2001 MK1 1.6 Zetec Focus (Zetec-SE/Sigma engine).

My old mk4 fiesta (1.25 zetec) used to run @ around 90c coolant temperature.However the focus runs with coolant temperature normally @ around 100c - highest I have seen is 104c.

The coolant temp needle on the dash stays in the middle but I know it always does this and just jumps to red if overheating.

Is 100c too hot?

P.S I'm getting the coolant temperature via OBD.

100 degrees is perfectly acceptable, however, if the car hasnt had a flush and new coolant, then it would do better if you got it renewed.

This would at least allow it a better chance to cool down the engine and bring that temperature down a little.

Coolant flush done.

Still about the same so far, maybe just 1 or 2c less. I will keep an eye on it over next few days.

I may enable the test/diagnostics mode and check the temps on there, is it ok to leave it in diagnostics mode for a 20 minute drive?

Though the dash shows 90 the actual thermostat doesnt open fully till about 95 degrees so 100 is normal most cars run at 100 degrees or more to improve emissions so youre worrying about nothing no matter what any cars gauge says it will never run at 99 degrees always more than that

You'd be able to run diagnostic mode all s

Day If you wanted to

Sent from my MY SAGA C2 using Ford OC mobile app

Nice to know,

I will stop worrying about it.

I did have a head gasket blow on an older car so just slightly paranoid.

Gaskets dont tend to go on the focus so i wouldnt worry too much if it was running hot the fan would be running constantly