just got s max part ex focus. the focus warmed up quickley but the s max seems to take a long time.

Is this normal?

It can be, some deisels take ages to warm up, especially in cold weather

My morning commute in my Mondeo was 3 miles, it could take 5 miles to warm up (depending on weather, how hard i drive/ whether i used the cabin heater) -  

The other thing is the AC can come on (automatically) on defrost, this can put the radiator fan on automatically

It turned out there was an electric water heater in the feed to the cabin heater that had burst, even with it working it took a while to warm up in cold weather with the cabin heater on. - overcooling was a problem

Eventually i fitted an electric water pump (electronically controlled) that does not come on at all untill the engine is warmed up, and it warms up quicker , it also reduses parasitic loads to help perfornmance/ economy     

Check your coolant level.

IF it's down - you have a leak & need to get it sorted before your engine overheats.

Quite a common s-max issue.