110 overheating after ford

My mates '83 110 has decided to keep overheating ever since getting stuck in a ford/big muddy puddle. When we got it back the belt had slipped, which was also causing the alternator warning light to come up!

Ive not seen it since, but he's replaced the belt and got it running, but said he ran it round the block and the temp gauge went into the red?

To me, a 2.25 diesel ran for that short of a distance has no reason to overheat - anyone else agree?

I'm going to suggest draining down the system and replacing the probably ancient coolant - any other suggestions, does it sound at all serious? If/when I get up there I'll start feeling hoses etc to see what's going on. Just wondered if anyone had similar problems before. Cheers

is it actually getting that hot or is the gauge just saying it is? could be a bad earth backfeeding through the gauge

It it is genuinely overheating have you checked that it isn't just the radiator being completely blocked?

Depending on how much mud/sluge/crap there was in the puddle and how much of it may have got into the radiator it could be that it has no cooling ability at all.
I had this once after a pay & play day, I barely got a mile down the road before the temperature gauge went right up, luckily I always carried a decent quantity of water when playing and there was sufficient to alow me to clear a decent patch in the fins which in turn allowed me to get to a hosepipe and complete the job.

Sorted it today - at first we thought the water pump wasn't being driven due to the fanbelt slipping, but then realised there wasn't enough coolant to actually open the stat...topped it up and it opened straight up, all sorted