Originally Posted by
dojj
change the temp sensor first to make sure that the guage is reading correctly
if the stat is ok i would check the heater matrix next as if this is blocked it will seem that the car is not getting hot when in fct the pipes aren't doing anything
check the pipes are hot on the bulkhead to and from the matrix
But the fact the heating isn't as the usual temperature coupled to the gauge reading suggests the running temperature to be lower.
Martin