Got a 87 Coupe GT

[Colin Fiedler]

My friend gave me his 87 Coupe GT because he didn't need it, all in all it
is in great shape and runs well, but I need to figure out a problem it is
having.  After running for a few minutes the temp gauge spikes and stays
hot.  The oil temp is normal, there is no coolant boiling or anything, so it
is not actaully overheating.  What can I check to see what is wrong?
Thanks,
Colin
87 Coupe GT
88 323 GTX
90 Miata