For every ones information the info I sent to davealfa11 is Alfa Romeos own workshop manual and the opening temp is 80 degrees +/- 2 degrees so from 78 to 82, If you get Alfa Romeo's workshop manual or a copy of the disk from here .:BerlinaSportivo - Alfa Romeo 155 Q4 and Sports Saloons on the net:.
you can check for yourself it is under description and operation! 88 degrees is the running temp i.e. straight up on the gauge (so it looks nice and neat on the dash) NOT the opening temp. You have got to remember that opening is not a switch it is a gradual process, so it opens at 80 degrees and lets a tiny bit of water through, not enough to cool the engine at full chat, not until 88 degrees does the thermostat reach the equilibrium point where it holds the temperature steady.
Now please Davealfa11 would you look it up for yourself you dont have to trust me the link is above and here is how you find it on the disk
So download manual>description and operation>engine unit>second column scroll down to 1088, engine cooling and click on nut type thing at end>end column water pump and thermostat, click on nut thing at end>weird blank page click on nut thing again>thermostat click on books at end and it gives you the opening temp not the operating temp.
The reason Davealfa11 is confused is that in the dim and distant past thermostat manufacturers used to stamp the opening temp on the thermostat, as usual alfa romeo dont do this!
I know that no one is infallible but I did look this one up for you Davealfa11, I have sent you a screen print of the page and a link to an independent site for you to check for yourself, I have copied the link to this page as well so PLEASE LOOK IT UP.