hi how are you, I have a 1992 Chevy Corvette. Recently they had to do a head job because of a blown head gasket. However the car still running hot between 230 and 270 degrees. I noticed that the orange coolant had been replaced by the green one and water 50/50. Could that be of the high temperatures ?

Your coolant system may not have been purged properly. You might have an air pocket in the system. Check the inlet duct for a build up of trash,leaves,etc

When they did the work, did they do a flush on your coolant system? Check and see if there is enough coolant in the over flow before starting it. The green stuff is just fine and the prop;er mix. If your in North Dakota or Canada, in the winter time you may need to up the anti freeze in the winter. You may have a sticking thermostat. If they check it, have them put in a new one, it is a lot less expensive than a new engine.

Like GRT90 said...check the cooling air intake for trash/blockage. C4 ('84 to '96) Corvettes take their cooling air in from underneath the front bumper. They are "bottom breathers". They act a lot like a vacuum cleaner going down the road. Over time they'll suck up all kinds of things....leaves, candy wrappers, coffee lids, etc, and if not cleaned out once in a while will build up in front of the radiator and reduce the amount of cooling air that can get through the radiator. C4 Vettes run pretty warm to begin with....restrict the cooling intake airflow and it'll quickly get a lot warmer. It's a two or three hour job, give or take, to pull the radiator shrouds off and clean out the junk. (They make an after-market screen device that you can add over the cooling air intake to significantly reduce this if you find it's a major problem where you drive).