Radiator Issue?

Do you have an oil pressure gauge, if so does it work? If all your gauges don’t work it could likely be an instrument voltage regulator (IVR).

The easy way out is to buy an aftermarket temp gauge & mount it under the dash. You can buy electric ones where the sender goes in the hole for the original temp sender. You can also get a mechanical one that goes in the top radiator hose. I have the one in the radiator hose and it works good and is easy to install.