Get a combustion leak detector to test for a blown head gasket. These d17 engines are prone to blown head gaskets. Which would explain the overheating and low coolant level in the radiator. I know you said the engine didn’t seem hot, but with an aluminum head, once it gets hot the head warps and is not longer flat, further exacerbating the head gasket problem. If the head is warped you’ll have to get it remachined within Honda spec or buy a remanufactured one. Ask me how i know all of this lol. it can all be done in a weekend so long has a you have good mechanical knowhow, patience, and remain vigilant with things like the timing. If you go down this road it’s worth while to do a water pump and timing belt since that is a “major” maintenance item on higher mileage Hondas. Best of luck!
Get a combustion leak detector to test for a blown head gasket. These d17 engines are prone to blown head gaskets. Which would explain the overheating and low coolant level in the radiator. I know you said the engine didn’t seem hot, but with an aluminum head, once it gets hot the head warps and is not longer flat, further exacerbating the head gasket problem. If the head is warped you’ll have to get it remachined within Honda spec or buy a remanufactured one. Ask me how i know all of this lol. it can all be done in a weekend so long has a you have good mechanical knowhow, patience, and remain vigilant with things like the timing. If you go down this road it’s worth while to do a water pump and timing belt since that is a “major” maintenance item on higher mileage Hondas. Best of luck!