Q: Engine overheating and heat not working. Might need gasket.

When the engine is overheating and the heater does not blow hot the most likely cause is a low coolant level. If all those parts were replaced on your vehicle perhaps important parts were skipped over during the inspection. You may have a coolant leak somewhere such as the water pump, heater hoses, intake manifold, or head gasket. My first recommendation would be to ensure that your coolant level is correct. Make sure not to do this when the engine is hot. This information can be found in your owners manual. If the coolant is low correct this condition and check for any obvious leaks. If there is a leak but it is not obvious to you, have a professional run a cooling system pressure test to find the leak. Once the leak is found have the repair done quickly in order to prevent future engine damage.