I had the same problem on my car. turned out to be a blown head gasket.
the no. 1 cylinder was pushing hot gasses into the coolant jacket.
The cap is on the coolant reservoir (driver's side behind the battery), not on the radiator itself as in many other vehicle makes. Mine is yellow. DO NOT remove cap if engine/coolant is hot as system is pressurized.
A broken piston ring can allow oil to get into your cooling system. A bad valve seal can also allow oil into the cooling system.
This might be the cooling fan which in today's cars is electric and runs only when needed, not continuously like the 50's and 60's vehicles. When you sit idling, with no cooling air passing over the engine, the coolant temperature rises and causes the fan to switch on. This could also happen during acceleration.
Josh G makes a good reservoir. So does brock sanderson. <3
Valvoline Zerex.
possibly you need a better grade of gas?
When it is used as a source of water for public or private consumption.
No. Apparently it makes a gel.
The company that makes the all model coolant claims you can.
NO it makes no difference.
Low engine coolant--when you step on the gas water pump runs faster and is calling for more coolant--check level
The water in the reservoir might boil out in your car if your thermostat is not working correctly. You might also be having an issue with your cooling fan.