1971 Pontiac Radiator Overflow

I have a 1971 Pontiac. Once last year and again today, I took the car to a show in very hot (90 degrees) weather. In putting the car back into the garage, I noted that anti-freeze coolant was coming out of the overflow hose on the radiator. Unlike newer cars, there is no reservor on this car so the coolant comes out of the hose and onto the ground. When the car cools, the flow stops. The car wasn't running hot (the "hot" light did not come on). This doesn't happen in cooler weather. Would it help to change the radiator cap or is this normal because of the hot weather? Thank you for any information. This kind of behavior can be considered normal and it is the reason modern cars all have overflow reservoirs. You may or may not have anything wrong with your cooling system. If the temperature gauge reads normal, you likely have nothing to worry about even if there is a repeat overflow on another very hot day.

BTW, you can always add on a coolant reservoir. Kits are available. At least you don't have to worry about finding underhood space for it! Thank you. Hopefully, there is no problem. This happened last year on a day where it was very hot and I had driven a slightly longer distance. The car only has a light rather than a gauge, but it was not reading "hot" and I know that light works. You might consider installing a temperature gauge as well as an overflow reservoir. They are inexpensive and very, very useful to have around. There are good reasons too why all modern cars have abandoned the light for the gauge.