Here are 10 tips to address with any overheating problem:
1. Many cars overheat from more than one problem. Often we assume a bigger radiator or a similar big gun solution will fix our problem. Maybe it will, but often by so doing you are addressing the symptom and not the cause. Many cars over the years pick up little annoyances that contribute to overheating. Individually none of them would overheat your car. Collectively you have an overheating problem. Look at the whole car when addressing overheating problems.
2. Before you do anything else, tune up the car. Many overheating cars are out of tune, Be dead nuts certain you are not running lean or with retarded timing.
A lean fuel mixture will overheat your car right now. If your engine runs lean you can chase your tail looking for problems in the cooling system and never figure it out. Be sure you are not running lean. The easy way to do this is richen your jetting a couple of steps. If the overheating is better, you're on the right track.
3. There is a lot of misinformation about ignition timing and cooling. Retarded timing contributes to overheating. Advanced timing helps cooling. Bump up your initial timing a few degrees and see if it helps the car run cooler. It's an easy and practical fix. Of course, if you advance enough to enter pre-ignition or detonation you will start to overheat. Detonation contributes to overheating. If you start to detonate back off the timing. Overheating cars should always run vacuum advance. Vacuum advance helps cooling.
4. Cars can overheat from coolant circulation that is either too slow or too fast. When your car left the factory it probably had the correct speed for the water pump. Over the years things change, pulleys are swapped, rear end ratios are changed, tire sizes vary. Your car may not have the right circulation speed for the water pump. Remember cars can overheat from circulation that is either too fast or too slow.
5. Look at your airflow. Be sure your shroud fits properly and is sealed to the radiator. What'd ya mean you don't have a fan shroud??!!?? If not, obtain a shroud before you do anything else. You can adapt a shroud from the junkyard or many after market suppliers can provide you one. Seal the shroud to the radiator with weather stripping.
6. The best all around fan is the factory design with a thermal fan clutch. Flex fans aren't as versatile, Solid fans pull lots of air but are noisy and suck horsepower when you don't need the extra cooling.
If you need extra air flow there are many electric fans on the market that can help. Be sure your charging system is up to the task of handling the extras amps from an electric fan.
7. Reduce the antifreeze in your coolant. A 50/50 mixture does not help cooling. Either run 100% distilled water with water pump lubricant or distilled water with about 15-20 % antifreeze. Either mixture will cool better than 50/50 and still lubricate the water pump and provide corrosion protection for your system. Remember when the weather turns cool to switch back to 50/50.
8. Use a better grade of gas. If you are not running premium and you are overheating, step up to the top grade. If there is no improvement, try advancing your timing a few degrees. The extra octane will allow you a little extra timing without getting into detonation. Many older cars and particular muscle cars were designed for better gas (4 or 5 star, > 98 octane) than is now available. If you are detonating on today's gas you can be overheating. Remember not all detonation is audible.
9. If you are running an automatic, install a quality after market transmission cooler. Cooling the transmission is added work for an already overtaxed radiator. Do not mount the cooler in front of the radiator where it will overheat the cooling air. Rather mount it to one side.
10. Notice your driving habits. The more gas you burn the more heat the engine produces. Jackrabbit starts followed by hard braking, constant acceleration, flogging the engine uphill, all burn lots of gas. Yes, these are performance cars and that's why we love them. We're not saying don't enjoy your car, but if you are constantly into the accelerator, you are producing extra heat that the cooling system has to get rid of.
Compared to the expense of buying parts in a hit and miss fashion to solve your problem, investing in researching the origin of the issue is a downright good investment.
(text based on information from various sources on the internet)