Summer Overheating

My 95 toyota tacoma is only overheating in the summer never seems to overheat in the winter. I put a new thermostat, fan clutch and radiator on in the past year, but it did not seem to help. When I turn the heat on it helps bring the temp. down temporary. Any ideas?

Do you still have the fan shrouds you're supposed to have? Sometimes they get lost when a mechanic works on your truck.

Does it only overheat when your idling, or when you're driving, or anytime?

Check the antifreeze to water concentration...straight antifreeze will not circulate well and can cause cooling problems. Southern states should be 50/50, northern 60/40. You can buy a tester thats like a turkey baister at any auto store for about $10 that will check the concentration. -good luck!