I just had the water pump replaced, now less than a week later it is overheating again and sometimes blowing cold air. What does this sound like it would be?
Air in the cooling system, or worse yet, head gasket failure.
Hi so when was the radiator cap last changed as the spring becomes weak over time and the engine appears to boil over.so a new radiator cap usually fixes this problem.
Overheating and blowing cold air --- either a massive air pocket in the system (unlikely after a week) or your thermostat is stuck closed (very likely if it was not done with the water pump). Is your coolant bubbling over in the reservoir when the car is running ?
Unless the weep-hole is leaking on the bottom of the water-pump input shaft housing, the impeller inside the pump rarely goes bad. The impeller is the part inside the water-pump that circulates the coolant thorough the radiator, heater-core and cooling passages of the motor. There are several checks to eliminate possibilities why the cooling system is getting too hot. I wish you had told us the year, make and model of the car plus the number of miles on the odometer. If the coolant has been getting so hot that it bubbles back inside the plastic cooling system reservoir, have a private mechanic do an inexpensive cooling system pressure test to see if you have any external or internal coolant leaks. If not, have the thermostat changed with a factory original. Always check and refill the radiator when the motor is stone cold. Fill the plastic cooling system reservoir 3/4 full when ever you remove the radiator pressure cap. If you or someone has ever mixed chemical types of antifreeze other than the factory recommended brand or type it will eventually plug-up your cooling system and cause it to overheat. It may be necessary to drain, flush and clean the system with a one part acid cleaner. If you haven't in the past had your coolant drained and flushed every three years and your car is 12 years old or older get ready to buy a new radiator. They're easy to install and they're not too expensive these days because they come from Mexico or off-shore suppliers. Keep this in mind: The higher the percentage of antifreeze in the coolant the less efficient the cooling system becomes. Antifreeze is an insulator of heat transfer. That's why race cars don't use it! If this statement is hard to believe, Look up Stewart Water Pumps on the net. They'll tell you that pure water is the best coolant to use for heat transfer purposes. In the real world we can't do that because of temperature fluctuations.
