Expert: Brad Sears - 12/17/2008

Question
QUESTION: Our 68 cougar was overheating so I replaced the thermostat and had the radiator rebuilt with a new core. It still overheats and the heater does not get very warm. Could it be that the new thermostat was bad? I don't know what else to check for overheating. thanks.

ANSWER: Ok Jim, I need some answers to a couple of questions so that I can give you the right diagnosis. Does the engine overheat when the car is sitting still and ideling? If you need to drive it to get it to overheat, how far do you need to drive? If it overheats when driving is it speed related, in other words does it get hotter the faster you drive? Let me know.
Brad

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QUESTION: it will overheat when just idling. I just got the new radiator put in and haven't driven it yet and started overheating. thanks for your help.

ANSWER: The water pump and the thermostat come to mind in this case. The lower radiator hose could be collapsing as well. I would check the thermostat to be sure that it is installed correctly. The part of the thermostat that reads the heat needs to go into the engine as the coolant comes out of the engine through the thermostat to the upper hose and radiator. I have also seen water pumps that are older having the impeller blades rotted right off. To check that remove and inspect the water pump.
Good luck, Brad

---------- FOLLOW-UP ----------

QUESTION: Brad, the lower radiator hose appears to be somewhat
collapsed. What can be done to correct/prevent that?
thanks.

Answer
THERE IS SUPPOSED TO BE A SPRING INSIDE THE LOWER HOSE. THE LOWER HOSE IS THE INTAKE SIDE OF THE WATER PUMP. with THE ENGINE RUNNING THERE WILL BE A VACUUM PRESENT THERE THAT WILL COLLAPSE THE HOSE. YOU CAN PROBABLY GET A SPRING AT A HARDWARE STORE THAT WILL FIT INSIDE. IT DOES NOT NEED TO BE A HEAVY SPRING AS THE ONE INSIDE THE HOSES WHEN YOU BY A NEW HOSE ARE LIGHT, BUT JUST ENOUGH TO KEEP THE HOSE FROM COLLAPSING. THERE SPRINGS OCCASIONALLY GET LEFT OUT DURING SERVICE WORK.
BRAD