overheating.it has a new thermostat,radiator is clean.temp stays normal during idle,rises when i start to drive.ac is off when this happens.its a 4.7 dodge durango.can water pump simplyquot;go badquot;without ever leaking?
The short answer to your question: It is unlikely that a water pump will go bad without leaking, but weirder things have happened. Your thinking is right overheating only when you drive is an indication of limited flow, either caused by a restriction (radiator, hose, thermostat), an air bubble, or a bad pump. Are you sure that the air is bled out of your system? If you have an air pocket in your engine or at the pump, you will get reduced flow. I think that the 4.7 Durango has a radiator cap, if so, with the engine cold, take the cap off, fill it, and start the engine. If you get bubbles every time you rev the engine, then you may have a bad head gasket, this would introduce bubbles in the system... Make sure that the lower radiator hose is not collapsing. Most of these hoses have a stiff spring inside to keep them from collapsing when the water pump is running. Otherwise, my guess would be that your pump is bad, or you have more restrictions in your system. Good luck.
if it,s circulating then the water pump is doing its job. does the fan kick on? maybe 1 of the hoses is closing up when your driving. usually when the bearing goes bad in the pump it takes the seal out too and starts to leak.
