bad water pump?

[tendency]

symptoms: car runs cold on freeway. when idling or in city temp is normal. car blows hot air through heater. sounded like a classic case of bad thermo so i replace the original one and sure enough it was stuck open.

tested replacement thermo before i put it in and opens/closes correctly. now, however, when idling the car it overheats. no hot air is blowing through heater. i squeeze the upper hose and it's very hot however i don't feel a pressure surge.

sure seems like water is not getting circulated..anything that i could be missing? thx-

[Zembonez]

Water pumps almost never fail to stop pumping. When the bushings in them fail they leak, but it's extremely rare for the impeller to fail.

You could have an air pocket in the cooling system.

[tendency]

ok i like hearing that .. so what's the best way to flush out air pockets?

[fenixus]

when engine cools down, open the rad cap and top off coolant mixture up to the lip. close it start it (make sure there is coolant in return tank at at least LOW level), give the upper hose a few firm squeezes with a hand or both. for the time being keep heater at full blast and let it idle until fully warmed up. then try turning heater off and check the temp gauge on dash, if temp still rises than you still have air.

my 5s-fe even after it started properly circulating coolant (no overheating at idle) sucked the whole coolant (was half full up to FULL mark) into radiator over night after flushing.

Not sure which engine you have, but I read that 1mz-fe bleeds air easier when front passenger wheel is off ground (this side jacked up).

[Mister_Perkins]

Originally Posted by Zembonez

Water pumps almost never fail to stop pumping. When the bushings in them fail they leak, but it's extremely rare for the impeller to fail.

You could have an air pocket in the cooling system.

If the bushings fail, it will start to eat the waterpump housing and jam sideways and break your timing belt

[Maim Menu]

^^ Wich happened to me and was super fun, except the pump should be pretty damn noisy before that happens.

[Mister_Perkins]

yeah it will sound almost like a bad motor bearing. lol.

Just be glad you dont have a Jeep Cherokee. Their water pump fins are plastic and like to sheer off so it doesn't circulate and causes the vehicle to overheat with no sounds or noticeable leakage out the pump

[JohnGD]

From your descriptions the water pump appeared to be working before the thermostat. It's not likely it failed while the thermostat was being changed.

What brand of thermostat did you install. Was the jiggle valve at the specified position near the top? Was the thermostat installed in the correct orientation (heat motor towards the engine)? Were you able to add back nearly the amount of coolant you drained? Also, an air pocket can do this to you.

Originally Posted by tendency

symptoms: car runs cold on freeway. when idling or in city temp is normal. car blows hot air through heater. sounded like a classic case of bad thermo so i replace the original one and sure enough it was stuck open.

tested replacement thermo before i put it in and opens/closes correctly. now, however, when idling the car it overheats. no hot air is blowing through heater. i squeeze the upper hose and it's very hot however i don't feel a pressure surge.

sure seems like water is not getting circulated..anything that i could be missing? thx-