Cobalt: NO COOLANT CIRCULATION?

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  #1  
Old 12-31-08, 10:19 PM
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Cobalt: NO COOLANT CIRCULATION?

2005 Chevy Cobalt 2.2 lt eng. 27k miles?, auction car, heater core hoses hot, cold lower rad hose/return from thermostat, changed thermostat, no change in problem. Thinking most likely next to change water pump. Serpentine belt ok, not sure how belt would effect water pump on this motor anyway. Chilton book says special tool to change out pump & have to remove exhaust manifold? Is this the only way to change water pump? Maybe there are other options, beside special tool? Water pump I'm guessing is gear driven? never seen motor like this before, always something new, what will GM come up with next i wonder.......(drained factory antifreeze, & put in ethylene glycol) dex cool makes my heart burn, & eyes red,,,,grin

Thanks for any tips,,,,,,,
Happy New Year! Beer 4U2
 
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  #2  
Old 01-01-09, 09:49 AM
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Did you run the engine from cool to operating temperature, with rad cap off & heater on? Let it cycle 2 or 3 times until the rad fan comes on each time, indicating coolant circulating as it should. Rev engine slightly every once in a while just to aid in flow rate & squeeze out a few more air bubbles. I usually rev it a little & hold that rpm for 30 sec- 1 min, just to make sure any resistance at core is overcome. Sorry, just noticed you said heater hose are hot, in & out, which would indicate to me a blend/air/temperature door problem. Do above as instructed & see what happens first.
 
  #3  
Old 01-01-09, 10:27 AM
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If the thermostat is out try running your waterhose through the rad. hose and see if the water flows through the block.
IF it doesn't someone could of tried to do a auction kwik fix for a leaking head gasket, and it'ss glogged with some kind of stop leak or liquid glass.
IF they put to much in and don't run it long enough to circulate it will stop in one spot and block it up.
If it flows through then that's not the problem.

Was the antifreeze in the car rusty when you bought it? I've seen it rust the fins right off the water pumps.
ON removing the pump try autozone.com and in the how to repair info see if it will help you.
It's free.
Jeff
 
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Old 01-01-09, 12:38 PM
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Drained approx 5qts of 6.8qt system, changed thermostat. Old coolant was mostly clear with a small tint, (pink?), didnt see any part of coolant looking rusty. Put in 4 qts new green, (compatible with all type coolant), and 1 qt distilled water. Left cap off and started engine, as engine heated fluid level in bottle never dropped? 1 heater hose hot, 1 heater hose very hot. At 208deg's, an easy steam was coming from overflow bottle. Upper/return rad hose very hot, lower hose from thermostat cold, no circulation. Passenger compartment gets "mild" heat, (never very hot), only once in 4 months no heat. Just been looking at this problem in last week, son's car. I've never seen the electric rad fan working, prob because rad never gets hot? I'll try to get it to a radiator shop when they open on Friday, and see what their diagnosis might be. Water pump makes no noise or visable leaks.
Thanks,
 
  #5  
Old 01-02-09, 12:23 AM
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The fan sensor is on the block, turn the AC on that will turn on the fan.
If it doesn't that's another thing you need to fix.That might be temp sensor for fan.But with AC on it should bypass that sensor.

On the water pump the "spinner???" could have came off.Still curious if water would flow through the block.
Jeff
 
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