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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: teamcurtis on April 21, 2019, 10:43:18 pm
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I have replaced this water pump twice now and I keep getting a Heavy, drain all the coolant leak.
Its possible im just not getting a good seal, but I wonder if something else is going on.
The first time the pump went out things were REALLY rusty inside. I had the replace the water neck and thermostat. The neck was rusted alway to almost nothing. I replaced the neck, thermostat, and waterpump and everything seemed to work fine for about a week. Then it started leaking again.
The last time the bong on the radiator for the heater line pulled off as it was rusted clean through. So I replaced the radiator with a 3 row aluminum champion radiator. Its a 19" which seems over sized for a 350. I did not reinstall the fan shroud.
Installing the water pump I cleaned the block really well with a razor blade then brake cleaning fluid. I used water pump gasket sealer on both sides of the gasket and let it cure overnight before filling the radiator.
I used distilled water and antifreeze. 3 to 1, and added some radiator flush to clean out the whole system. Brought it up to temp for about 10 mins and let it cool down. Warmed it up again later that day and let it cool down. No issues. I warmed it up today for about 20 mins and it dumped all the coolant on the driveway. I couldnt really tell where exactly the leak was.
Am I just bad at replacing waterpumps or is something else going on?
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Did you purge all of the air from the system before putting the cap on? Was the thermostat open all the way? Use a pressure tester to check for leaks.
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I know the first time I replaced the pump I left the cap off until it cycled once. I dont think I did the second time.
The thermostat seems to be opening based on the fact that all the hoses were getting hot.
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need to find the leak. could be just from a loose hose
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looks like I'm an idiot and didnt tighten the hose clamp on the return line from the water pump.
i pulled the thermostat housing and cleaned it as it looked really dirty while i was inspecting.
once the gasket sealant cures tomorrow ill refill and see if that was the only problem.
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im sure we all have done that at least once.
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and thats all it was.... all sealed up and runs great.
i do wonder if my thermostat is too high. The gauge reads 3/4 hot before it seems to kick on and quckly drops the temp back to the 1/2 mark
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could be air in the system.
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clean and tighten the connection on your temp sensor.