Cooling System New But Not Flowing

Keith5.0GT

Active Member
May 29, 2017
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Well....1990 gt with new aluminum radiator, timing cover, timing chain, water pump(stock reverse flow), and all new hoses. And I’m not getting coolant flowing through upper radiator hose, even if I remove thermostat. Flowed before new parts. I started her up finally and after warm up it got warmer than normal so I know something isn’t right. So can a brand new water pump be defective? I really don’t know what to do. But it’s been weeks and I want to drive it. Thanks for any ideas.
 
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Make sure you run water through the engine just to make sure there is no restrictions in the passages
Well I have the water pump off. It seems to be in working order the best I can tell. If I pour coolant in t-stat housing with the t-stat still in, coolant steadily drips from right timing cover coolant port but none from left. Not sure if it should come from both sides or not....any idea?
 
Well I have the water pump off. It seems to be in working order the best I can tell. If I pour coolant in t-stat housing with the t-stat still in, coolant steadily drips from right timing cover coolant port but none from left. Not sure if it should come from both sides or not....any idea?

Can there be so much air in the system that the coolant won’t flow to upper radiator hose?
 
Alrighty, update.
Took t-stat out and rand water through engine, came out both ports in timing cover....so I can’t find a problem with anything. Only theory is way too much air in system. I filled coolant via the t-stat housing and with no t-stat yet, coolant seems to be flowing. I’ll put it back right and give it the true test. Everything works so it has to work. I hope.
 
Alrighty, so just to update...when I had everything apart, I checked it all and it all seemed functional. So I put it back together and filled coolant through the t-stat housing, under the assumption that the only thing it could be was a bunch of air trapped, not allowing circulation. And it seems to be working now. So all that trouble was apparently for some air. I redid lower intake gasket at the same time so I guess that allowed even more air in. But thanks for the replies everyone. I appreciate it, as always.
 
Just wanted to update Incase it helps anyone in the future.....after all the new parts, I haven’t seen coolant flow from or to the overflow tank. And if I take the radiator cap off when it’s completely cold, I get a surge of pressure release. So I put the old cap back on and drove it. Overflow tank is empty and system is not pressurized in the morning....so all that trouble may have been from a brand new defective radiator cap. This year I’ve got a defective overflow tank, defective egr sensor, defective speedo cable(too long) and now this. Really pissed that I order new stuff from lmr and it’s not as good as the “old” stuff I take off.