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Q: Car has a coolant leak

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My car recently developed a small coolant leak. It was near the area of the water pump, so I suspected the gasket. I didn't have time to fix the car, so I added a can of Barr's liquid aluminum stop leak. That helped for a few days, but then my son was driving the car and it started overheating. Turns out that there was a crack in the larger coolant elbow, which was spraying coolant up onto the top side of the hood. We replaced the elbows with aluminum ones, replaced the water pump and gasket, refilled it with coolant, and then drove around block. But after all of that, the car is still overheating all the way to the redline, and then the warning light coming on. We then replaced the thermostat and it still overheats. At this point my suspects are: A. air in system B. radiator clogged. C. heater core plugged (aka: is the coolant flow to the heater core in series or parallel with the coolant flow to the block?). D. blown head gasket. Any suggestions?

A: If you did not bleed the cooling system aft...

If you did not bleed the cooling system after performing the repair, there is probably air in the system. Air can be bled by running the engine with radiator cap removed and a special funnel installed, or by using a vacuum fill tool. If you properly bleed the system and the problem continues, it’s likely that the engine was damaged from overheating and/or the Bar’s Leak has clogged the cooling system. I suggest you have a trained professional diagnose your vehicle firsthand to find culprit of your overheating issue.

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