Could really use some help. Recently replaced a bad water pump (including serpentine and radiator hoses) to the 1988 V8 305 TBI firebird. Didn’t have this issue before but now when I pour fresh new coolant in the radiator, it completely pours out from underneath the vehicle. I can’t find the leak but it seems to be seeping out from bolts underneath the vehicle. I’ve ran out of ideas of what it could be. Would love some recommendations, advice, or help.

 

Where does the coolant come from? Get a light and shine it into your engine bay so you can see what's going on. Maybe take a video of it while it's leaking.

 

It sounds like the gasket shifted when you put the pump on. Look to see if the coolant is coming out just below the pump. If so, remove the pump and put a new gasket on.

 

Also check the mating surface where the pump bolts to the block. I installed a water pump on my '92 that was the exact same model/part number/manufacturer that I had on my '91. Somehow, on my '92 the water pump was making contact with the accessory bracket ever so slightly. Nothing significant, but just enough to keep the pump from seating properly until I filed it down to fit.

 

Radiator petcock still open?

 

First thing to do is, identify where it "pours out" from.

That's my "idea".

Then fix it.

More than likely, it's something you did or disturbed or forgot or that just didn't work right, in your WP job. Go back and look carefully at EVERY piece you touched.