Coolant leak

[Joe_with_the_Lumina]

So guys I have had a minor coolant leak but today it got really bad I filled up the radiator and overfill tank then drove around for about 30 minutes all that time there was coolant dripping leaving huge puddles in the places where I stopped I parked it and turned it off and there was a hiss near the thermostat and coolant leaking off the bottom of the car seeming like it was comming from the back of the engine there is also NO indication of oil and coolant mixing. Do you Guys have any ideas?

GM 3.1 V-6 58,000 miles

[Nas Escobar]

I would let it cool down then do a radiator pressure test to see where your leaks are coming from. The reason the engine has to be cold is so you can touch around the engine and look closer without worries of getting burned.

 

However, I would suspect the hoses and not the block itself.

[rich_e777]

So guys I have had a minor coolant leak but today it got really bad I filled up the radiator and overfill tank then drove around for about 30 minutes all that time there was coolant dripping leaving huge puddles in the places where I stopped I parked it and turned it off and there was a hiss near the thermostat and coolant leaking off the bottom of the car seeming like it was comming from the back of the engine there is also NO indication of oil and coolant mixing. Do you Guys have any ideas?

GM 3.1 V-6 58,000 miles

 

Back of engine? I would suspect heater hose first at the quick disconnects but would also follow the source of the hissing sound. Did that model come with a coolant branch off going through the bottom of the throttle body? Common coolant leak area as well and would drop on top of the exhaust cross over making the hiss. A pressure test is a good way to find the leaks and you can rent the tool from most auto part stores or sometimes if you do it in the parking lot which you can its simple, some people will just take collateral for the tool rental. I do it all the time.

[mfewtrail]

Being a 3100, the lower intake gasket is also a possibility. Check all the hoses you can visually. Renting a pressure tester as Rich suggested would be ideal. With it you can narrow down the source of the leak within minutes in most cases.

 

 

I'm moving your topic to the appropriate section by the way(powertrain).

[pitzel]

There's a pipe on these cars that wraps from the heater core, around the passenger side of the engine compartment, almost into the wheel well, and back up to the water pump area on the front. A portion of this assembly is made of steel which eventually corrodes, and causes pinhole leaks, particularly at the places where the tabs are welded to the pipe to insert the screws.

 

Get in there and inspect that pipe if you are drawing a blank everywhere else. Mine was so rotted out that I was able to puncture it with my fingers, yet it didn't dump literally all of the coolant out.

 

BTW, peak pressures and temperatures in most automotive coolant systems occur after shut-down. When the coolant pump is no longer moving fluid through the system, but the block itself is still very hot and attempting to conduct heat into the coolant.

Edited April 13, 2015 by pitzel