Coolant leak/ slushing sound behind dash


Well-Known Member
Jan 2, 2011
Shreveport, LA
Ok let's see. November my thermostat went out. Replaced it and all has been good. January or so I started hearing water slushing around behind dash when turning or idling. Sounds like fuckin waves crashing on a beach.

Popped hood few weeks ago and coolant tank was completely empty. Topped it off. Next day saw coolant dripping where the heater hoses meet the firewall. Passenger side floorboard is dry. No coolant leaking there.

Today started smelling the coolant in the I was in traffic steam came from under hood and I pulled over and popped hood and it seem to be leaking on engine or headers and just burning off into steam whatever.

Y'all think its just the 2 hoses leaking at the firewall or possibly hole in hose or heater core gone bad? I'm really hoping its just the 2 hoses but.

2007 nnbs Silverado 60,000 miles
Last edited:


The LED Man
Apr 6, 2012
Don't those hoses go on some plastic fittings at the firewall? If so, one of those might be cracked and leaking at the firewall. If I get some time, I can look at it with you one day and maybe I can help you narrow it down. Shoot me a text.