Water sound from behind my dash??
- Thread starter Draayer
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Brian757
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I would almost think heater core. You might either be low on coolant which could allow for air to get into the lines. At which point, you would hear what sounds like a mini waterfall in your dash. Or you could have a bad heater core which is leaking into your cabin, but most cases, you would notice that.
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Brian757
New member
I have never bled the coolant line on a 4runner but I have on my Passat.
There is an inlet and outlet running through the firewall into the heater core inside the dash. You access these lines through the engine bay. The outlet hose has a small hole right where it connects to the firewall, you pull the hose back far enough to where it is still connected but the hole is exposed to open air. You then hop in your vehicle and give it gas. It will show bubbles on top of the hole signifying air escaping.Turn on the heat until coolant begins shooting out of the hole. You walk over and push the hose back on tightly, you have just bled the line.
Although, attempt this fix but if it goes away for some time and returns, then your coolant line somewhere is receiving air, meaning you COULD have yourself a leak. Not trying to scare you.
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Brian757
New member
I flushed my Passat as well. I did what some say is a bad idea, but I put CLR in the inlet line and let it sit for about 20 minutes. I then ran the hose through the inlet and had a long outlet hose attached and running to a bucket to collect material for inspecting, also, coolant is bad to let run-off.
I got so much gunk and build up. I actually did this because she wasn't getting ANY heat whatsoever and the windshield wouldn't defrost. I ended up flushing my inlet and outlet 4 days in a row and now she gets good heat.
The trickle sound could be a number of things:
1) A clog in the heater core or inlet/outlet line which slows water movement and creates a dripping affect, causing the sound you hear.
FIX: Just flush the lines repetitively, first through the inlet line, then through the outlet line.
2) Air in your lines.
FIX: Just needs to be bled.
3) Low coolant level.
FIX: Check your coolant reservoir and/or radiator. Fill to appropriate level. Start engine, monitor coolant level in reservoir.
As long as your getting heat, then ANY of your fixes will be a DIY and not costly. Just act quickly because if it is a clog near your heater core and it is left over a long period of time, it can harm the heater core and potentially break it.
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ATX4Yota
New member
Old thread but having the same issue as the OP...trickling water sound behind my dash. My heater works like a champ and carpet/floors in the driver and passenger footwells are bone dry. The trickling only happens when the heater is on during a cold start and seems to last until the engine approaches operating temperature. I've never noticed the sound when the heater is off.
I noticed the coolant was low a few weeks ago and found that a hose clamp at the bottom of the radiator was broken. I drained the radiator and engine of coolant, replaced the hose clamp, filled with distilled water, ran engine for several thermostat cycles (heater on), drained radiator and engine and filled with 50/50 coolant. I bled the system (heater on) for about 20 minutes with front of 4runner on an incline and radiator cap off.
I turned the heater on right after a cold start this morning and the gurgle/trickle is still present. I bled the cooling system for a good 30 minutes this afternoon and got quite a few air bubbles out. I've checked the radiator and all heater hoses for obvious leaks and my coolant level is not dropping. If the gurgling continues, I'll try flushing the heater core and replacing the radiator cap next. If anyone has suggestions, I'd be glad to hear them...
I noticed the coolant was low a few weeks ago and found that a hose clamp at the bottom of the radiator was broken. I drained the radiator and engine of coolant, replaced the hose clamp, filled with distilled water, ran engine for several thermostat cycles (heater on), drained radiator and engine and filled with 50/50 coolant. I bled the system (heater on) for about 20 minutes with front of 4runner on an incline and radiator cap off.
I turned the heater on right after a cold start this morning and the gurgle/trickle is still present. I bled the cooling system for a good 30 minutes this afternoon and got quite a few air bubbles out. I've checked the radiator and all heater hoses for obvious leaks and my coolant level is not dropping. If the gurgling continues, I'll try flushing the heater core and replacing the radiator cap next. If anyone has suggestions, I'd be glad to hear them...
I'm having a similar issue with my 2002 SR5. The car is not being driven in the rain and I've checked the sunroof drain tubes (they're clear -- water feeds to under the car). Water accumulates behind the dash after a heavy downpour. If I make a hard right turn, water gushes onto my foot on the brake pedal, if I make a hard left, it drips into the passenger foot well and I hear sizzling (must be heater core). I'm convinced it's happening because of water from the vent register between the hood and the windshield. Where's the drain for that vent?
