Waterfall sound under dash - The 1947 - Present Chevrolet & GMC Truck Message Board Network

91Sportside · 12-05-2008, 12:26 PM

My 2001 Silverado, 4.3L, manual transmission has a waterfall sound under the dash when driving. I suspect air in the cooling system, but don't know how to get it out. When I take the expansion tank cap off, there is no pressure, the truck doesn't overheat and the heater blows good and hot.
I suspect that I also have an intake manifold leak, but have put a bottle of BG cooling system sealer in the system and the leak seems to have stopped.
Any ideas?
Steve 91Sportside

WELD4DAYS · 12-05-2008, 01:44 PM

I have a 2002 Silverado with the 4.3 also. Same thing with the water sound. It seems like I hear it every morning when I start it up and drive away. It stops after a few minutes. I think I have a coolant leak some where. My coolant light comes on every so often.I top it off and the light goes off. Its obvious that the water is going some place.I hope to hear others on the subject.I heard about water pump issues.

ctouchet · 12-05-2008, 02:14 PM

i have the same noise in my 2006 2500HD

cmart · 12-05-2008, 02:29 PM

My 99 5.3L does the same thing and the "Low Coolant" light has been coming on the dash as well. I've noticed that when you shut the truck off and turn it back on the light is gone. That's puzzled me.

I'm very anxious for someone to chime in on this one that knows what they're talking about.

Cory

MD8349 · 12-12-2008, 05:52 AM

You have a leak in your heater core.

cmart · 12-12-2008, 09:57 AM

Is that something a somewhat mechanically inclined person can change out? Are they very expensive?

stepside67 · 12-14-2008, 08:01 PM

Same thing with my 2000 Silverado 4.8L V8. Turned out to be low on coolant due to water pump leaking. From what I understand this is a pretty common problem with water pumps on this model. The noise is due to coolant being low and when the rpms go up the water pump pushes water into the heater core.

Blue_71 · 12-15-2008, 12:57 AM

4.8-6.0s have problems with water pumps leaking
4.3s have problems with thermostats going bad and intake gaskets leaking.

the ONLY way i have found to remove air from the coolant system on the trucks that you have to fill from the overflow tank, is with a special tool called an Airlift

12-05-2008, 12:26 PM	#1
91Sportside Registered User Join Date: Oct 2004 Location: Victor, NY Posts: 21	Waterfall sound under dash My 2001 Silverado, 4.3L, manual transmission has a waterfall sound under the dash when driving. I suspect air in the cooling system, but don't know how to get it out. When I take the expansion tank cap off, there is no pressure, the truck doesn't overheat and the heater blows good and hot. I suspect that I also have an intake manifold leak, but have put a bottle of BG cooling system sealer in the system and the leak seems to have stopped. Any ideas? Steve 91Sportside

12-05-2008, 01:44 PM	#2
WELD4DAYS Registered User Join Date: Nov 2007 Location: Phoenix,AZ Posts: 107	Re: Waterfall sound under dash I have a 2002 Silverado with the 4.3 also. Same thing with the water sound. It seems like I hear it every morning when I start it up and drive away. It stops after a few minutes. I think I have a coolant leak some where. My coolant light comes on every so often.I top it off and the light goes off. Its obvious that the water is going some place.I hope to hear others on the subject.I heard about water pump issues.

12-05-2008, 02:14 PM	#3
ctouchet Registered User Join Date: Nov 2005 Location: Maurice,Louisiana Posts: 169	Re: Waterfall sound under dash i have the same noise in my 2006 2500HD __________________ 2012 F150 SuperCrew 2011 GMC 1500 (COMPANY TRUCK) 1982 Chevy Blazer 2WD (Work in Progress)

12-05-2008, 02:29 PM	#4
cmart Registered User Join Date: Nov 2008 Location: Nashville, TN Posts: 46	Re: Waterfall sound under dash My 99 5.3L does the same thing and the "Low Coolant" light has been coming on the dash as well. I've noticed that when you shut the truck off and turn it back on the light is gone. That's puzzled me. I'm very anxious for someone to chime in on this one that knows what they're talking about. Cory __________________ 1999 Chevrolet Silverado 1500 extended cab, short bed. 5.3L automatic.

12-12-2008, 05:52 AM	#5
MD8349 1999 Chevy Join Date: May 2004 Location: DALLAS, TX Posts: 61	Re: Waterfall sound under dash You have a leak in your heater core.

12-12-2008, 09:57 AM	#6
cmart Registered User Join Date: Nov 2008 Location: Nashville, TN Posts: 46	Re: Waterfall sound under dash Is that something a somewhat mechanically inclined person can change out? Are they very expensive? __________________ 1999 Chevrolet Silverado 1500 extended cab, short bed. 5.3L automatic.

12-14-2008, 08:01 PM	#7
stepside67 Registered User Join Date: May 2005 Location: Cypress,Tx Posts: 63	Re: Waterfall sound under dash Same thing with my 2000 Silverado 4.8L V8. Turned out to be low on coolant due to water pump leaking. From what I understand this is a pretty common problem with water pumps on this model. The noise is due to coolant being low and when the rpms go up the water pump pushes water into the heater core. __________________ Stepside67 2016 Silverado LTZ Crew Cab 2001 Suburban 2000 Sportside Reg Cab 4.8 (Stolen) 1967 SWB Stepside Project

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