Using coolant?
 

I have a 2002 Silverado with the 4.3. About 87,000 miles. I have the water fall sound under the dash.I have to fill up my coolant every so often. I think its using a little more as time goes on. I heard these motors might have intake issues or water pump problems. I never see water on the ground. Maybe it leaks internally and is evaporating. My question is, can I put some of the old school stop leak in the overflow tank. The gray powder stuff you might use on your old Chevy? I'm not sure how the newer vehicles might react to something like that. Please give me your thoughts. Thanks

Re: Using coolant?
 

do not use stop leaking in a new vechicle it sounds liek your heater core is going out

Re: Using coolant?
 

i have a 2002 silverado same eng 4.3 with 55,000 miles i can smell coolant just about everytime i drive it but don't see any leaks. but it hasn't got low but 1 time i pull about a quart in it. i was thinking maybe the water pump is getting ready to go out. it does not run hot either.

Re: Using coolant?
 

The 4.3L is prone to the intake leaks that the 5.0/5.7L Gen I Vortecs suffer from. Check you oil and see if it is higher than normal. Also remove your oil fill cap and look for a light colored sludge stuck to it. The oil will get hot enough to cook off some of the water and the vapor collects as a oily white sludge at the top of the engine, valve covers and in the crankcase ventilation route.The waterfall sound on the NBS trucks generally is due to air circulating through the heater core due to low coolant. Another indicator of low coolant is the heater really won't blow hot until the truck starts moving. If you do suspect intake gaskets, get a Chilton manual and make sure to get the Fel Pro Problem Solver Gasket Set #MS98002T. This set has the newest rubber-over-steel design that replaces the OEM rubber-inbedded-in plastic design. The water pump leak issues only apply to the V8 Gen III small blocks (4.8, 5.3, 6.0).
It is also possible for these to leak externally. Look at the rear of the pass side head and down the front of the driver side head for a trail of burned off coolant.