My otherwise VERY sound 2000 GMC Sierra 4x4 (5.3L) has always consumed coolant. It is none the worse, but I can't imagine that this is typical. I'd say it drinks about a quart of coolant every 2-3000 miles. Anyone else have this "problem?" Is it a problem?

 

most likely its the water pump..not enough to puddle,but they weep enough to get grimy

 

I have a 2005, which I’ve, noticed some coolant while changing the oil. It is not leaving any puddles and the truck seems to be operating fine. I don’t see any signs of fluid leaking from any of the hoses or adaptors. I referred to the Haynes Repair Manual for a clue. It stated within the water pump repair / replace section that the pump has a “weep hole”. (The hole may be located at the bottom of the pump.) The book also states "a seal protects the water pump impeller shaft bearing from contamination by the coolant. If the seal fails the weep hole will leak." I’m not sure if that’s the problem with my truck, but I figure I look for the simple clues first.

 

water pumps on gen 3 engines (5.3 and others) do tend to weep just tiny amounts..oddly,not out of the weep hols as much as at a plug in the back of the pump

 

I had this problem. Go to the dealership and buy some AC Delco cooling system seal tabs. I just crushed them up and added them to the overflow tank.

http://www.acdelco.com/html/pi_vehcare_adh.htm

 

Thanks for the information everybody. My truck is approaching 35K, I’m debating if I should take it to the Dealer and have the water pump replaced or try the tabs. Is this a matter of a poorly design water pump? If I use the tabs, should I have the system flushed first, or at 35K it really doesn’t matter?

 

the pum[p probably will get no worse..but it will not get better either..i'd git er done

 

I have a 01 sierra with the 5.3. Also was leaking coolant. My uncle has a shop so I took it there and put some die in the reservoir. He used the ultraviolet light and found it was leaking from the heads. He told me this was sort of common with these engines.

So this mightbe another optionfor theproblem, hope not for your sake though. He put some type of stop leak in it and for the last year it has been doing fine. But, it is only a temp. fix.
Good luck