Water pump leak? 1996 Chevy C1500 4.3L

[markqc]

I noticed my coolant level goes down gradually, but don't seem to be burning any coolant. I don't see any coolant leak on the ground where the truck is parked. I noticed on the underside of the water pump a little wet spot. Is it possible that the water pump has a small leak only when the engine is running? Is there a gasket that could be the cause of the leak. The pump seems to be working ok as the temperature gage always gets to the normal operating temperature.
Thanks for any help.

[amac209]

waterpumps have whats known as a "weep hole" when the seals fail coolant slowly leaks from the hole. pressure is bult up when the engine is warm so it will leak more. go ahead and replace the pump, might as well throw in a new thermostat(cheap insurance). put a little bit of anti-sieze on the waterpump bolts before assembly since pumps do wear out and you'll probably have to change it again someday, it really sucks when a waterpump bolt snaps.
good luck

[markqc]

Thanks for your reply. I call GM for the water pump and they have two types. One is a GM for $265 and the other is AC Delco for $177. Anybody know what the difference is? The parts guy said the box is different and to buy the AC Delco pump.
Thanks

[markqc]

I replaced the water pump but still notice the smell of coolant under the hood after driving. I am watching the coolant level closely in the overflow tank and it seems to be going down ever so slowly. Almost not enough to notice. (I assume the pump was at fault for the majority of the coolant loss, but not all of the loss) Is it possible that one of the head gaskets is going. When I removed the oil filler cap at the last oil change I noticed what could possibly be a drop of some coolant. (Sort of redish orange residue but nothing noticeable in the oil) Any ideas on this?
Thanks,
Mark

[markqc]

I found out now that the slow coolant leak was the intake manifold gasket. This slow leak was probably going on for a while. Apparantly this is fairly common in the 4.3 engine as well as others.
Mark