I have done a search and haven't found the info I am looking for, so I hope someone can shed some light for me. For no necessary reason other than fiddling, I added some Dexcool and water to my overflow tank to bring the level up. Since then, there has been coolant dripping underneath the front end. I had my water pump replaced at a GM dealer two years ago, so I doubt it is a bad pump. Question: If you overfill the reservoir, will coolant leak out from somewhere on the radiator until the level of fluid is back down or do I have a leak and/or a bad water pump? There is still plenty of fluid in the reservoir. What symptoms would point towards a bad water pump? Perhaps does my reservoir cap need to be replaced? Any help would be greatly appreciated!

Bryan

 

funny thing about water pumps....no guarantee on life....

you really need to figure out where the leak is coming from...may wanna check the T connection under the resevoir as well...or possibly one of the hoses is leaking

 

You aren't very specific about where you see the leak coming from but if you've overfilled the coolant reservoir it will leak onto the ground. You'll have to trace the vent tube and see if you can find the source of your leak. You don't fill the tank to the top, the coolant needs room for expansion when it gets hot.

 

I didn't fill the reservoir up to the top, only a tad above the "COLD" line. The leak seems to be coming from under the hoses, not from under the water pump. Maybe I have a bad hose....

 

NO! Adding water to the reservoir tank should NOT cause any sort of leaks anywhere else (if you only added fluid to the FULL HOT or FULL COLD mark. The system should be sealed and when at operating temp, there should be pressure in the system. If there is an "AIR" space inside the reservoir tank, you should be fine. If for some reason you filled it up to the rim with fluid, the only place that the fluid could expand would be a hose or possibly cause the water pump seal to blow.

Try to pin point where you see the water pooling up. That will give you a better idea where it could be coming from. You have a 98 so,,, the belt drive pulley on the pump is able to be removed to inspect the small weep hole in the pump for water/fluid. Remove the belt and the four fasteners that secure the pulley to the pump. If you had a late 99 -2004 C5, the drive pulley is pressed on to the pump and can not be removed (by normal everyday C5 people ).

Are you sure it DEXCOOL Coolant taht your seeing?? Remember,,, the HVAC system has a drain that will dump condensation on the ground! It leaks out on the passengers side near the starter. The drain is on the fire wall!

BC

 

Thanks Bill for the help. Since I had the water pump replaced two years ago by a GM dealer, parts and labor are covered for life. So, they are going to do a pressure test and if it is the water pump, they will replace it at no charge. If it is something else, then.....