I keep having to add coolant (to the overflow bottle) to my '96 4X4 5.2L. In about a month it goes from the full line to half empty. When I change the oil, it looks clean (no foamy, choclatey mess) so I don't think it's the head gaskets. No leaks on the ground.

Any ideas?

 

if you have no other visible leaks, steam, stain, smell, or whatever, then its probably the seal around the water pump shaft. as they get old and wear out, that seal begins to leak very very very slowly. if thats it, it will gradually get worse and you will begin to see steam or drip. one other possibility is a crack or leak in the overflow tank. how old is your waterpump ? if very old, you might want to go ahead and starting planning the repair, as its an excellent time to fix the plenum, timing chain, tune up, etc.

just keep it full of coolant and it may last another year or two. i would recommend you NOT put stop leak in it unless you can find an acutal visible radiator leak.

 

When I parked my oldtruck on a steep ditch to fish or hunt I would loose fluid.
Other than that I overheated my truck once and had it gushing out when I got to work.
I would look into that dye stuff and use a black light and look for leaks.
Napa sells it.

 

my 01 ram with the 5.2 does the same thing.. you wont ever see it.. but check this out.. where the heater hoses connect to the heater coil.. they like to leak right there.. very slow.. you dont see it because it drips down the firewall... mine if you catch it just right.. you will see it dripping off of the transfer case.. odd.. but it leaks down that way and drips off of there.. i havent fixed it yet.. i should soon im sure.. but im thinking a couple new clamps and trim the hose some it should be fixed

 

Thanks for the tips, guys. I forgot to mention that the radiator, water pump and heater core are only two years/15K miles old.
Dishdue2k, it sounds like you may be on to something. I'll check your suggestion