In my 98'chevy truck i can't keep antifreeze in the overflow jug everytime it is gone i refill it to the "cold" level but it seems to disappear.I checked pass.side floorboard to see if heater core was bad but the area is bone dry.There is no milky substance on dipstick or in oil where is it going and what could be the problem? Thanx.

Check for a pinhole leak in the front side of the radiator. It will only leak when hot and be such a fine mist that you may not even notice. Also, you could have had a lot of air in the system.

Haven't noticed any leaks but will check it out.There would have to be an awful lot of air in my system in order to justify this scenario.

libb58, my 2000 Silverado just started doing same thing... have found nothing.... I might be checking spark plugs soon for signs of a head gasket.

its the water pump.
I had mine replaced 3 months ago.
coolant was weeping past the seal.
to verify this place a sizable piece of cardboard under the engine and radiator.
leave it like that all night .
look for wet spot or discoloration on the cardboard the next morning

Good suggestions given by all. Use a good flashlight and look for white trails, signs of a leak. Check bottom hole of water hole casing.

If you remove spark plugs and you find a very clean one, pump some shop air into the combustion chamber and check for bubbles in coolant at radiator cap.

Check the intake also, the vortec 5.7 is bad about eating intake gaskets! Don't ask me how I know this!
Bill

Thanx 4 the advice fellas this is a great resource to be a part of!


73'camaro,350/400hp,muncie m-21,richmond 3.73 posi 10-bolt.