Tailpipe Steam

[grnlantern1]

Hope someone can help..After about 20 minutes in stop and go traffic I notice steam coming from my tail pipe the engine doesn't seem to be getting hot and after I'm on the open road it appears to go away. When I get to my destination I keep the engine running and check my exhaust and everyhing seems normal. I'm think it's a possible head gasket problem but I don't see any other signs..Some times I hear a water swishing noise coming from inside the truck like water is being pushed through the the heater core and when I check my radiator it appears to be low, but nothing is being pulled from my overflow bottle. If some has any good ideas please chime in.

[sport03]

The valve stem seals are what cause the white, bluish smoke to come out of the tailpipe when idling for 15-20 minutes and its common for those to go bad. As for the water swishing noise, I noticed that I hear that noise only when I'm low on coolant for some odd reason