My son is smelling antifreeze in his car and yesterday after a long trip at 75 mph he found a small amount of antifreeze on the passenger side carpet. I assume heater core or something, we pulled off a lot of the dash as we could in the rain but see no obvious place it's leaking, after leaving the car running we still see nothing but can smell it. Maybe a pinhole thing. The puddle was about 3 tbls

Since we don't have a garage to get into and want to get through the rain, here's the question we need some advice on. 

I've read that you shouldn't bypass the heater core lines you should plug them on this 78 280z. What we were thinking is, bypass or plug it until we get a day without rain so we can get in, pull the core out and see if it's plugged, leaking on a hose we can't find, or the core is leaking. 

We don't want to have it just go whoosh next time he's driving. 

The forum messages I've found are conflicting, should be bypass temporarily, or should we plug the lines? Only needs to last about a week maybe 10 days until we get some clear skies to work on it without a garage it sucks. 

bypassing I see is relatively easy and parts aren't hard to come by. I haven't found plugs that look like the way we should go. 

Any advice would help. 

 

You don't really have to block flow just make sure that it's not a wide open path back to the water pump inlet.  I "blocked" mine by just kinking the "bypass" hose.

Your leak is most likely one of the hoses from the heater core to the valves in the firewall.  Hard to reach but you can see them from underneath the glove box.

Or possibly the heater valve itself

Thank you ill check ot out