[joe123999]

Thanks for everyones input. I was glad to find a solution for the coolent leak in the intake for my. I replaced the upper manifold in an afternoon. It is holding after 2-days. I hope I never have to do this again.

Coming from a engineering background I was shocked to see the how the coolent ran from the lower intake manifold to the throttle body (through the PLASTIC upper manifold). This must have been a bandaided last minute solution by the engine manufacturer. My guess is the throttle body iced up and wasn't found till too late. The quickest and cheapest solution was probably to route the coolent through the upper intake manifold. The real solution could have been to short the intake manifold and lengthen the throttle body. The coolent should never have been run to the throttle body this way. The coolent and the EGR exhaust port probably should run through metal-to-metal surfaces only. Another factor that could cause the upper intake and throttle body gaskets to is wear from vibration. My throttle body had a one bracket supporting it to the lower intake or head. Combine the vibration with heat and you know the rest, a hybrid engine that runs on gasoline and Dex-cool.

A posible design fix could have to design the manifold so the coolent doesn't leak into the intake and leak. A couple extra gasket linings would have done this.

Also, the EGR is definitely shouldn't be close to a plastic surface. Maybe this should have been ported directly to the throttle body, therby reducing the need for the coolent to supply the heat.