I've just finished replacing the metal coolant tube under the intake manifold ('99 5.4L). Probably a total of 10 hours due to having to remove the manifold for the first time. This was all caused by putting GM coolant in the engine accidentally. Who knew? It really does eat the water pump and the rest of the metal... I had absolutely NO "fins" on my water pump.

My problem is that I can't determine which way to re-attach the inlet and outlet hoses to the heater core through the firewall. Which side is which or does it even matter? Does the water pump pull water through the core or push it? I think the tube that I just replaced has water flowing from the core to the water pump but can't really confirm this.

Can anyone help?

Thanks.

 

 

the 90 degree gives it away.....