Bypassing Heater Core

[Weasel73240Z]

I think I'm going to bypass the heater core in my 73. I know I'm in Massachusetts, but this is strictly going to be a sunny, Summer day car, so no need for heat. Plus I think the heater core may leak, so who needs it.

I know this has sort of been covered, but I just want to make sure I don't screw anything up. So I'm just going to cap off the core lines coming through the firewall. Then I should just run a line from the back of the cylinder head to the radiator outlet on the passenger side of the block, right?

I know a previous post that I found while searching talked about eliminating the outlet on the back of the cylinder head, but I can't see why I'd do that. Thanks in advance for the help.

Oh yeah, and Go Sox!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[240ZMan]

Your plan should work fine. IIRC, on my 73 there used to be a separate small line that tapped off the coolant outlet at the rear of the head and went around to the other side. It has been a few years since I took it off so don't remember the details very well, but perhaps that is what the previous post was discussing?

Also, the two fittings are different sizes so you'll need to create an adapter. Here's a picture of how I did it, and used a bolt into the side of the block to support it. I did have to bend the dipstick to clear.

[CA280]

The reasoning to block this is to prevent overheating. With the heater valve in place the loop is normally closed, when the valve is open the coolant cools through the heater core, with it looped open, the hot coolant is returned directly to the engine without cooling and can contribute to overheating. In AZ and So. Cal this makes a difference.

[sblake01]

Month old stuff but the best thing to do if the heater core leaks is fix or replace. It's a pain of a job and I had actually bypassed mine but only until I found a core. The weather does get cold in the winter even in California and Arizona.