I had to replace the heater core a few years ago and it was a hassle. Since I will be pulling the engine to replace a freeze plug going bad I am thinking about bypassing the heater core when I reinstall the engine. Really don't use the heater down here in south Texas, so this may be the time to bypass a future problem. Have any of you bypassed the heater core and run directly from the water pump to the head? If so, how did you handle the 5/8" vs 3/4" difference? Thanks.
I have never used them but I believe they sell caps to block off the nipples so that you don't need to worry about hose failure either. Maybe someone else that has them can chime in.
If you're going to bypass your heater core, use the above mentioned Dorman tube, and install NEW quality hoses and keep the coolant circulating. I keep the block off caps in the glove box, in case I have a hose to break.
The best thing to do is plug it at the head and water pump so the coolant will pass all the way through the head where it belongs. Unfortunately those block off plugs are meant for temporary use. I had mine blocked off with those plugs at one time and when I removed them they looked like they were going to fail at any time. For that reason running a bypass hose may be the best route unless you can come up with a more permanent plug method. A half assed but effective way would be to use short pieces of hose and insert some sort of plug and hose clamp it up.
Thanks for the information. I am not familiar with block off caps - just so I understand - the hose caps are applied after you remove the hose? One cap at the water pump and the other at the head nipple?
I am just seeing this again and agree with what Bob S said, racers have been blocking those off for decades with no ill effects and in fact Pontiac itself started blocking the flow to the core in 69 using a vacuum controlled shutoff in cars with a/c. This was done to combat the radiant heat from having a very hot heater core under the dash. Even though the blend doors were shut so the incoming fresh air couldn't push it through the vents it caused the whole heater box under the dash to convect heat fighting the a/c in 7s and 8s. Being in a hot climate you are smart to stop this. Just to revisit your original question, a couple of ways I have thought about stopping the flow to combat this in the summer months and still keep it original looking is one: have a couple of pieces of brass or aluminum turned down on a lathe to just fit inside the hoses and install in the ends of the hoses with an extra clamp around them to make sure they stay in place. or two install 2 shut off valves in the most inconspicuous place on both hoses so even convection heat from the other hose could not get to it. a lot of cars including foreign used these on the inlet hose from the late 60s on. The other option would be pcv ball valves. It's to bad the block offs they offer aren't any good because that's the best non original way to go. Unfortunately in all the first gen birds I have owned and seen through the years I have never seen an original heater delete car. Probably being from the northeast doesn't help.
