Coolant Bypass

[VonMussa]

As I work through this, just confirming the coolant is bypassed appropriately around to avoid the heater?

[JT68]

Yes, that is fine, won't hurt anything if you are looking to bypass the heater for a while.

[VonMussa]

Appreciate it. Bought it and trying to unpack whats been done right, and whats been done wrong.

[JT68]

Long term, I'm sure you will want a heater and water through the manifold I'd think, but that will work fine for now.

[VonMussa]

Yes. Definitely need a heater living here in Michigan. Top down as the snow falls is my goal

[mshort07]

It was suggested to me by someone on this site to bypass the heater core after the coolant passes through the intake manifold and just before it enters the heater core. The individual suggested that the heated coolant in the intake manifold helps to preheat the air fuel mixer entering the combustion chamber.

[Nissanman]

From what I have read, the heated manifold [throttle body on EFI engines] is designed to minimise the likelihood of the throttles jamming open due to icing up in humid climates.

[JT68]

Coolant through the manifold simply regulates the intake manifold temp. Helps warm up the intake and carbs in the winter, keeps the manifold cool in Arizona. Plenty of cars run dry manifolds, but if you are running the car in extreme temps, a wet manifold is a good plan.

[Jorge0227]

I know this post is a few months old, but I need help in this field. I am finally working on my '68 1600 again after letting it seat for a while. I have the heater, but didn't install it back (I live in Palm Springs, CA where "winter" means 60 degrees. Back then (haven't started the car in 5 years, working on doing that within the next couple of weeks) I was adviced to create a loop out of the brass valve (where it is supposed to go to the heater core) and the water line going under the heat shield (I included pictures...I hope they show correctly). I would like to eliminate redudndant and/or unnecessary hoses. I also have the problem of the brass valve leaking. Thoughts?

[mraitch]

1) looking at the photo - strongly suggest suggest replacing short hose running from the front of the coolant tube to the block . It looks like it is bulging and might we appropriately addressed NOW.

2) AFAIK The purpose of the valve is to completely BYPASS circulation into the heater (though why NISSAN bothered to introduce that complexity is beyond me, since there are levers/switches that turn it on/off etc..

It's a bit of a bugger to get at, but easy to take apart, clean and reassemble (it's spring loaded, so don't lose the spring) .

Should clear leak.

Rather than dealing with the 'issue' in the engine compartment, leave all alone and just run a hose inside of the 'cockpit' that connects the intake coolant to the "outtake" coolant, i.e. bypassing the location of the non-existent heater. That's currently how Eliza runs.

HTH

[Jorge0227]

Sounds good! Thank you for the information and advice.