Hello y’all i need to replace my heater core as my car blows air but does not blow hot or warm. Any suggestions on the best way to go though the process? Open to all and any suggestions. Thanks for you time.

 

 

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My car is a 1976 280z if that makes a difference between all the models.


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Unless the heater core is plugged up completely then there is prob something else that would account for no heat. Now if the heater core is leaking they it def needs to be addressed. there are options other can suggest that can be made to fit that are not Nissan, and are commonly available. OR you can pull the core and take it to a rad shop that should be able to repair it. IF the core is not plugged or leaking I would think you should start by confirming the rest of the system starting with proper hook up of hoses, then function of the various valves and the hook up of the various doors inside the plenum that direct the air flow thru the system. The FSM is good at explaining all the vacuum servos/doors/control levers etc...

Edited March 8, 20205 yr by Dave WM

What Dave said ^  I'm thinking it's either the heater valve itself or the stiff wire that actuates it.

Do you have it connected to the head with the 2 hoses?

My barrel connector for the wire to the valve came loose and wouldn't pull the valve open.  You can move it with your hands.  Back towards the seat opens it for heat, forward to the engine bay closes it.

 

10 hours ago, turbo280z said:

Hello y’all i need to replace my heater core as my car blows air but does not blow hot or warm. Any suggestions on the best way to go though the process? Open to all and any suggestions. Thanks for you time.

How are you testing for heat? Turning fan on and moving temperature selector to hot?

Note: the heated air is not designed to come out of the vents.

In order to get heat, the mode lever of the control unit needs to be in "Bi-Level",  "Heat" or "Defrost"

 

If the vacuum hose to the vacuum canister leaks you won't get heat.  The vacuum cark needs vacuum to expose the heater core.

I have the two hoses but they were cut by previous owner I guessing because the core starter to leak inside the car 

Might just be the hoses to the core inside the car that leaked.  Not the core.  They're hard to reach so it's easier to just take the core out of the loop.

Agree with Zed Head. I can't remember reading of a leaking core. It's always the valve or loose hoses. 

It's a pretty tough job too. I did mine just for defrosting the windshield.

I am betting the valve was leaking.

Let's diagnose before you go after the heater core

Okay thank you guys I will look more into the valves. I’ve heard the heater core is a pain. I am currently working on fixing my window regulater