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Heater doesn't work, could this be why?


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I'm trying to learn more about the workings of shit. I've opted to have things fixed instead of fixing them myself because I've generally been lazy, and I'd rather drive my car than curse at it...But I acknowledge that these are things I need to know, if I want to be able to be proud of anything I drive...so forgive my general incompetence. I can learn...How quickly is questionable, but I can learn...

 

So, I actually just need to know if this could be the reason why my vents only blow cold air regardless of setting:

One. Hoses looped.

Two: Closer look.

Three: Different hose, just hanging.

Four: Where it connects. You can see the alternator if it helps give a sense of where this is.

 

Also, the only vents that work at all are in the center, above the stereo. I'm reasonably sure it's unrelated, but any possible explanations for that before I go tearing my dash off would be much appreciated.

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I'm not sure why that short 90* hose is there. All my L-4 engines had a similar layout but without that hose. The L24 in my 240 was the same as as the 4cyls too. Maybe the later L-6s has that but I can't see why. It essentially bypasses the heater core instead of forcing hot coolant through it. Yes, your vent problem is unrelated.

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Good to know the workings of shit.......... :D

Seems your hoses are somewhat connected.... :blink: ...eliminate the tees.

Out of head into heater...out of heater (directly) to water pump.....no tees

Based on my L config

 

UzFGZ.jpg

 

Oh...and ditch the Fram

 

http://community.rat...wix-comparison/

 

So then that connector shouldn't be there at all? What would be the purpose of having it there to begin with?

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First that Fram filter needs to be gotten rid of ASAP!!!!!!!!!

 

Next the pipe from the head should go to the heater (either side will work) If there is a T at the head outlet plug the other side.

The other hose from the heater goes to the front of the motor and connects to where the lower rad hose enters the timing cover. (upper left corner in the picture below}...

 

4mIMd.jpg

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I had a 280z once and my heater wasnt working.

I was going to rip out the colum to find the heater valve.

Then a guy showed me a vacuum line that went to a funky cannister and hooked it up then my heater was working. Hot air out

 

Funky canister, you say? The empty hose I'm holding in one of the pictures is hooked to one of those...Of course a lot of the non-obvious parts are "funky somethings" to me. :P

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FWIW: I'm a 510 guy, but I had heater probs. diagnosis as follows: radiator leak = no heat, low coolant = no heat, bad (not plugged) heater core = no heat. With that emission-fancy luxo barge you got there, I can't be much help. BUT! Skimming the posts, it sounds like you need to give the cooling system a once-over. Well, that, and get rid of your FRAM filter (I worked in auto parts, we cut one open for comparison to good filters, there were insects in it, trufax). I don't know how much more complicated a 78 is vs a 71, but you can prolly figure it out. Hoses to nowhere is a red flag. Make sure you listen to ANYTHING Datzenmike says. And +1 on Sealig's "wtf 90 degree hose" comment. A Hanes manual will help you a ton and you need it. Best of luck.

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Is your Z a factory air conditioning equipped car? Mine had this exact problem - it was due to a vacuum leak at the air conditioning solenoid thingies that sit next to the voltage regulator on the engine bay side of the passenger fender. replaced the vacuum line, and had full functionality. No need to tear apart the dash. Defog is an awesome thing to have in the pnw.

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Your water lines look fine on the back of the head. The 280Z/280ZX had that setup.

 

When you close the valve in front of the heater core the water pressure will flow right to the head and bypass the hoses going into the cabin of the car.

At least thats what I think it is for. Relieves some backpressure.

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Funky canister, you say? The empty hose I'm holding in one of the pictures is hooked to one of those...Of course a lot of the non-obvious parts are "funky somethings" to me. :P

 

Could the funky canister be the factory AC solenoids? They control the vacuum flow to the vent switching actuators (as far as I can tell). I have procured an image of a factory AC engine bay from teh webz and circled the solenoids, and their source of vacuum. This was the source of the problem for me, one of the lines had split at the solenoid, and neither of them got sufficient vacuum to actuate the vent switch thingies.

mFfOC.jpg

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Could the funky canister be the factory AC solenoids? They control the vacuum flow to the vent switching actuators (as far as I can tell). I have procured an image of a factory AC engine bay from teh webz and circled the solenoids, and their source of vacuum. This was the source of the problem for me, one of the lines had split at the solenoid, and neither of them got sufficient vacuum to actuate the vent switch thingies.

 

1zyc6.png

 

THAT would be the canister.

 

Is your Z a factory air conditioning equipped car? Mine had this exact problem - it was due to a vacuum leak at the air conditioning solenoid thingies that sit next to the voltage regulator on the engine bay side of the passenger fender. replaced the vacuum line, and had full functionality. No need to tear apart the dash. Defog is an awesome thing to have in the pnw.

 

 

and yes, it came with A/C.

 

EDIT:

More pictures:

hG0A2.jpg

Here's another angle of the hoses. One hose comes out of the head, and into heater, but also 90* into hose coming FROM the heater out towards the water pump(?).

 

ALSO, because of Interrobang I went out and poked around some more. I found this hanging off the bottom of the A/C solenoids:

3aQXJ.jpg

 

I also found this coming out from near where the hoses I've been talking about are:

b1tXe.jpg

 

Caveman bang rock together, make fire:

nVzrk.jpg

 

Now I can get hot air out of the defroster vent (which suddenly works.) but it's kind of a weak flow even at full blast , and I still get cold air out of any other vent. This leads me to believe what I did wasn't correct but it felt like a small victory to me considering I suddenly had a defroster, even if an intermittent one.

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THAT would be the canister.

That is the charcoal canister. Has nothing to do with the heater - it's part of the emissions equipment.

 

and yes, it came with A/C.

 

So, first step would be to check the vacuum lines that that connect ot the things that I circled. This is what controls vent selection in a factory AC 280z.

EDIT: Looks like you got it while I was posting. Nice.

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That is the charcoal canister. Has nothing to do with the heater - it's part of the emissions equipment.

 

 

 

So, first step would be to check the vacuum lines that that connect ot the things that I circled. This is what controls vent selection in a factory AC 280z.

 

Already did, perhaps incorrectly, but I did.

Just edited my last post. :D

 

From/to the areas circled the vacuum lines are fine.

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Already did, perhaps incorrectly, but I did.

Just edited my last post. :D

 

From/to the areas circled the vacuum lines are fine.

 

In my Z, hot air can only come out of the defroster vent, or the floor vent - the center and side vents only blow cold. I think that this is how they came from the factory, but I would have to double check my owner's manual to be sure. The floor vent is opened by a rod and flap which can stick - I had to WD-40 mine and wiggle it open to get it to work.

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In my Z, hot air can only come out of the defroster vent, or the floor vent - the center and side vents only blow cold. I think that this is how they came from the factory, but I would have to double check my owner's manual to be sure. The floor vent is opened by a rod and flap which can stick - I had to WD-40 mine and wiggle it open to get it to work.

 

Only from defroster and floor? That seems really strange. Can anyone else confirm that for me? (Or if you can confirm from the owner's manual)

 

I still have the problem that it's a really weak air-flow...Probably just worn-out fan related?

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  • 3 years later...

Iv got heater problems too. I have the top inlet of the heater routed to the front Right side of the water pump area.

I have the outlet routed to the back of the engine @ the head.

 

Now the outlet side has about a foot of hose going in a "loop" so

It could be having issues with cycling. Secondly, pulled heater core

Out, ran water through with air to force it and seems ok. As far as my newbe knolage

Goes. Now I did call it s night once the core stared having spiders crawl out so now I'm

Finnishing my research here..... With you guys...... I had my mouth on the heater core inlets....

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  • 1 year later...

I don't mean to pull up this topic again but I need help on this I have a 1979 datsun 620 the heater core was disconnected when a hose blew on it and is bypassed I still have a lot of work on this truck and I am currently driving it daily and am learning still on this old thing the heater core has been bypassed since I purchased it. I want to know how to run the lines back I will get pictures if needed.

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should be 2 holes on the firewall. one goes to the head. the other to the intake water spout under the fuel pumpor above the alternator area.  dont know which is which. but might not matter. dealer has photos or datzenmike will know abd get photos

 

I dont get why just didnt buy another hose from the dealer instead of bypassing it. Bypass is for a quick ride home then fix it.

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