Heater Doesn't blow Hot hair

[TomoHawk]

my 78 280Z will blow air that's slightly warm, but I would expect it to be on the hot side of warm. Is there anything I should check to see if it's blocked or something? As far as I know, all the controls work right.

[RB26powered74zcar]

One time I had that problem on my 260 and it was due to a vacum hose un hooked from the clear plastic vacum tank. Those little shits have a major impact on your heat and aircon....

[TomoHawk]

Yup, hoses.

Mine hose ends kept cracking at the vacuum tank, dashpot & solenoids, so I replaced all but the one going into the dash yesterday (10/15) One was so hard/brittle, I broke a piece off to take to the auto parts store!

Until then, all vacuum-operated flaps/doors were working OK. I will look into the water valve and maybe get some professional help (for the car, not me )

[Pop N Wood]

One of the true marvels of the early Z cars was they were one of the first Japanese imports with a decent heater. Should blow plenty hot.

 

First make sure your radiator is full. Seems obvious but a common cause. Then check the thermostat valve under the dash. One of the weak links in a Z car, these things tend to corrode into the closed position.

[Guest Anonymous]

I found that if all other things as previously outlined are satisfactory, the heater core may have an air bubble in it where hot water from the radiator will not circulate thru the heater core.When you replace fluids in the radator always have the heater core valve open so it can fill too.

[Guest Anonymous]

Well you could install a V8 in it, even with the heater turned off, mine gets pretty toastly inside.. Actually I need to put in some of that insulating mat, that would help the A/C work MUCH better because MUCH heat is transmitted at least in my car through the floor and transmission hump. Good luck with it.

 

Regards,

 

Lone

[Guest Perry]

never having looked at my z for this problem, in a typical car this can be a couple of things. Usually you just need to flush the cooling system, you can get a kit from the autoparts store that will allow a water hose to be hooked up and backflush the heater core and radiator. Then refill with water/coolant mix and usually it will blow hot again.

if that doesn't do it there might be a problem under the dash with the heat controls. sometimes they don't open or shut allowing air to move over the core. some cars have a water valve too which has to be open to get heat. It usually hooks to the temp control on the dash. I don't know if the Z has this valve. I guess I would proceed as follows:

1-trace water lines under dash if possible to check for water valve and make sure it opens if it is there

2- flush cooling system

3- investigate "air doors" and their controls under dash.

[TomoHawk]

I found out that the heater was actually blowing hot air. But only the heater ducts behind the console and the defroster ducts worked. I wanted hot air to come out the center dash vents. I'll leave the dash vents for next year. However, I also found out that the water was coming out the tube to the expansion tank, and ends up on the road because there wasn't an expansion tank in there! You could see the cooling tubes inside the top radiator tank, so I put a gallon of water in.