my 240z heater is stupid! time to upgrade?

[greenz]

are there any upgrades for a 70 240z heater. even at full blast it just barely blows out any heat. im tired of wearing my ski pants to work in the morning.

Z haiku:

my 240z

i crashed it into a pole

damn you to hell pole

[Royce]

Sounds like your fan isn't working correct, the vents are not opening, or most likely your heater core is clogged up and the water is not circulating.

Can you hear the fan change speeds? If you look can you tell that the heater "trap doors" are opening when you set the control on heat? If not then more than likely there is a something pluggin up your heater lines or you have a clog in your heater core.

Sorry, no ideas on a aftermarket upgrade.

[2ManyZs]

I agree with Royce, it is more than likely a plugged heater core or something is wrong with the fan motor or vents. A heater that is properly working in a Z should just about run you out of the car. I've never heard of any upgrades because they really aren't necessary.

The first thing to check would be the fan and the heater control valve. The heater control valve controls the amount of water that is circulating through the heater core itself. Check that first, it may be the cable or not be opening due to corrosion inside. It is mounted next to the heater core under the dash on the inlet side to the heater. They are not too expensive to replace but they are kind of a pain to get to to work on.

If that seems to be working OK, check the fan motor, and the vent control cables. If it isn't that then it is probably a bad heater core.

[Daniel]

One more item to check is your thermostat.If its the wrong temp you won't get much heat.I ran a 170 in summer and 190 in winter.I soon found my car loves the 190 always.Also if your thermo is stuck open you won't over heat but,not much heat either.I have seen the blower "fan" break at the connection to the motor.It sounds like its running great,'cause it is! It's just not turning anything.Your answer is somewhere in the list from royce,tomanyz and myself.I cram a sock in the heater driver side duct and crack open the floor vent and my wife ,who loves heat,can toast peanuts on the passenger side.We always say we had the first dual climate car.Have fun! Daniel

[EScanlon]

All good fixes mentioned so far.

One more:

Check the cable that goes to the fresh air vent which is behind the blower motor housing. If your vent is stuck open and not being closed by the cable, then you will be trying to heat fresh COLD air all the time. Yes eventually the heater will warm the air, but not HEAT it.

Another quick way of telling if your heater core is plugged or restricted is to look inside the radiator cap. If the radiator shows a lot of buildup of calcium, minerals or other gunk, then it is a real good possibility that the core is plugged. To clean this it is much easier to find a replacement or take to a radiator shop if you can't get a replacement.

The Heater Water Control Valve can go bad over time. it is basically a plunger valve. When you actuate the lever it pulls a piston which in turn allows the water to flow. Usually the problem is that it won't shut off rather than it won't open though. DO check the cable on it. It is a good possibility that someone mis-adjusted it at some point and it is just barely coming open, however, that also indicates that it is being over tightened when you're shutting the water off.

By the way, as a check, you can ONLY get heat out of the defrost vents OR the floor, not both and definitely NONE out of the center or side vents. If you are getting ANY through the side / center vents then it definitely says you have internal flap problems.

If you have the time, and space you might consider removing the whole system and refurbishing the weatherstripping seals INSIDE the unit. Not too long ago someone posted that the flap seal which is on the flap to divert between defrost / room had fallen off and was actually blocking HALF of the heater core, resulting in heat out of the passenger side but NOT the driver side. Could this be your problem? Hard to say UNTIL you open the whole unit up.

Good Luck

[2ManyZs]

I got to thinking about something this morning sitting in another traffic jam on I-95. Doesn't the heater control valve cable connection have an adjustment on it where you set it and tighten a bolt down on the cable? It could be that the cable has just pulled through the clamp. If I'm right this could be a very simple fix, at least to get heat for the time being. But you should go through all the postings and do all of the things that are mentioned so that you won't have another problem crop up in the future, that is when you have the time to do them.

[EScanlon]

It is a very strong probability, and using Occam's Razor, it's probably the problem.

[2ManyZs]

OK, I must be a little dense, but what it Occam's Razor?

[EScanlon]

Occam's Razor is the maxim that assumptions introduced to explain a thing must not be multiplied beyond necessity.

(Named after William of Occam 14th Century English Philosopher)

Webster's Unabridged Encyclopedic Dictionary

Simply put: The simplest solution that encompasses all the facts.

OR

K.I.S.S.= Keep It Simple Stupid

Taught to engineers so that they don't get crazy coming up with possibilities with regards to a process or repair. Remember Rube Goldberg?

[thunderstreak]

Hello,

This is my first post. I am not trying to slam anyone just a little FYI. in response to this reply

"Check the cable that goes to the fresh air vent which is behind the blower motor housing. If your vent is stuck open and not being closed by the cable, then you will be trying to heat fresh COLD air all the time. Yes eventually the heater will warm the air, but not HEAT it. "

With the fresh air door in the closed position you will probably see condensation (fogging) begin to appearon your windows. I do not recommend driving in this mode. Recirculation mode is truely designed for 2 reasons 1)Max Air, is a recirculation mode, When the a/c is running. The evaporator acts as a dehumidifer, preventing fogging. 2) Air quality. When waiting at a light behind a desiel powerd vehicle, sorry they stink.

By the way in today's cars the a/c runs when you are in a Defrost mode and the fresh air door will open automatically.

Unfortunately I have yet to see a Z Car HVAC Unit yet as I am looking for a 240z myself.

Thanks for Forum,

Gene

[EScanlon]

Gene:

The 240 system has a pair of vents in the rear of the vehicle providing continuous air exhaust when the vehicle is moving.

The Heater select vent that differentiates between Vent and Heat only changes the position of the inside flap that determines whether you get air out of the center and side vents. In both positions the Fresh air is open and allowed to bring air in.

In this respect I was in error, but the check of the vent/heat flap rather than being behind the heater motor, is on the main housing, but connected on the left hand side of the box. If you have this flap open to get air out of the center or side vents then NO air is being forced through the heater core.

I am aware of 240's with Air Conditioning but only in the late 71 and up models. I may be wrong on this so someone please double check me.

To summarize the Heater Control Panel lever operations:

To Heat the car:

Air lever set to Heat.

Temp lever set between OFF and HEAT depending on temperature desired.

Def Lever set to Room (Floor).

To Defrost:

Air lever set to HEAT.

Temp lever set between OFF and HEAT depending on temperature desired.

Def Lever set to DEF (Inside Base of Windshield).

To Ventilate (Forced)

Air lever set to VENT.

Temp lever has no relation to the operation, BUT usually set to off.

Def Lever has no relation to the operation.

Closed:

Air lever set to OFF

Temp lever set to OFF.

Def Lever has no relation to the operation.

This is from the Owner's Manual for the 1971 240Z.