ZCar Forum banner

Status
Not open for further replies.
1 - 9 of 9 Posts

·
Registered
Joined
·
168 Posts
Discussion Starter #1
Just installed an 16" electric puller fan with a temp controller and an override switch and the car still heats up at idle/low speeds! I have been through every part of the cooling system on this car and the motor has been rebuilt. It is a 77 with air. It does not matter how cool it is outside, it still gets hot at low speeds. I'm lost.
 

·
Registered
Joined
·
205 Posts
on some vehicles there is a piece of sheetmetal or such that extends from the bottom edge of the radiator going fwd to the grill opening. I pulled the fiberboard piece off of my 924 due to it falling apart and at low speed or behind traffic aka tailgating it would try to overheat. As soon as I got it into clean air it would be fine.
drove me crazy for 3 years till I figured it out
Don't know about z specifics but my zx has such a part.
you can also try putting the fan shroud back on over the top of the electric fan.


ps both ways help to keep the fan from pulling engine compartment hot air back through the radiator
 

·
Registered
Joined
·
79 Posts
We need details...

Get more specific for us...
You say you have been through the cooling system but define that a little better for us.
Is the radiator brand new, recored or just as it came on the car?
What is the thermostat opening temperature?
What mix of water/anti-freeze are you running?
What is the engine timing set at?
What condition are the radiator hoses?
Details will help.

Speaking personally; I have a 77 280Z stock with the stock radiator and a 16" Perma-cool fan. 180 degree thermostat and a 50/50 mix of water/anti-freeze. My car has factory AC and the electric fan NEVER runs (I live in Alabama so it is hot and humid) unless I am sitting still in summer weather. If the car is moving it just doesn't get hot at all. Some cars do have a hot nature, though.
Good luck.

Craig
 

·
Registered
Joined
·
263 Posts
Re: We need details...

If everthing is in good shape and working right this may help: 1. you need 2 electric fans on alot of Z's. 2. 80% water 20% antifreeze. 3. 160 degree thermostat. 4. a bottle of red line wetter water in the radiator. Good luck!
 

·
Registered
Joined
·
2,156 Posts
move to alaska?

sounds like a blocked thermostat
or bad water pump or radiator cap. when u open the top of the radiator after its
warm do u see water flowing ?
 

·
Registered
Joined
·
168 Posts
Discussion Starter #8
Details

Details
1) The radiator was re-cored last summer to try to cure the problem. New stant rad. cap.
2) Thermostat is 180 and is working. I can tell by letting the car warm up and when temp gauge reaches 1/2, the upper hose gets warm and water circulates.
3) I run a 50/50 mix
4) Timing is 10 but I've gone advance and retard by 5 degrees with no difference.
5) Hoses are all new.

Additional. Car has had 3 different water pumps. There is no blockage in water jackets as the motor was rebuilt which included full machining on the block and head. The car had this problem with the original motor which I attributed to age.

If it is one thing it is consistent. It can be 45 outside or 103 and there is little difference. HOT HOT HOT while idling but cools right back down. As long as I am moving along I can drive it without the fan. The instructions on the fan may be incorrect which is why it is not cooling it down. I screwed if the blades are backwards as it will never come off.

Thanks for the advice.
 

·
Registered
Joined
·
4,289 Posts
Re: Details

How hot is hot. Remove the rad cap and put a thermometer in the rad or install a real temperature gauge.

Your gauge sending unit may be defective.

The "Thermal Transmitter" is connected to the Temperature Gauge in the Dash. It has a single "male" bullet connector built into the end of the sensor.

To test the circuit in the car wiring, disconnect the wire at the sending unit (it is at the 10:00 position looking at the front of the motor in a 79 280 n/a) and ground it. The dash meter should go all the way to "Hot".

With the bullet connector completely disconnected the gauge should read "Cold".

To test the "Thermal Transmitter" hook an ohm meter between the terminal on the transmitter and battery ground and start the engine.

You should see the following:

23 C = 400 ohms
25 C = 386 - 365 ohms
30 C = 302 - 290
35 C = 238 - 228
40 C = 190 - 183
45 C = 153 - 149
50 C = 123 - 118
55 C = 98 - 95
60 C = 84.1 - 80.3
65 C = 69.0 - 67.2
70 C = 56.5 - 56.0

So as the temperature increases the resistance decreases and you can use the above to test the functionality of your sending unit.

Wayne Monteath
Masham, Quebec.
 
1 - 9 of 9 Posts
Status
Not open for further replies.
Top