1977 280z Radiator clutch fan engaged too frequent

[siteunseen]

I've always read that if you can spin the fan blades around more than one or 1.5 complete rotations while the car is off and "cold" the clutch could be bad. Another way that's a little trickier is if you can stop the running fan with a piece of cardboard it's most likely bad.  They're oil filled so it should be harder to spin freely by hand before cranking while the oil is cool. 

They are cheap, or used to be , available and not too hard to replace.

I'm more concerned about the oil pressure gauge. 

[SteveJ]

Here are links for parts/pieces/tools that may be useful for addressing issues brought up in this thread.

Verifying the voltmeter: https://www.amazon.com/dp/B01M9IKYVH Plug it into the cigarette lighter (provided it works). These things are handy to have.

Verifying the oil pressure:

Adapter that allows a mechanical gauge to be added: https://www.glowshiftdirect.com/1-8-bspt-male-to-1-8-27-npt-female-hex-thread-adapter/

Mechanical oil pressure gauge: https://www.amazon.com/Equus-5244-Mechanical-Pressure-Gauge/dp/B0747VR5WX

Verifying the temperature: https://www.harborfreight.com/121-infrared-laser-thermometer-63985.html

I haven't seen anything wrong with water temp. I'm not sure the fan clutch kicking in is a problem unless it keeps the engine too cool.

[240zadmire]

Those are really nice goodies!  Thank you!  Got some of them.  Will get the rest to pimp up my ride 🙂 

The clutch fan brand is Aisin.  Not sure where it made.  At cold or warm up, spin by hand moves couple of inches.  Don’t mind replacing it.

the volt gauge might not display correct?!. I measured at idle and rev up at the battery terminal and the voltage is less than 13v.  This is when all lights were on.

Edited August 18, 2022 by 240zadmire

[Zed Head]

Just realized it's a 280Z.  You'll get much better responses if you put your car details in your sig.  My earlier reply was for a 73 240Z.  Your screen name has 240Z in it.

Looks like it's the same system though.

p.s. I don't pay attention to the titles after I open a thread.  

Edited August 18, 2022 by Zed Head

[Yarb]

Amazon has the adapter as well from Glow shift

[240zadmire]

hahaha, I just learned how to update the signature.  Your comment still relevant and helpful, nevertheless.

 

[SteveJ]

3 hours ago, 240zadmire said:

Those are really nice goodies!  Thank you!  Got some of them.  Will get the rest to pimp up my ride 🙂 

The clutch fan brand is Aisin.  Not sure where it made.  At cold or warm up, spin by hand moves couple of inches.  Don’t mind replacing it.

the volt gauge might not display correct?!. I measured at idle and rev up at the battery terminal and the voltage is less than 13v.  This is when all lights were on.

That voltage is on the low side. It should really be reading around 14 above 2000 RPM.

I suggested the cigarette lighter voltmeter because it's easy to compare it to the voltmeter in a 280Z and know what the voltage is while you're driving around.

[Racer X]

14 hours ago, 240zadmire said:

Those are really nice goodies!  Thank you!  Got some of them.  Will get the rest to pimp up my ride 🙂 

The clutch fan brand is Aisin.  Not sure where it made.  At cold or warm up, spin by hand moves couple of inches.  Don’t mind replacing it.

the volt gauge might not display correct?!. I measured at idle and rev up at the battery terminal and the voltage is less than 13v.  This is when all lights were on.

If you are measuring the voltage at the battery, you are only seeing the battery state of charge. Around 13 volts is OK.

Measuring the output of the alternator you should see closer to 14 volts as the alternator is operating.

 

[Racer X]

17 hours ago, 240zadmire said:

I took the radiator to the shop and put back afterward.  It was relatively easy by removed the radiator shroud and able to pull the radiator off.  The fan was intact during the whole operation. 

 

the fan clutch, thermostat, coolant temperature sensor are couple of thousands miles old.  The clutch has resistant both at cold as well as when the engine was off from a long drive.

My logic behind the coolant brand is that as the radiator fan draws the heat from the radiator, it heats up the clutch fan that allows the clutch fan to engage.   If the coolant boiling point is too low/high, it might indirectly affect the clutch fan engage prematurely.

 

when the clutch engaged, I’d say about less than 30 seconds then the clutch disengage.  I don’t think the car is any hotter than before.  In term of where the temperature needle was… when the clutch engaged, needle gradually went down to middle and the clutch disengaged.  The needle never completely pass the letter F.  It just one of those things I noticed that behave differently than it used to be. 
 

take a look at the photos below.  This is at idle at red light after 15 minutes of driving in the morning.  Around 8:10am.  The outside temperature was in the low 70F.

as I stepped on the gas pedal from the red light, the clutch fan engaged, around 3rd gear, then disengaged after couple of seconds.

 

I'd be most concerned about the oil pressure reading. Confirm the pressure by using a mechanical gauge.

[SteveJ]

19 minutes ago, Racer X said:

If you are measuring the voltage at the battery, you are only seeing the battery state of charge. Around 13 volts is OK.

Measuring the output of the alternator you should see closer to 14 volts as the alternator is operating.

 

In the first photo, you can see the fan is blurred, so the car is running. Unless @240zadmirehad not tried to rev the engine to excite the alternator before that photo, the voltage is low. Since the alternator and battery are connected, you should see the same voltage at both. The only thing that would drop the voltage at the battery is corrosion.

[240zadmire]

The car was running.  The second photo I rev up the engine while trying to take a photo.  As you can see I had to put the voltmeter on the fuel rail and my right thumb on the throttle linkage on the second photo, on the right. 
 

while waiting for the goodies to arrive….

I need a little bit help locate the condenser as highlighted in the photo below.  Look like the temp, oil pressure… all connected to this condenser.  It also connected to cooling fan motor sub-harness.  What and where is that?  There’s only 2 fans I know off, radiator fan and the heater/ac motor fan. 

[240zadmire]

Found the condenser.  How to check if it’s working?