Recently I installed a electric fan on my L28 powered 240Z. Installation was pretty straightforward, so here goes; First, I went to Schucks Auto Supply, and found exactly what I was looking for. They have a fan relay/thermostat set up made by a company called Bueller. It cost me about $15, and was very simple for installation. Follow the directions carefully, and you can’t go wrong.
You will need to route power to the relay from two sources, one from an always “hot” source (battery positive, starter, or alt., your choice) This source will power your fan, and the lead provided is fused. The other source of power should only have power when the engine is on. Here is where a choice needs to be made. You can use an always “hot” lead here, but your fan can run any time the radiator is hot. This may be desired to people who’s cars tend to run hot, and are used on-and-off during hot weather. For most, I would think that a hot-with-ignition source would be sufficient, and desirable for safety. I used the ignition resistor feed wire for this purpose. You need to make sure that this lead is the one that provides a full 12 volts, and not lower. Less voltage may result in damage. Use a volt/ohmmeter to check the voltage source for 12 volts.
Remove the fan from the water pump. This was done on my 240Z without removing the radiator, but you may need to, depending on your model of Z- car. Reinstall the nuts to hold on the pulley. Make certain that they don’t “shank out” and appear to be tight before actually tightening against the pulley. Mine required the use of washers beneath the nuts to snug up the pulley. AGAIN, MAKE CERTAIN THE PULLEY IS TIGHT AGAINST THE WATER PUMP! If it is loose, it will spell disaster for your poor Z-car. Install your fan as per instructions provided with it. Mine I bought at Schucks also, and installed to the radiator through the fins with provided hardware. I bought a 12” fan, and now think that is a bit small for my car. Summer will tell. The relay/thermostat I have has a provision to run two fans, so I may add one in the future. Hook up the fan leads to the relay using the instructions provided with the relay. Once the wiring is hooked up, temporarily route it out of the way, and make sure your radiator is full, then start your car. Monitor the engine, checking for leaks, and any other problems. Touch the top radiator hose periodically, to feel for heat. When the thermostat opens, the top hose will get hot, and then you can see how well your fan works. (By the way, isn’t that engine quiet, now that the noisy fan isn’t there?)
There is a little adjustment screw on top of the thermostat control, and the instructions tell you how to set it. Be careful when turning this screw. It is sensitive, and can be damaged if it is cranked on with a lot of force. When the screw stops, don’t force it further, or you will break it. O.K. Watch the engine as it warms up… check your temp gauge. Is it where it normally resides when driving? If so, you can set your fan to come on now. Turn the screw on the thermostat until the fan just comes on. Now monitor the temp gauge, and the fan. The gauge should slowly go down, and then the fan should go off. Too hot for your taste? Turn the thermostat screw to turn on a bit sooner. Not hot enough? Turn it so the fan goes on later. This will require some trial and error on your part, but is simple stuff. Some people use a candy thermometer to judge how hot to set the thermostat, I used an infrared thermometer from my powdercoating set up. After you are satisfied with your settings, properly route the wiring to keep it protected from heat, chafing, and rotating objects. You could even hide it to retain a cleaner, more stock look, if desired. You may want to keep the thermostat accessible, however, to be able to adjust further should the need arise. Enjoy your quieter, slightly more powerful Z-car.
You will need to route power to the relay from two sources, one from an always “hot” source (battery positive, starter, or alt., your choice) This source will power your fan, and the lead provided is fused. The other source of power should only have power when the engine is on. Here is where a choice needs to be made. You can use an always “hot” lead here, but your fan can run any time the radiator is hot. This may be desired to people who’s cars tend to run hot, and are used on-and-off during hot weather. For most, I would think that a hot-with-ignition source would be sufficient, and desirable for safety. I used the ignition resistor feed wire for this purpose. You need to make sure that this lead is the one that provides a full 12 volts, and not lower. Less voltage may result in damage. Use a volt/ohmmeter to check the voltage source for 12 volts.
Remove the fan from the water pump. This was done on my 240Z without removing the radiator, but you may need to, depending on your model of Z- car. Reinstall the nuts to hold on the pulley. Make certain that they don’t “shank out” and appear to be tight before actually tightening against the pulley. Mine required the use of washers beneath the nuts to snug up the pulley. AGAIN, MAKE CERTAIN THE PULLEY IS TIGHT AGAINST THE WATER PUMP! If it is loose, it will spell disaster for your poor Z-car. Install your fan as per instructions provided with it. Mine I bought at Schucks also, and installed to the radiator through the fins with provided hardware. I bought a 12” fan, and now think that is a bit small for my car. Summer will tell. The relay/thermostat I have has a provision to run two fans, so I may add one in the future. Hook up the fan leads to the relay using the instructions provided with the relay. Once the wiring is hooked up, temporarily route it out of the way, and make sure your radiator is full, then start your car. Monitor the engine, checking for leaks, and any other problems. Touch the top radiator hose periodically, to feel for heat. When the thermostat opens, the top hose will get hot, and then you can see how well your fan works. (By the way, isn’t that engine quiet, now that the noisy fan isn’t there?)
There is a little adjustment screw on top of the thermostat control, and the instructions tell you how to set it. Be careful when turning this screw. It is sensitive, and can be damaged if it is cranked on with a lot of force. When the screw stops, don’t force it further, or you will break it. O.K. Watch the engine as it warms up… check your temp gauge. Is it where it normally resides when driving? If so, you can set your fan to come on now. Turn the screw on the thermostat until the fan just comes on. Now monitor the temp gauge, and the fan. The gauge should slowly go down, and then the fan should go off. Too hot for your taste? Turn the thermostat screw to turn on a bit sooner. Not hot enough? Turn it so the fan goes on later. This will require some trial and error on your part, but is simple stuff. Some people use a candy thermometer to judge how hot to set the thermostat, I used an infrared thermometer from my powdercoating set up. After you are satisfied with your settings, properly route the wiring to keep it protected from heat, chafing, and rotating objects. You could even hide it to retain a cleaner, more stock look, if desired. You may want to keep the thermostat accessible, however, to be able to adjust further should the need arise. Enjoy your quieter, slightly more powerful Z-car.