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Installing an electric fan ?

974 views 14 replies 8 participants last post by  69612 
#1 ·
I'm installing an electric fan into my non AC 1973 Cadillac Hearse. Its going to be a supplement to the belt driven fan used as a pusher. The fan does not come with any relays, fuses, on/off switch or wiring. So what amp relay, switch and fuse should I use and what amp inline fuse ?
 
#7 ·
I'd reconsider your plans. The mechanical fan can pull 2 or 3 times the amount of air the pusher fan will and there would be a restriction. If your needing a supplement you might look in to repairing the problem and not patching it over.
 
#9 ·
There are many vehicles with an OEM aux pusher fan..... It'll do just fine with both. IMO I'd eliminate the mech fan and go with an dual electrical fan. I have adapted a mid 2000 Camaro dual fan with a Dakota Digital fan controller, works extremely well.
 
#10 ·
from the other side of the isle.

is the 73 caddy overheating when being driven..

install the OE TEMP 192F thermostat.

make sure that the radiator cap has a spring loaded dime sized disc in the middle of the sealing rubber.. what.. with the cap off.. shake it.. see the dime sized disc in the middle of the rubber seal. if it dangles loosely. change the cap to one that has the same 13 or 16 pound rating.. and has a spring loaded disc.

if your radiator is NOT CLOGGED either internally with corrosion or sludge.. and externally from road debris.. it should work with the stock fan and fan clutch. they are designed to run between 195 and 240F.. if the engine temp gets to 245 or 250.. there is a little hex device with either one or 2 push on terminals that grounds and turns on the STOP ENGINE METAL TEMP warning light on the dashboard.. the engine coolant temp light may or may not also go off.

the reason that caddy put the STOP ENGINE METAL TEMP light.. is when coolant was lost. the coolant temp sensor was not always close enough to the head to pickup heat without coolant flow.. so you could do significant damage.. before the coolant temp light came on. engine metal temp switches are still available in a few parts stores. they thread into a 3/8-16 hole.

i know you did not ask for this.. but i have worked on dozens of these caddies... from early 50s models thru the conversion to front wheel drive transverse engine models.
 
#13 ·
The engine does not overheat. Recently I've installed a new carb, timing chain and sent the cylinder heads out. Cleaned the combustion chambers as well. The fan does not have a clutch. This is Vegas and the other day it was 109 degrees here. The car pretty much ran fine but I could feel the heat blasting me in the face from the engine as I drove. This is a non AC car right from the factory. Once the heat gets up there out here, the car tend to have some pinging and also after run after I cut the ignition. I've tried 91 octane and it really didnt help. Once the ambient temp drops back down to the 95 and ubder range, those problems all vanish.
 
#15 · (Edited)
i had forgotten one thing..

one must verify that the smog pump belt it tight.. if you notice on your car. the fan and alternator belt only go around those pulleys.. not the crank..

the smog pump belt turns the fan and water pump pulley from the crank. those sometimes get loose and don't transfer enough torque to spin the fan and the alternator properly.

if its Pinging.. please verify the EGR system is working properly. EGR flow reduces the need for fuel. so the carbs are set lean.. if the EGR fails.. the engine will have more oxygen percentage than there is fuel and it will ping with a fast burning really hot lean mixture.. i use a vacuum gauge with a T connected to the vacuum hose to the EGR valve. take a ride with the gauge on the window to verify EGR operation.. these cars have an EGR backpressure transducer that can fail and you will never know it unless you perform this test..



please verify that the base timing is set properly.. but also remove the distributor cap.. grab the rotor and turn it against the advance springs. then release.. it should snap back freely.. if it binds and many do.. you may need to tear the distributor out and free up the mechanical advance on the shaft.. its probably full of hard grease and perhaps rust..
 
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