71' 521 overheateing. still... cfm?

1965-1971 Datsun 521 forums. All 520 and 521 topics and discussion can be found here.
tkellett
Posts: 5
Joined: Mon Jun 21, 2010 11:35 pm
Car: 1971 Datsun 1600 w/ 1975 L20B

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i have a 71' 521 with a slight overheating problem, in the summer it always overheats, i replaced the thermostat, water pump rad and now lastly im looking at the fan. when i got the truck the guy b4 me had cut th fan, i don't know how much but i suspect it ruined it's pulling power. so now im looking at putting in a e-fan, but im not sure on how much cfm i need, can anyone point me in a direction? thanks!


Jefe De Jefes
Posts: 31
Joined: Wed Dec 31, 1969 5:00 pm
Location: Fresno County, California

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Remove your thermostat in the summer?
Replace your fan?
Do you have a fan shroud?
Check your timing?

rocky1234
Posts: 17
Joined: Sun Oct 16, 2011 7:22 am

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run engine at operating temp..........turn off engine....pull off neg cable............check with palm the rad. core all over if cold spot replace rad

picturearts
Posts: 9
Joined: Sun Feb 12, 2012 5:24 pm
Car: 1972 Datsun Pickup 521

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Have shop check for exhaust gases in the coolant, (bad gasket, crack in head or block) leaks gasses into water and heats it up, if okay, have shop check temp of the radiator (digi thermo) top of radiator and bottom, should be much cooler at bottom (like 15 degrees, if not, radiator bad. (Iagree with Rocky 1234)
Chances are its the RAD, they do go bad, fins just don't distro the heat, most overlooked problem, and a relatively cheap fix. Hope this helps.
(pesumed you have checked, timing, plug heat range, thermostat, bad hoses collapse when hot, radiator cap, flow of coolant when up to temp, water pump)


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