Rome Posted December 29, 2011 Share Posted December 29, 2011 Replacing gaskets on my car due to a blown head gasket, and noticed where the thermostat was is sopouse to be.. There was not a thermostat?? Now, i dont know what temperture theromstat to get? 180? 190? Ive heard 200??? Opinions? Facts? Anything is appreciated. Its just a fairly stock l28, header and dual 32/36 carbs. Quote Link to comment Share on other sites More sharing options...
josh817 Posted December 29, 2011 Share Posted December 29, 2011 190º for the winter, make sure it's facing the right way. Quote Link to comment Share on other sites More sharing options...
Rome Posted December 29, 2011 Author Share Posted December 29, 2011 Spring downward, Right? I live in Texas, its mostly 75+ degrees year round, still 190? Quote Link to comment Share on other sites More sharing options...
Rome Posted December 29, 2011 Author Share Posted December 29, 2011 Well you live in Texas too! Quote Link to comment Share on other sites More sharing options...
josh817 Posted December 29, 2011 Share Posted December 29, 2011 It's winter, we get some cold! Well maybe not you, further down south, so I guess 180º. I think it's spring down... I can't remember. Also make sure it has a little hole in it somewhere to get air out of the system and allow some bypass when it's closed. There is a separate hose that should run just before the thermostat to the water pump inlet which also serves as a bypass when the thermostat is closed. Quote Link to comment Share on other sites More sharing options...
MuhKaydenZ Posted December 29, 2011 Share Posted December 29, 2011 Spring downward, Right? I live in Texas, its mostly 75+ degrees year round, still 190? Is this right? I recently replaced mine cause it was overheating and didn't know which way to put it in I was thinking the previous one was bad and just replaced it the way the other one was. I seem to still have an issue though so if I have it backwards I would like to know thanks! Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 30, 2011 Share Posted December 30, 2011 (edited) Nissan offered three thermostats for the Z: Frigid, Temperate, and Tropical. The tropical was 76.5C (170F), Temperate 82C (180F), and Frigid 88C (190F) 1972 Nissan Part Numbers were: 21200-78502 Tropical 21200-A3001 Temperate 21200-A3005 Frigid I find that most places only stock FRIGID thermostats for a Nissan, therefore leading to cooling issues internally to the head. I use Chevrolet Thermostats as I can specify the temperature range above (160-195) and with the addition of a 1.5-2mm weep hole have exemplary performance. If it's cold, run a hot thermostat to get your oil up to operating temperature as quickly as possible to prevent sludge formation and condensate accumulation in the crankcase. <EDIT>Oh, to answer your question, in a 75F environment, the STANDARD thermostat was 180F (that is, for temperate climates meaning not extreme such as Siberia or Thailand.) Like I said, most places don't stock those so you're likely on your own unless you can cross the above numbers to a current issue Nissan Piece or go the Chevy route. The 'bypass when thermostat closed' function is provided by an internal drilling on the right side (oil filter) of the engine which shunts from the head to the inlet of the water pump. Additional bypass is provided by the external bypass line from the bottom of the thermostat, through any number of items or simply returning to the inlet of the water pump on the lower radiator hose casting. You can usually aid warmup by turning the heater to 'hot' but not turning on the fan--this allows quicker circulation inside the engine that can be provided by the smaller tandem bypass lines.<EDIT> Edited December 30, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
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