Thanks for sharing.  However, I was interested in learning about the OP's thought process with this issue as he seems to be very indecisive and often overwhelmed by ongoing maintenance issues experienced with his Z for the last three years.

FWIW, my experience with aftermarket thermostats is the opposite of what you've noted.  I've always had good service with aftermarket brands in the domestic and imported cars I've owned.  Go figure 

Dennis

Oh  I know what you mean about OP's ongoing pension for indecision. Which is one reason why I seldom respond to his threads any more. He is sloooowly getting there though.

I believe I recommended a Factory Nissan 160 thermostat over a year ago.... maybe two years. Maybe that is where he's coming from. If he can find a factory 160 stat, I still stand by that recommendation. All part of solving his fuel peculation problem, which he is finally, finally slowly solving

But yeah, it's really disappointing the state that the aftermarket is in these days. Global out sourcing has only helped the Bean counters. Quality control has gone for a huge nose dive.

So for some things I'll only buy genuine factory parts. GM,  Bosch and the Japanese groups seem to still have quality control over their OEM line ups. Everything else is suspect to me now.....

10 hours ago, Chickenman said:

Nissan part number for Tropical stat is 21200-78502. Supercedes to 21200-F3160. Nissan Parts Deals is showing limited availability. I'd call them and check stock and confirm temp stamping.

https://www.nissanpartsdeal.com/parts/nissan-thermostat~21200-78502.html

 

Available on E-bay as well: Confirm temp rating is approx 71.5 C= 160 F  by question to Seller. Don't worry about application

http://www.ebay.com/itm/1979-1986-Nissan-200SX-280ZX-Pulsar-NX-Sentra-Engine-Coolant-Thermostat-OEM-/191579574572?fits=Make%3ANissan&hash=item2c9b08512c:g:ueoAAOSwBahVaOEk&vxp=mtr

thanks Chickenman.

I opened the thermostat housing and discovered i had the 76.5° thermostat installed the gasket was worn and melted and had silicon rtv spreaded around the housing. Is this common?? Should i just remove the all melted gasket with a knife, sand it and place a new gasket as i did before installing the thermostat back in the housing or should i also add high temperature rtv silicone around? I guess i should purchase a 160°C instead of the one i have. At idle the temp gauge reaches until 3/4 when it should keep below 1/2.

My father used to have a Fiat 124 in the mids 70s and says i should remove the damn thermostat out of the system. Panama weather is hot (33°C) and this is not needed here!! I guess if Nissan design the system to be used with a thermostat it should be installed accordingly. Any thoughts on this??

have you ever tested the water temp to verify the actual temp (rather than trusting the gauge)?

1st thing is to determine if you have a problem. I presume that is 76.5c which is about 170f, should be fine.

Now check the actual water temp in the rad with a thermometer (like the kind used to check meat temps while cooking would be fine).

1) does the temp match what reads on the gauge? if not fix that part (sending unit, or gauge)

2) check the existing stat to see if it works (see video)

3) if it works and still running hot, maybe the rad is plugged.

the rad is plugged?????

Yes if the car is overheating and everything else is ok (stat opens, water pump working, correct amount of coolant, no head gasket leaks, fan working properly, hoses not collasping, then the only thing left is the heat exchange from the water in the radiator to the air flowing thru it. Radiator can become plugged up with rust and other debris ,esp if the coolant is not properly maintained. I suppose its possible the water pump could be so corroded that the impeller is not moving water, but I would guess the bearing would go bad before that.

dumb question: Do you guys replace the gasket that is sold together with the thermostat and seal the housing and cap with High Temperature RTV silicone or you just install the thermostat with the gasket and bolt it? If a permatex high temp silicone is recommended in addition to the OEM gasket, which one is recommended?

Use the gasket that came with it, no need for silicone on the gasket. Just make sure you have clean mating surfaces. I put a little anti seize compound on any nut that is screwed into aluminum. Don't overtighten.

Edited January 3, 20178 yr by Dave WM

The RTV may have been used if the metal surfaces of the thermostat housing were corroded and the paper gasket didn't make a good seal.  Check for smooth clean surfaces when you put it all back together.

Dennis

Removing the thermostat's restriction is like running the a/c with the windows down. The thermostat slows the coolant down and allows it to cool the motor. If it was to pass through too fast it won't cool. I made that mistake on my first Z in 1986. FYI

Nuh Uh.

Ya know...there is a theory out there about backpressure from a restricted exit raising the boiling point of the coolant on the engine (pressurized) side of the pump.  I think that's why the racers use about a 5/8" hole in a washer or metal plate when they run no thermostat.  Could be one of those "racer's edge" things, but still worth a consideration.  We should probably be measuring coolant pressure in the engine itself as a guide to most effective cooling.  More pressure reduces hot spots and "nucleative boiling" (I made that term up, but it might be real).