Originally i bought a new T-stat because i wasnt seeing a new seal for sale.

i put in a Gates brand back in 2016 and im seeing antifreeze comin outta the housing now. Could i just clean up the housing and put water pump RTV?

im seeing the TAMA t-stat for sale on Parts Geek. It says its the original manufacturer.
I would assume its exact as was in it before?

I don't know how a specific brand of thermostat could be causing coolant to leak out of the housing. It is probably more likely that the gasket that was used was not as good as it should have been. Fixing the leak, changing the gasket, does not mean the thermostat has to be replaced. The thermostat would not be damaged by the leak.

If you want to use RTV instead of a gasket, go ahead. Just be sure to give it enough drying time before filling the cooling system.

I don't know what brand thermostat Nissan used when they built the car. But it is a Japanese company. https://www.tama-e.co.jp/en

Yeah thats the brand they're selling on Parts Geek.
the gates gasket is a more square type rubber seal.
the t-stat that was in had a seal that was more rounded out.
this i wish i woulda used RTV with cause now i gotta take it back out and re-seal.

Tstat should be 180 and you have to use RTV on both sides of gasket if it's a pos paper one. 203 will absolutely cause overheating (IMO as temp shouldn't go over 210) as that temp shouldn't be hit except in summer heat with A/C on. It's stupid enough that the fans don't kick on till 195.

yeah thats the way the 3.5 is. They took the upper stat from the design.
the 3.0 unfortunately had two stats. The 203º stat was on the left side. Fans on the 3.0 come on in traffic at 204º.
this stat has a rubber seal around it.
its like this in a lot of makes where its a rubber seal around the edge. Theres no way to buy just the rubber seal.

Ive read not to RTV intake parts & exhaust manifolds
the silicone can lodge into the catalytic converter and can cause clogging

Misinformation IMHO

wat? i use high heat silicone on exhaust parts/manifolds all the time and use it on intake gaskets. i worked as a tech for nearly a decade and all the other guys slathered the stuff on exhausts, ive never heard of it clogging cat converters

i usually use silicone and gaskets combined for thermostats, unless its just me that has ***** luck the style of thermostat like 5th gens have that just has the thin rubber "outline" gasket always end up sweating coolant and theres crust around the housing within weeks or it slowly drips. my Toyotas do it too, doesnt matter what brand the thermostat or anything