Genuine Nissan 21200-31U1B Thermostat Assembly

Product works as OEM should. Purchased this to replace a non-OEM brand that was about 1/3 the price. Application was a newly rebuilt 2005 Nissan 4.0L VQ40. Due to heat problems with the non-OEM installed on installation of the engine, I decided to test beforehand. Noted improvement over non-OEM in the pot as well at installed on the engine. Pan test included the original OEM, the non-OEM and the new OEM: OEM: 184*F - Began opening 190*F - Open to about 1/16" 198-200*F - over an 1/8" open 205*F - 3/16" or more open. Eg. fully open. OBDII connected to the ECM showed the engine never going over 210*F at 55/65MPH Compared to the non-OEM: 184*F - Closed 190*F - Closed 195*F - Began opening 200*F - just over 1/16" open 205*F - just over 1/8" open. Eg. not fully open. OBDII connected to the ECM showed the engine live temperature creeping to 220*F at 55/65MPH

I bought this to replace a brand new motorad thermostat that i installed on my xterra. The motorad was supposed to have the same specs as OEM but it didn't. Replaced it with this OEM thermostat and it fixed the problem. Engine fan hasn't ran since even on the highway, and the engine temp is maintained accurately. I live in Winnipeg MB. so in the winter my heater's blowing full-time, and even with the heater running as long as the truck is running the engine fan was working double time. Once it started warming up and the heater's turned off, especially on the highway, the engine temp would rise over the halfway mark which can't be healthy for your engine. I learned later that it's a "winter thermostat" supposedly intended to provide more heat for your cabin. I wouldn't sacrifice an engine to get warmer cabin heat.

No me gusto el producto no trabajo se atoraba y nunca abría con la temperatura del agua por ende calentaba

Perfect fit for my nissan frontier 2005

This arrived safe and sound. I installed it into my vehicle with no problems. All the holes lined up and the OEM gasket that I bought separately fit perfectly as well. Remember that you need a gasket, do not use your old one because you forgot to get one. To get the new thermostat to line up with the gasket while putting it on, put the gasket on it and then put 2 of the bolts/screws in the holes of it. I did the bottom 2 screws. I then placed it where it goes and screwed one in partially, not all the way. If you try to put it on one screw at a time, the gasket will keep slipping off and un aligning. After you partially screw in the first screw, do the same to the other one. Then you can install it with ease. While you’re in there, check your radiator hoses since you have the coolant and thermostat out.