Postby smj999smj » Fri Jan 22, 2016 2:10 pm
Well, it "could" be a bad solenoid. You'd have to test the circuit, resistance test the solenoid and possibly some other checks. If it is an intermittent failure, it makes it much more difficult to determine. The problem with it being a solenoid is that they are very hard to find individually and Nissan sells them as part of an expensive, valve body/TCM assembly. If it only happened once, I would wait and see if it happens again before doing anything.
As far as the radiator, look for a Calsonic sticker on the top of the tank. There will be a part number of 21400-EA215, -EA265 or possibly even -EA200 if it has the original radiator. If it has 21400-9CA2E, you have a Nissan replacement radiator, which, depending on how early of a unit it is, may or may need be the "updated" unit. Apparently, the correction was made under this part number, but a few with the -9CA2E part number have had the cooler fail, as well. The current radiators from Nissan are updated, but are expensive at $550 MSRP. They also have a discounted radiator for $350.
Aftermarket radiators will not have the Calsonic sticker on the top tank. They also will not have "NISSAN" molded into the top of the tank. They may or may not have the same petcock as the OEM radiator (different thread pitch and/or a tab you can turn with your hand, rather than a Phillips cross-four provision). The aftermarket radiators have been reliable, so far, as we can tell. I haven't heard of any cooler failures, although my friend installed a Denso unit and the tank developed a small crack in the tank less than a month later. Most aftermarkets are made in China, but they seem to be of good quality. I purchased an Ebay radiator for $92 four years ago and it's been fine. Spectra-Premium is a popular option and Stillen has an all aluminum radiator for $350, although I have heard of one member having a problem with it; I'm not sure if it was just a one-time thing or a design issue or if it's been correctly.